Earth science (also known as geoscience, the geosciences or the Earth Sciences), is an all-embracing term for the sciences related to the planet Earth. It is arguably a special case in planetary science, the Earth being the only known life-bearing planet. There are both reductionist and holistic approaches to Earth science. There are four major disciplines in earth sciences, namely geography, geology, geophysics and geodesy. These major disciplines use physics, chemistry, biology, chronology and mathematics to build a quantitative understanding of the principal areas or spheres of the Earth system.
Earth's spheres
Earth science generally recognizes 4 spheres, the lithosphere, the hydrosphere, the atmosphere, and the biosphere; these correspond to rocks, water, air, and life. Some practitioners include, as part of the spheres of the Earth, the cryosphere (corresponding to ice) as a distinct portion of the hydrosphere, as well as the pedosphere (corresponding to soil) as an active and intermixed sphere.
The following fields of science are generally categorized within the geosciences:
* Geology describes the rocky parts of the Earth's crust (or lithosphere) and its historic development. Major subdisciplines are mineralogy and petrology, geochemistry, geomorphology, paleontology, stratigraphy, structural geology, engineering geology and sedimentology.
* Geophysics and Geodesy investigate the figure of the Earth, its reaction to forces and its magnetic and gravity fields.
Geophysicists explore the Earth's core and mantle as well as the tectonic and seismic activity of the lithosphere.
* Soil science covers the outermost layer of the Earth's crust that is subject to soil formation processes (or pedosphere). Major subdisciplines include edaphology and pedology.
* Oceanography and hydrology (includes limnology) describe the marine and freshwater domains of the watery parts of the Earth (or hydrosphere). Major subdisciplines include hydrogeology and physical, chemical, and biological oceanography.
* Glaciology covers the icy parts of the Earth (or cryosphere).
* Atmospheric sciences cover the gaseous parts of the Earth (or atmosphere) between the surface and the exosphere (about 1000 km). Major subdisciplines are meteorology, climatology, atmospheric chemistry and atmospheric physics.
* A very important linking sphere is the biosphere, the study of which is biology. The biosphere consists of all forms of life, from single-celled organisms to pine trees to people. The interactions of Earth's other spheres - lithosphere/geosphere, hydrosphere, atmosphere and/or cryosphere and pedosphere - create the conditions that can support life.
Earth's interior
Plate tectonics, mountain ranges, volcanoes, and earthquakes are geological phenomena that can be explained in terms of energy transformations in the Earth's crust.
Beneath the earth's crust lies the mantle which is heated by the radioactive decay of heavy elements. The mantle is not quite solid and consists of magma which is in a state of semi-perpetual convection. This convection process causes the lithospheric plates to move, albeit slowly. The resulting process is known as plate tectonics.
Plate tectonics might be thought of as the process by which the earth resurfaces itself. Through a process called spreading ridges (or seafloor spreading), the earth creates new crust by allowing magma underneath the lithosphere to come to the surface where it cools and solidifies--becoming new crust, and through a process called subduction, excess crust is pushed underground--beneath the rest of the lithosphere--where it comes into contact with magma and melts--rejoining the mantle from which it originally came.
Areas of the crust where new crust is created are called divergent boundaries, and areas of the crust where it is brought back into the earth are called convergent boundaries. Earthquakes result from the movement of the lithospheric plates, and they often occur near covergent boundaries where parts of the crust are forced into the earth as part of subduction.
Volcanoes result primarily from the melting of subducted crust material. Crust material that is forced into the Asthenosphere melts, and some portion of the melted material becomes light enough to rise to the surface--giving birth to volcanoes.
Earth's electromagnetic field
An electromagnet is a magnet that is created by a current that flows around a soft-iron core. Earth has a soft iron core surrounded by semi-liquid materials from the mantle that move in continuous currents around the core; therefore, the earth is an electromagnet. This is referred to as the dynamo theory of Earth's magnetism. The fact that Earth is an electromagnet helps it maintain an atmosphere suitable for life.
Atmosphere
The magnetosphere shields the surface of Earth from the charged particles of the solar wind. It is compressed on the day (Sun) side due to the force of the arriving particles, and extended on the night side. (Image not to scale.)
Earth is blanketed by an atmosphere consisting of 78.0% nitrogen, 20.9% oxygen, and 1% Argon. The atmosphere has five layers: troposphere, stratosphere, mesosphere, thermosphere, and exosphere; and 75% of the atmosphere's gases are in the bottom-most layer, the troposphere.
The magnetic field created by mantle's internal motions produces the magnetosphere which protects the earth's atmosphere from the solar wind. It is theorized that the solar wind would strip away earth's atmosphere in a few million years were it not for the earth's electromagnet. And since earth is 4.5 billion years old, earth would not have an atmosphere by now if there were no magnetosphere.
The atmosphere is composed of 78% nitrogen and 21% oxygen. The remaining one percent contains small amounts of other gases including CO2 and water vapors. Water vapors and CO2 allow the earth's atmosphere to catch and hold the sun's energy through a phenomenon called the greenhouse effect. This allows earth's surface to be warm enough to have liquid water and support life.
In addition to storing heat, the atmosphere also protects living organisms by shielding the earth's surface from cosmic rays. Note that the level of protection is high enough to prevent cosmic rays from destroying all life on Earth, yet low enough to aid the mutations that have an important role in pushing forward diversity in the biosphere.
Methodology
Like all other scientists, Earth scientists apply the scientific method. They formulate hypotheses after observing events and gathering data about natural phenomena, and then they test hypotheses from such data.
A contemporary idea within earth science is uniformitarianism. Uniformitarianism says that "ancient geologic features are interpreted by understanding active processes that are readily observed". Simply stated, this means that features of the Earth can be explained by the actions of gradual processes operating over long periods of time; for example, a mountain need not be thought of as having been created in a moment, but instead it may be seen as the result of continuous subduction, causing magma to rise and form continental volcanic arcs.
Partial list of the major Earth Science topics
Atmosphere
* Atmospheric chemistry
* Climatology
* Meteorology
o Hydrometeorology
* Paleoclimatology
Biosphere
* Biogeography
* Paleontology
o Palynology
o Micropaleontology
* Geomicrobiology
Hydrosphere
* Hydrology
o Limnology
* Hydrogeology
* Oceanography
o Chemical oceanography
o Marine biology
o Marine geology
o Paleoceanography
o Physical oceanography
Lithosphere or geosphere
* Geology
o Economic geology
o Engineering geology
o Environmental geology
o Historical geology
+ Quaternary geology
o Planetary geology
o Sedimentology
o Stratigraphy
o Structural geology
* Geography
o Physical geography
* Geochemistry
* Geomorphology
* Geophysics
o Geochronology
o Geodynamics (see also Tectonics)
o Geomagnetics
o Gravimetry (also part of Geodesy)
o Seismology
* Glaciology
* Hydrogeology
* Mineralogy
o Crystallography
o Gemology
* Petrology
* Speleology
* Volcanology
Pedosphere
* Soil science
o Edaphology
o Pedology
Systems
* Environmental science
* Geography
o Human geography
o Physical geography
* Gaia hypothesis
Others
* Cartography
* Geoinformatics (GIS)
* Geostatistics
* Geodesy and Surveying
* NASA Earth Science Enterprise
Friday, November 21, 2008
Ecophagy
Ecophagy is a term coined by Robert Freitas that means, literally, the consuming of an ecosystem.
Freitas used the term to describe a scenario involving molecular nanotechnology gone awry. In this situation (called the grey goo scenario) out-of-control self-replicating nanorobots consume entire ecosystems, resulting in global ecophagy. However, the word "ecophagy" is now applied more generally in reference to any event--nuclear war, the spread of monoculture, massive species extinctions--that might fundamentally alter the planet. Scholars suggest that these events might result in ecocide in that they would undermine the capacity of the earth to repair itself. Others suggest that more mundane and less spectacular events--the unrelenting growth of the human population, the steady transformation of the natural world by human beings--will eventually result in a planet that is considerably less vibrant, and one that is, apart from humans, essentially lifeless. These people believe that the current human trajectory puts us on a path that will eventually lead to ecophagy. In the paper in which Freitas coined the term he wrote:
Perhaps the earliest-recognized and best-known danger of molecular nanotechnology is the risk that self-replicating nanorobots capable of functioning autonomously in the natural environment could quickly convert that natural environment (e.g., "biomass") into replicas of themselves (e.g., "nanomass") on a global basis, a scenario usually referred to as the "grey goo problem" but perhaps more properly termed "global ecophagy".
Freitas used the term to describe a scenario involving molecular nanotechnology gone awry. In this situation (called the grey goo scenario) out-of-control self-replicating nanorobots consume entire ecosystems, resulting in global ecophagy. However, the word "ecophagy" is now applied more generally in reference to any event--nuclear war, the spread of monoculture, massive species extinctions--that might fundamentally alter the planet. Scholars suggest that these events might result in ecocide in that they would undermine the capacity of the earth to repair itself. Others suggest that more mundane and less spectacular events--the unrelenting growth of the human population, the steady transformation of the natural world by human beings--will eventually result in a planet that is considerably less vibrant, and one that is, apart from humans, essentially lifeless. These people believe that the current human trajectory puts us on a path that will eventually lead to ecophagy. In the paper in which Freitas coined the term he wrote:
Perhaps the earliest-recognized and best-known danger of molecular nanotechnology is the risk that self-replicating nanorobots capable of functioning autonomously in the natural environment could quickly convert that natural environment (e.g., "biomass") into replicas of themselves (e.g., "nanomass") on a global basis, a scenario usually referred to as the "grey goo problem" but perhaps more properly termed "global ecophagy".
Eco-marathon
The Eco-Marathon is an annual competition sponsored by Shell, in which participants build special vehicles to achieve the highest possible fuel efficiency. The Eco-Marathon is held around the world with events in the UK, Finland, France, Holland, Japan, and the USA.
The events are entered by a range participants from enthusiastic amateurs to university teams and major motor manufacturers with a variety of designs. The only two motor manufacturers to have any success in the event have been Ford and Honda.
A world record was set by a French team in 2003 called Microjoule with a performance of 10705 mpg-imp (3,790 km/l/8,914 mpg-US). The current record is 12665 mpg-US (5,384 km/l/15,210 mpg-imp), set in 2005 by the PAC-Car II. In contrast, the most efficient diesel passenger cars achieve 60 mpg-US (26 km/l/72 mpg-imp), and some high-powered sportscars achieve as little as 6 mpg-US (3 km/l/7 mpg-imp).
History
The event's history stretches back nearly seventy years. In 1939, a group of Shell scientists based in a research laboratory in Wood River, Illinois, USA, had a friendly bet to see who could drive their own car furthest on one gallon of fuel. At the time, 17.7 km/L (50 mpg-imp/42 mpg-US) was the best that could be achieved. That idea was the foundation for this international event, and the first competition was held in Mallory Park in the UK in 1977, (1976 international competition "Pisaralla Pisimmälle" was held in Finland (Keimola)).
Over the past 30 years, fuel economy has improved dramatically. Shell points out that "it would be possible for the winning Shell Eco-Marathon UK car to travel three times around the equator on the same amount of fuel that Concorde needed to reach the end of the runway."
The competition
The Eco-Marathon has different classes of competition: Fuel cell-powered, solar cell-powered, gasoline-fueled, diesel-fueled, and LPG-fueled. During the competition, cars must attain an average speed of at least 15 mph (23 km/h) over a distance of 10 miles (16 km). The course is typically a motor racing track—for the pan-European meet, the Circuit Paul Armagnac in Nogaro, France, for the English meet, the infield automobile competition course at Rockingham Motor Speedway in Corby, and the Americas, the automobile competition course at the California Speedway in Fontana. The fuel is strictly measured out for each entrant. At the end of the course, the amount of fuel used is measured; from that figure, fuel economy is calculated.
The marathon includes a set of rules to create a set of safe conditions for the event. Some of the rules for the event may encourage participants to enter vehicles that use hydrocarbon-based fuel sources. For instance, the Eco-marathon places solar-powered vehicles in their own class and are excluded from winning the $10,000 grand prize.
Another rule eliminates the use of an EGR valve, which reduces greenhouse gases in internal combustion engines. The marathon requires entrants to use Shell oil products exclusively when gasoline or diesel fuel are the sources of energy.
Entrants
The top performing vehicles are specially designed for high efficiency. Some vehicles use a coast/burn technique whereby they briefly accelerate from 10 to 20mph (from 16 to 32km/h) and then switch the engine off and coast for approximately 2 minutes until the speed drops back down to 10mph (16 km/h). This process is repeated resulting in average speed of 15mph for the course. Typically the vehicles have:
* Automobile drag coefficients (Cd) <>
* Rolling resistance coefficients <>
* Weight without driver of <>
* Engine efficiency of <>
The vehicles are highly specialized and optimized for the event and are not intended for every day use. The designs represent what can be achieved with current technology and offer a glimpse into the future of car design based on minimal environmental impact in a world with reduced oil reserves. The work of the participants can be used to show ways manufacturers could redesign their products.
Teams who have participated in the competition include
* Team Green
* Microjoule
* Eco-Runner Team Delft
* Trinity School Racing
* Aemval
* Pac-car
* Sandbach School
* Team Schluckspecht
* Team TIM
* Fortis Saxonia
* Eco Motion Team by ESSTIN
* Remmi-Team
Criticism
The cars in this competition are highly impractical for consumer use. They carry no passengers, and the driver is often forced into an uncomfortable position in order to reduce aerodynamic drag. The cars are designed to achieve maximum efficiency at 15 miles per hour (mph) (23 km/h), and some are incapable of exceeding 30 mph (48 km/h). They have few safety or comfort features, and most are not street legal.
The events are entered by a range participants from enthusiastic amateurs to university teams and major motor manufacturers with a variety of designs. The only two motor manufacturers to have any success in the event have been Ford and Honda.
A world record was set by a French team in 2003 called Microjoule with a performance of 10705 mpg-imp (3,790 km/l/8,914 mpg-US). The current record is 12665 mpg-US (5,384 km/l/15,210 mpg-imp), set in 2005 by the PAC-Car II. In contrast, the most efficient diesel passenger cars achieve 60 mpg-US (26 km/l/72 mpg-imp), and some high-powered sportscars achieve as little as 6 mpg-US (3 km/l/7 mpg-imp).
History
The event's history stretches back nearly seventy years. In 1939, a group of Shell scientists based in a research laboratory in Wood River, Illinois, USA, had a friendly bet to see who could drive their own car furthest on one gallon of fuel. At the time, 17.7 km/L (50 mpg-imp/42 mpg-US) was the best that could be achieved. That idea was the foundation for this international event, and the first competition was held in Mallory Park in the UK in 1977, (1976 international competition "Pisaralla Pisimmälle" was held in Finland (Keimola)).
Over the past 30 years, fuel economy has improved dramatically. Shell points out that "it would be possible for the winning Shell Eco-Marathon UK car to travel three times around the equator on the same amount of fuel that Concorde needed to reach the end of the runway."
The competition
The Eco-Marathon has different classes of competition: Fuel cell-powered, solar cell-powered, gasoline-fueled, diesel-fueled, and LPG-fueled. During the competition, cars must attain an average speed of at least 15 mph (23 km/h) over a distance of 10 miles (16 km). The course is typically a motor racing track—for the pan-European meet, the Circuit Paul Armagnac in Nogaro, France, for the English meet, the infield automobile competition course at Rockingham Motor Speedway in Corby, and the Americas, the automobile competition course at the California Speedway in Fontana. The fuel is strictly measured out for each entrant. At the end of the course, the amount of fuel used is measured; from that figure, fuel economy is calculated.
The marathon includes a set of rules to create a set of safe conditions for the event. Some of the rules for the event may encourage participants to enter vehicles that use hydrocarbon-based fuel sources. For instance, the Eco-marathon places solar-powered vehicles in their own class and are excluded from winning the $10,000 grand prize.
Another rule eliminates the use of an EGR valve, which reduces greenhouse gases in internal combustion engines. The marathon requires entrants to use Shell oil products exclusively when gasoline or diesel fuel are the sources of energy.
Entrants
The top performing vehicles are specially designed for high efficiency. Some vehicles use a coast/burn technique whereby they briefly accelerate from 10 to 20mph (from 16 to 32km/h) and then switch the engine off and coast for approximately 2 minutes until the speed drops back down to 10mph (16 km/h). This process is repeated resulting in average speed of 15mph for the course. Typically the vehicles have:
* Automobile drag coefficients (Cd) <>
* Rolling resistance coefficients <>
* Weight without driver of <>
* Engine efficiency of <>
The vehicles are highly specialized and optimized for the event and are not intended for every day use. The designs represent what can be achieved with current technology and offer a glimpse into the future of car design based on minimal environmental impact in a world with reduced oil reserves. The work of the participants can be used to show ways manufacturers could redesign their products.
Teams who have participated in the competition include
* Team Green
* Microjoule
* Eco-Runner Team Delft
* Trinity School Racing
* Aemval
* Pac-car
* Sandbach School
* Team Schluckspecht
* Team TIM
* Fortis Saxonia
* Eco Motion Team by ESSTIN
* Remmi-Team
Criticism
The cars in this competition are highly impractical for consumer use. They carry no passengers, and the driver is often forced into an uncomfortable position in order to reduce aerodynamic drag. The cars are designed to achieve maximum efficiency at 15 miles per hour (mph) (23 km/h), and some are incapable of exceeding 30 mph (48 km/h). They have few safety or comfort features, and most are not street legal.
Denudation
Denudation is the process by which the removal of material, through means of erosion and weathering, leads to a reduction of elevation and relief in landforms and landscapes. Exogenic processes, including the action of water, ice, and wind, predominantly involve denudation. Denudation can involve the removal of both solid particles and dissolved material. Both mechanical and chemical weathering occurs in relation to geomorphological landforms. At present the most significant processes leading to denudation include deforestation (including slash-and-burn practises of local peoples), overgrazing and certain forms of intensive farming which lead to large scale erosion.
Factors affecting Denudation include:
1. Surface geography
2. Properties of Earth material
3. Climate
4. Tectonic setting
5. Activities of man, animals and vegetation
Factors affecting Denudation include:
1. Surface geography
2. Properties of Earth material
3. Climate
4. Tectonic setting
5. Activities of man, animals and vegetation
Developed country
The term developed country, or advanced country, is used to categorize countries with developed economies in which the tertiary and quaternary sectors of industry dominate. Countries not fitting this definition may be referred to as developing countries.
This level of economic development usually translates into a high income per capita and a high Human Development Index (HDI). Countries with high gross domestic product (GDP) per capita often fit the above description of a developed economy. However, anomalies exist when determining "developed" status by the factor GDP per capita alone.
Synonyms
Modern terms synonymous with the term developed country or advanced country include industrialized country, more developed country (MDC), more economically developed country (MEDC), Global North country, 1st world country, and post-industrial country. The term industrialized country may be somewhat ambiguous, as industrialization is an ongoing process that is hard to define. The term MEDC is one used by modern geographers to specifically describe the status of the countries referred to: more economically developed. The first industrialised country was England, followed by Germany, France, the remainder of the United Kingdom and other Western European countries. According to economists such as Jeffrey Sachs, however, the current divide between the developed and developing world is largely a phenomenon of the 20th century.
Definition
Traditionally, Canada and the United States in North America, Japan in Asia, Australia and New Zealand in Oceania, and most countries in Northern Europe and Western Europe have been considered "developed countries". Additionally, Cyprus, Hong Kong, Israel, Malta, Singapore, Slovenia, South Korea, and Taiwan, are now widely regarded as "developed countries".
Hong Kong is a Special Administrative Region of the People's Republic of China, a developing country; however, it is a separate economic entity with its own currency and customs controls, and is recognized as developed. Taiwan has limited diplomatic recognition and is claimed by the People's Republic of China; however it functions as a de facto independent state, and is also recognized as developed.
In the old international reports, the countries of Eastern Europe (including Slovenia which still belongs to "Eastern Europe Group" in the UN institutions) as well as the former Soviet Union (U.S.S.R.) countries (including those in Asia) and Mongolia, were not included under either developed or developing regions, but rather were referred to as "countries in transition"; however they are now widely regarded as "developing countries" (except for Slovenia, see above).
Human Development Index
The UN HDI is a statistical measure that gauges a country's level of human development. While there is a strong correlation between having a high HDI score and a prosperous economy, the UN points out that the HDI accounts for more than income or productivity. Unlike GDP per capita or per capita income, the HDI takes into account how income is turned "into education and health opportunities and therefore into higher levels of human development." A few examples are Italy and the United States. Despite a relatively large difference in GDP per capita, both countries rank roughly equal in term of overall human development.[8] Since 1980, Norway (2001-2005), Japan (1991 and 1993), Canada (1985, 1992 and 1994-2000), Iceland (2006 and 2007) and Switzerland (1980) have had the highest HDI score. Countries with a score of over 0.800 are considered to have a "high" standard of human development. The top 30 countries have scores ranging from 0.894 in Brunei to 0.968 in Iceland. All countries included in the UN study on the IMF list had a high HDI. Several small countries, such as Andorra, Liechtenstein and Macau were not reviewed by the United Nations. Thus, these countries have not received an official HDI score.
All countries listed by IMF or CIA as "advanced" (as of 2007) - possess an HDI over 0.9 (as of 2004). All countriespossessing an HDI of 0.9 and over (as of 2004) - are also listed by IMF or CIA as "advanced" (as of 2007). Thus, all "advanced economies" (as of 2007) are characterized by an HDI score of 0.9 or higher (as of 2004).
This level of economic development usually translates into a high income per capita and a high Human Development Index (HDI). Countries with high gross domestic product (GDP) per capita often fit the above description of a developed economy. However, anomalies exist when determining "developed" status by the factor GDP per capita alone.
Synonyms
Modern terms synonymous with the term developed country or advanced country include industrialized country, more developed country (MDC), more economically developed country (MEDC), Global North country, 1st world country, and post-industrial country. The term industrialized country may be somewhat ambiguous, as industrialization is an ongoing process that is hard to define. The term MEDC is one used by modern geographers to specifically describe the status of the countries referred to: more economically developed. The first industrialised country was England, followed by Germany, France, the remainder of the United Kingdom and other Western European countries. According to economists such as Jeffrey Sachs, however, the current divide between the developed and developing world is largely a phenomenon of the 20th century.
Definition
Traditionally, Canada and the United States in North America, Japan in Asia, Australia and New Zealand in Oceania, and most countries in Northern Europe and Western Europe have been considered "developed countries". Additionally, Cyprus, Hong Kong, Israel, Malta, Singapore, Slovenia, South Korea, and Taiwan, are now widely regarded as "developed countries".
Hong Kong is a Special Administrative Region of the People's Republic of China, a developing country; however, it is a separate economic entity with its own currency and customs controls, and is recognized as developed. Taiwan has limited diplomatic recognition and is claimed by the People's Republic of China; however it functions as a de facto independent state, and is also recognized as developed.
In the old international reports, the countries of Eastern Europe (including Slovenia which still belongs to "Eastern Europe Group" in the UN institutions) as well as the former Soviet Union (U.S.S.R.) countries (including those in Asia) and Mongolia, were not included under either developed or developing regions, but rather were referred to as "countries in transition"; however they are now widely regarded as "developing countries" (except for Slovenia, see above).
Human Development Index
The UN HDI is a statistical measure that gauges a country's level of human development. While there is a strong correlation between having a high HDI score and a prosperous economy, the UN points out that the HDI accounts for more than income or productivity. Unlike GDP per capita or per capita income, the HDI takes into account how income is turned "into education and health opportunities and therefore into higher levels of human development." A few examples are Italy and the United States. Despite a relatively large difference in GDP per capita, both countries rank roughly equal in term of overall human development.[8] Since 1980, Norway (2001-2005), Japan (1991 and 1993), Canada (1985, 1992 and 1994-2000), Iceland (2006 and 2007) and Switzerland (1980) have had the highest HDI score. Countries with a score of over 0.800 are considered to have a "high" standard of human development. The top 30 countries have scores ranging from 0.894 in Brunei to 0.968 in Iceland. All countries included in the UN study on the IMF list had a high HDI. Several small countries, such as Andorra, Liechtenstein and Macau were not reviewed by the United Nations. Thus, these countries have not received an official HDI score.
All countries listed by IMF or CIA as "advanced" (as of 2007) - possess an HDI over 0.9 (as of 2004). All countriespossessing an HDI of 0.9 and over (as of 2004) - are also listed by IMF or CIA as "advanced" (as of 2007). Thus, all "advanced economies" (as of 2007) are characterized by an HDI score of 0.9 or higher (as of 2004).
District heating
District heating (less commonly called teleheating) is a system for distributing heat generated in a centralized location for residential and commercial heating requirements such as space heating and water heating. The heat is often obtained from a cogeneration plant burning fossil fuels but increasingly biomass, although heat-only boiler stations, geothermal heating and central solar heating are also used. District heating plants can provide higher efficiencies and better pollution control than localized boilers.
Heat generation
The core element of a district heating system is usually a cogeneration plant (also called combined heat and power, CHP) or a heat-only boiler station. Both have in common that they are typically based on combustion of primary energy carriers. The difference between the two systems is that, in a cogeneration plant, heat and electricity are generated simultaneously, whereas in heat-only boiler stations - as the name suggests - only heat is generated.
The combination of cogeneration and district heating is very energy efficient. A thermal power station which generates only electricity can convert less than approximately 50 % of the fuel input into electricity.[citation needed] The major part of the energy is wasted in form of heat and dissipated to the environment. A cogeneration plant recovers that heat and can reach total energy efficiency beyond 90 %.
Other heat sources for district heating systems can be geothermal heat, solar power, surplus heat from industrial processes, and nuclear power.
A cancelled Russian nuclear district heating plant in Fedyakovo, Nizhny Novgorod Oblast.
Nuclear energy has been suggested to be used for district heating. The principals for a conventional combination of cogeneration and district heating applies the same for nuclear as it does for any thermal power station. One use of nuclear heat generation was with the Ågesta Nuclear Power Plant in Sweden. In Switzerland, the Beznau Nuclear Power Plant provides heat to about 20,000 people.
Heat distribution
Insulated pipes to connect a new building to University of Warwick's campus-wide combined heat and power system.
After generation, the heat is distributed to the customer via a network of insulated pipes. District heating systems consists of feed and return lines. Usually the pipes are installed underground but there are also systems with overground pipes. Within the system heat storages may be installed to even out peak load demands.
The common medium used for heat distribution is water, but also steam is used. The advantage of steam is that in addition to heating purposes it can be used in industrial processes due to its higher temperature. The disadvantage of steam is a higher heat loss due to the high temperature. Also, the thermal efficiency of cogeneration plants is significantly lower if the cooling medium is high temperature steam, causing smaller electric power generation.
At customer level the heat network is connected to the central heating of the dwellings by heat exchangers (heat substations). The water (or the steam) used in the district heating system is not mixed with the water of the central heating system of the dwelling.
For the Norwegian district heating systems the yearly heat losses from distribution are about 10% of the total heat generated.
Pros and cons
District heating has various advantages compared to individual heating systems. Usually district heating is more energy efficient, due to simultaneous production of heat and electricity in combined heat and power generation plants. The larger combustion units also have a more advanced flue gas cleaning than single boiler systems. In the case of surplus heat from industries, district heating systems do not use additional fuel because they use heat (termed heat recovery) which would be disbursed to the environment.
District heating is a long-term commitment that fits poorly with a focus on short-term returns on investment. Benefits to the community include avoided costs of energy, through the use of surplus and wasted heat energy, and reduced investment in individual household or building heating equipment. District heating network, heat-only boiler stations, and cogeneration plants require high initial capital expenditure and financing. Only if considered as long-term investments these may translate into profitable operations for the owners of district heating systems, or combined heat and power plant operators. District heating is less attractive for areas with low population densities, as the investment per household is considerably higher.
Heat generation
The core element of a district heating system is usually a cogeneration plant (also called combined heat and power, CHP) or a heat-only boiler station. Both have in common that they are typically based on combustion of primary energy carriers. The difference between the two systems is that, in a cogeneration plant, heat and electricity are generated simultaneously, whereas in heat-only boiler stations - as the name suggests - only heat is generated.
The combination of cogeneration and district heating is very energy efficient. A thermal power station which generates only electricity can convert less than approximately 50 % of the fuel input into electricity.[citation needed] The major part of the energy is wasted in form of heat and dissipated to the environment. A cogeneration plant recovers that heat and can reach total energy efficiency beyond 90 %.
Other heat sources for district heating systems can be geothermal heat, solar power, surplus heat from industrial processes, and nuclear power.
A cancelled Russian nuclear district heating plant in Fedyakovo, Nizhny Novgorod Oblast.
Nuclear energy has been suggested to be used for district heating. The principals for a conventional combination of cogeneration and district heating applies the same for nuclear as it does for any thermal power station. One use of nuclear heat generation was with the Ågesta Nuclear Power Plant in Sweden. In Switzerland, the Beznau Nuclear Power Plant provides heat to about 20,000 people.
Heat distribution
Insulated pipes to connect a new building to University of Warwick's campus-wide combined heat and power system.
After generation, the heat is distributed to the customer via a network of insulated pipes. District heating systems consists of feed and return lines. Usually the pipes are installed underground but there are also systems with overground pipes. Within the system heat storages may be installed to even out peak load demands.
The common medium used for heat distribution is water, but also steam is used. The advantage of steam is that in addition to heating purposes it can be used in industrial processes due to its higher temperature. The disadvantage of steam is a higher heat loss due to the high temperature. Also, the thermal efficiency of cogeneration plants is significantly lower if the cooling medium is high temperature steam, causing smaller electric power generation.
At customer level the heat network is connected to the central heating of the dwellings by heat exchangers (heat substations). The water (or the steam) used in the district heating system is not mixed with the water of the central heating system of the dwelling.
For the Norwegian district heating systems the yearly heat losses from distribution are about 10% of the total heat generated.
Pros and cons
District heating has various advantages compared to individual heating systems. Usually district heating is more energy efficient, due to simultaneous production of heat and electricity in combined heat and power generation plants. The larger combustion units also have a more advanced flue gas cleaning than single boiler systems. In the case of surplus heat from industries, district heating systems do not use additional fuel because they use heat (termed heat recovery) which would be disbursed to the environment.
District heating is a long-term commitment that fits poorly with a focus on short-term returns on investment. Benefits to the community include avoided costs of energy, through the use of surplus and wasted heat energy, and reduced investment in individual household or building heating equipment. District heating network, heat-only boiler stations, and cogeneration plants require high initial capital expenditure and financing. Only if considered as long-term investments these may translate into profitable operations for the owners of district heating systems, or combined heat and power plant operators. District heating is less attractive for areas with low population densities, as the investment per household is considerably higher.
Drought
A drought is an extended period of months or years when a region notes a deficiency in its water supply. Generally, this occurs when a region receives consistently below average precipitation. It can have a substantial impact on the ecosystem and agriculture of the affected region. Although droughts can persist for several years, even a short, intense drought can cause significant damage and harm the local economy. This global phenomenon has a widespread impact on agriculture. The United Nations estimates that an area of fertile soil the size of Ukraine is lost every year because of drought, deforestation, and climate instability. Lengthy periods of drought have triggered mass migration in Africa in this last decade and in various other parts of the world for thousands of years.
Implications
Drought is a normal, recurring feature of the climate in most parts of the world. It is among the earliest documented climatic events, present in the Epic of Gilgamesh and tied to the biblical story of Joesph's arrival in and the later Exodus from Ancient Egypt. Hunter-gatherer migrations in 9,500BC Chile have been linked to the phenomenon, as has the exodus of early man out of Africa and into the rest of the world around 135,000 years ago. Modern peoples can effectively mitigate much of the impact of drought through irrigation and crop rotation. Failure to develop adequate drought mitigation strategies carries a grave human cost in the modern era, exacerbated by ever-increasing population densities. Recurring droughts leading to desertification in the Horn of Africa have created grave ecological catastrophes, prompting massive food shortages, still recurring. To the north-west of the Horn, the Darfur conflict in neighboring Sudan, also affecting Chad, was fueled by decades of drought; combination of drought, desertification and overpopulation are among the causes of the Darfur conflict, because the Arab Baggara nomads searching for water have to take their livestock further south, to land mainly occupied by non-Arab farming peoples.
According to a UN climate report, the Himalayan glaciers that are the sources of Asia's biggest rivers - Ganges, Indus, Brahmaputra, Yangtze, Mekong, Salween and Yellow - could disappear by 2035 due to global warming. Approximately 2.4 billion people live in the drainage basin of the Himalayan rivers. India, China, Pakistan, Bangladesh, Nepal and Myanmar could experience floods followed by droughts in coming decades. Drought in India affecting the Ganges is of particular concern, as it provides drinking water and agricultural irrigation for more than 500 million people. The west coast of North America, which gets much of its water from glaciers in mountain ranges such as the Rocky Mountains and Sierra Nevada, also would be affected.
In 2005, parts of the Amazon basin experienced the worst drought in 100 years. A 23 July 2006 article reported Woods Hole Research Center results showing that the forest in its present form could survive only three years of drought. Scientists at the Brazilian National Institute of Amazonian Research argue in the article that this drought response, coupled with the effects of deforestation on regional climate, are pushing the rainforest towards a "tipping point" where it would irreversibly start to die. It concludes that the rainforest is on the brink of being turned into savanna or desert, with catastrophic consequences for the world's climate. According to the WWF, the combination of climate change and deforestation increases the drying effect of dead trees that fuels forest fires.
By far the largest part of Australia is desert or semi-arid lands commonly known as the outback. A 2005 study by Australian and American researchers investigated the desertification of the interior, and suggested that one explanation was related to human settlers who arrived about 50,000 years ago. Regular burning by these settlers could have prevented monsoons from reaching interior Australia. In June 2008 it became known that an expert panel had warned of long term, maybe irreversible, severe ecological damage for the whole Murray-Darling basin if it does not receive sufficient water by October. Australia could experience more severe droughts and they could become more frequent in the future, a government-commissioned report said on July 6, 2008. The Australian of the year 2007, environmentalist Tim Flannery, predicted that unless it made drastic changes, Perth in Western Australia could become the world’s first ghost metropolis, an abandoned city with no more water to sustain its population.
Causes
Generally, rainfall is related to the amount of water vapor in the atmosphere, combined with the upward forcing of the air mass containing that water vapor. If either of these are reduced,the result is a drought. This can be triggered by an above average prevalence of high pressure systems, winds carrying continental, rather than oceanic air masses (ie. reduced water content), and ridges of high pressure areas form with behaviors which prevent or restrict the developing of thunderstorm activity or rainfall over one certain region. Oceanic and atmospheric weather cycles such as the El Niño-Southern Oscillation (ENSO) make drought a regular recurring feature of the Americas along the Pacific coast and Australia. Guns, Germs, and Steel author Jared Diamond sees the stark impact of the multi-year ENSO cycles on Australian weather patterns as a key reason that Australian aborigines remained a hunter-gatherer society rather than adopting agriculture.
Human activity can directly trigger exacerbating factors such as overfarming, excessive irrigation, Deforestation, and erosion adversely impact the ability of the land to capture and hold water. While these tend to be relatively isolated in their scope, activities resulting in climate change are expected to trigger droughts with a substantial impact on agriculture throughout the world, and especially in developing nations. Paradoxically, some proposed short-term solutions to global warming also carry with them increased chances of drought.
Consequences
Periods of drought can have significant environmental, agricultural, health, economic and social consequences. The effect varies according to vulnerability. For example, subsistence farmers are more likely to migrate during drought because they do not have alternative food sources. Areas with populations that depend on subsistence farming as a major food source are more vulnerable to drought-triggered famine. Drought is rarely if ever the sole cause of famine; socio-political factors such as extreme widespread poverty play a major role. Drought can also reduce water quality, because lower water flows reduce dilution of pollutants and increase contamination of remaining water sources. A few common consequences of drought include:
* Diminished crop growth or yield productions and carrying capacity for livestock;
* Wildfires, such as Australian bushfires, are more common during times of drought;
* Shortages of water for industrial users;
* Dust storms, when drought hits an area suffering from desertification and erosion;
* Malnutrition, dehydration and related diseases;
* Famine due to lack of water for irrigation;
* Social unrest;
* Mass migration, resulting in internal displacement and international refugees;
* War over natural resources, including water and food;
* Reduced electricity production due to insufficient available coolant for power stations; and reduced water flow through hydroelectric dams.
* Snakes migration and increases in snakebites;
* Creates windblown dust bowls which erodes the landscape, Damages terrestrial and aquatic wildlife habitat.
Stages of drought
As a drought persists, the conditions surrounding it gradually worsen and its impact on the local population gradually increases. Droughts go through three stages before their ultimate cessation:
1. Meteorological drought is brought about when there is a prolonged period with less than average precipitation. Meteorological drought usually precedes the other kinds of drought.
2. Agricultural droughts are droughts that affect crop production or the ecology of the range. This condition can also arise independently from any change in precipitation levels when soil conditions and erosion triggered by poorly planned agricultural endeavors cause a shortfall in water available to the crops. However, in a traditional drought, it is caused by an extended period of below average precipitation.
3. Hydrological drought is brought about when the water reserves available in sources such as aquifers, lakes and reservoirs falls below the statistical average. Like an agricultural drought, this can be triggered by more than just a loss of rainfall. For instance, Kazakhstan was recently awarded a large amount of money by the World Bank to restore water that had been diverted to other nations from the Aral Sea under Soviet rule. Similar circumstances also place their largest lake, Balkhash, at risk of completely drying out.
Drought mitigation strategies
* Desalination of sea water for irrigation or consumption.
* Drought monitoring - Continuous observation of rainfall levels and comparisons with current usage levels can help prevent man-made drought. For instance, analysis of water usage in Yemen has revealed that their water table (underground water level) is put at grave risk by over-use to fertilize their Khat crop. Careful monitoring of moisture levels can also help predict increased risk for wildfires, using such metrics as the Keetch-Byram Drought Index or Palmer Drought Index.
* Land use - Carefully planned crop rotation can help to minimize erosion and allow farmers to plant less water-dependent crops in drier years.
* Rainwater harvesting - Collection and storage of rainwater from roofs or other suitable catchments.
* Recycled water - Former wastewater (sewage) that has been treated and purified for reuse.
* Transvasement - Building canals or redirecting rivers as massive attempts at irrigation in drought-prone areas.
* Water restrictions - Water use may be regulated (particularly outdoors). This may involve regulating the use of sprinklers, hoses or buckets on outdoor plants, the washing of motor vehicles or other outdoor hard surfaces (including roofs and paths), topping up of swimming pools, and also the fitting of water conservation devices inside the home (including shower heads, taps and dual flush toilets).
* Cloud seeding - an artificial technique to induce rainfall.
Implications
Drought is a normal, recurring feature of the climate in most parts of the world. It is among the earliest documented climatic events, present in the Epic of Gilgamesh and tied to the biblical story of Joesph's arrival in and the later Exodus from Ancient Egypt. Hunter-gatherer migrations in 9,500BC Chile have been linked to the phenomenon, as has the exodus of early man out of Africa and into the rest of the world around 135,000 years ago. Modern peoples can effectively mitigate much of the impact of drought through irrigation and crop rotation. Failure to develop adequate drought mitigation strategies carries a grave human cost in the modern era, exacerbated by ever-increasing population densities. Recurring droughts leading to desertification in the Horn of Africa have created grave ecological catastrophes, prompting massive food shortages, still recurring. To the north-west of the Horn, the Darfur conflict in neighboring Sudan, also affecting Chad, was fueled by decades of drought; combination of drought, desertification and overpopulation are among the causes of the Darfur conflict, because the Arab Baggara nomads searching for water have to take their livestock further south, to land mainly occupied by non-Arab farming peoples.
According to a UN climate report, the Himalayan glaciers that are the sources of Asia's biggest rivers - Ganges, Indus, Brahmaputra, Yangtze, Mekong, Salween and Yellow - could disappear by 2035 due to global warming. Approximately 2.4 billion people live in the drainage basin of the Himalayan rivers. India, China, Pakistan, Bangladesh, Nepal and Myanmar could experience floods followed by droughts in coming decades. Drought in India affecting the Ganges is of particular concern, as it provides drinking water and agricultural irrigation for more than 500 million people. The west coast of North America, which gets much of its water from glaciers in mountain ranges such as the Rocky Mountains and Sierra Nevada, also would be affected.
In 2005, parts of the Amazon basin experienced the worst drought in 100 years. A 23 July 2006 article reported Woods Hole Research Center results showing that the forest in its present form could survive only three years of drought. Scientists at the Brazilian National Institute of Amazonian Research argue in the article that this drought response, coupled with the effects of deforestation on regional climate, are pushing the rainforest towards a "tipping point" where it would irreversibly start to die. It concludes that the rainforest is on the brink of being turned into savanna or desert, with catastrophic consequences for the world's climate. According to the WWF, the combination of climate change and deforestation increases the drying effect of dead trees that fuels forest fires.
By far the largest part of Australia is desert or semi-arid lands commonly known as the outback. A 2005 study by Australian and American researchers investigated the desertification of the interior, and suggested that one explanation was related to human settlers who arrived about 50,000 years ago. Regular burning by these settlers could have prevented monsoons from reaching interior Australia. In June 2008 it became known that an expert panel had warned of long term, maybe irreversible, severe ecological damage for the whole Murray-Darling basin if it does not receive sufficient water by October. Australia could experience more severe droughts and they could become more frequent in the future, a government-commissioned report said on July 6, 2008. The Australian of the year 2007, environmentalist Tim Flannery, predicted that unless it made drastic changes, Perth in Western Australia could become the world’s first ghost metropolis, an abandoned city with no more water to sustain its population.
Causes
Generally, rainfall is related to the amount of water vapor in the atmosphere, combined with the upward forcing of the air mass containing that water vapor. If either of these are reduced,the result is a drought. This can be triggered by an above average prevalence of high pressure systems, winds carrying continental, rather than oceanic air masses (ie. reduced water content), and ridges of high pressure areas form with behaviors which prevent or restrict the developing of thunderstorm activity or rainfall over one certain region. Oceanic and atmospheric weather cycles such as the El Niño-Southern Oscillation (ENSO) make drought a regular recurring feature of the Americas along the Pacific coast and Australia. Guns, Germs, and Steel author Jared Diamond sees the stark impact of the multi-year ENSO cycles on Australian weather patterns as a key reason that Australian aborigines remained a hunter-gatherer society rather than adopting agriculture.
Human activity can directly trigger exacerbating factors such as overfarming, excessive irrigation, Deforestation, and erosion adversely impact the ability of the land to capture and hold water. While these tend to be relatively isolated in their scope, activities resulting in climate change are expected to trigger droughts with a substantial impact on agriculture throughout the world, and especially in developing nations. Paradoxically, some proposed short-term solutions to global warming also carry with them increased chances of drought.
Consequences
Periods of drought can have significant environmental, agricultural, health, economic and social consequences. The effect varies according to vulnerability. For example, subsistence farmers are more likely to migrate during drought because they do not have alternative food sources. Areas with populations that depend on subsistence farming as a major food source are more vulnerable to drought-triggered famine. Drought is rarely if ever the sole cause of famine; socio-political factors such as extreme widespread poverty play a major role. Drought can also reduce water quality, because lower water flows reduce dilution of pollutants and increase contamination of remaining water sources. A few common consequences of drought include:
* Diminished crop growth or yield productions and carrying capacity for livestock;
* Wildfires, such as Australian bushfires, are more common during times of drought;
* Shortages of water for industrial users;
* Dust storms, when drought hits an area suffering from desertification and erosion;
* Malnutrition, dehydration and related diseases;
* Famine due to lack of water for irrigation;
* Social unrest;
* Mass migration, resulting in internal displacement and international refugees;
* War over natural resources, including water and food;
* Reduced electricity production due to insufficient available coolant for power stations; and reduced water flow through hydroelectric dams.
* Snakes migration and increases in snakebites;
* Creates windblown dust bowls which erodes the landscape, Damages terrestrial and aquatic wildlife habitat.
Stages of drought
As a drought persists, the conditions surrounding it gradually worsen and its impact on the local population gradually increases. Droughts go through three stages before their ultimate cessation:
1. Meteorological drought is brought about when there is a prolonged period with less than average precipitation. Meteorological drought usually precedes the other kinds of drought.
2. Agricultural droughts are droughts that affect crop production or the ecology of the range. This condition can also arise independently from any change in precipitation levels when soil conditions and erosion triggered by poorly planned agricultural endeavors cause a shortfall in water available to the crops. However, in a traditional drought, it is caused by an extended period of below average precipitation.
3. Hydrological drought is brought about when the water reserves available in sources such as aquifers, lakes and reservoirs falls below the statistical average. Like an agricultural drought, this can be triggered by more than just a loss of rainfall. For instance, Kazakhstan was recently awarded a large amount of money by the World Bank to restore water that had been diverted to other nations from the Aral Sea under Soviet rule. Similar circumstances also place their largest lake, Balkhash, at risk of completely drying out.
Drought mitigation strategies
* Desalination of sea water for irrigation or consumption.
* Drought monitoring - Continuous observation of rainfall levels and comparisons with current usage levels can help prevent man-made drought. For instance, analysis of water usage in Yemen has revealed that their water table (underground water level) is put at grave risk by over-use to fertilize their Khat crop. Careful monitoring of moisture levels can also help predict increased risk for wildfires, using such metrics as the Keetch-Byram Drought Index or Palmer Drought Index.
* Land use - Carefully planned crop rotation can help to minimize erosion and allow farmers to plant less water-dependent crops in drier years.
* Rainwater harvesting - Collection and storage of rainwater from roofs or other suitable catchments.
* Recycled water - Former wastewater (sewage) that has been treated and purified for reuse.
* Transvasement - Building canals or redirecting rivers as massive attempts at irrigation in drought-prone areas.
* Water restrictions - Water use may be regulated (particularly outdoors). This may involve regulating the use of sprinklers, hoses or buckets on outdoor plants, the washing of motor vehicles or other outdoor hard surfaces (including roofs and paths), topping up of swimming pools, and also the fitting of water conservation devices inside the home (including shower heads, taps and dual flush toilets).
* Cloud seeding - an artificial technique to induce rainfall.
Drinking water
Drinking water is water that is of sufficiently high quality that it can be drunk without risk of immediate or long term harm. Such water is commonly called potable water. In most developed countries the water supplied to households, commerce and industry is all of Drinking water standard even though only a very small proportion is actually drunk or used in food preparation.
Over large parts of the world, humans drink water that contains disease vectors or pathogens or contain unacceptable levels of dissolved contaminants or solids in suspension. Such waters are not potable water and drinking such waters or using them in cooking leads to widespread acute and chronic illness and is a major cause of death in many countries.
Typically, water supply networks deliver potable water, whether it is to be used for drinking, washing or landscape irrigation. One counterexample is urban China, where drinking water can optionally be delivered by a separate tap.
Globe icon
Throughout most of the world the most common contamination of raw water sources is from human sewage and in particular human faecal pathogens and parasites. In 2006, waterborne diseases were estimated to cause 1.8 million deaths each year while about 1.1 billion people lacked proper drinking water.. It is clear that people in the developing world need to have access to good quality water in sufficient quantity, purification technology and availability and distribution systems for water. In many parts of the world the only sources of water are from small streams often directly contaminated by sewage. However, even where wells are used this does not eliminate the risk of contamination .
Most water requires some type of treatment before use, even water from deep wells or springs. The extent of treatment depends on the source of the water. Appropriate technology options in water treatment include both community-scale and household-scale point-of-use (POU) designs.
The most reliable way to kill microbial pathogenic agents is to heat water to a rolling boil but this requires abundant sources of fuel and is very onerous on the households especially where it is difficult to store boiled water in sterile conditions. Other techniques, such as varying forms of filtration, chemical disinfection, and exposure to ultraviolet radiation (including solar UV) have been demonstrated in an array of randomized control trials to significantly reduce levels of water-borne disease among users in low-income countries.
Over the past decade, an increasing number of field-based studies have been undertaken to determine the success of POU measures in reducing waterborne disease. The ability of POU options to reduce disease is a function of both their ability to remove microbial pathogens if properly applied and such social factors as ease of use and cultural appropriateness. Technologies may generate more (or less) health benefit than their lab-based microbial removal performance would suggest.
The current priority of the proponents of POU treatment is to reach large numbers of low-income households on a sustainable basis. Few POU measures have reached significant scale thus far, but efforts to promote and commercially distribute these products to the world's poor have only been under way for a few years.
Parameters for drinking water quality typically fall under two categories: chemical/physical and microbiological. Chemical/physical parameters include heavy metals, trace organic compounds, total suspended solids (TSS), and turbidity. Microbiological parameters include Coliform bacteria, E. coli, and specific pathogenic species of bacteria (such as cholera-causing Vibrio cholerae), viruses, and protozoan parasites.
Chemical parameters tend to pose more of a chronic health risk through buildup of heavy metals although some components like nitrates/nitrites and arsenic may have a more immediate impact. Physical parameters affect the aesthetics and taste of the drinking water and may complicate the removal of microbial pathogens.
Originally, fecal contamination was determined with the presence of coliform bacteria, a convenient marker for a class of harmful fecal pathogens. The presence of fecal coliforms (like E. Coli) serves as an indication of contamination by sewage. Additional contaminants include protozoan oocysts such as Cryptosporidium sp., Giardia lambia, Legionella, and viruses (enteric). Microbial pathogenic parameters are typically of greatest concern because of their immediate health risk.
Access to drinking water
Only forty-six percent of people in Africa have safe drinking water.
Drinking water vending machines in Thailand. One litre of purified water is sold (into the customer's own bottle) for 1 baht
Earth's surface consists of 70% water. Water is available almost everywhere if proper methods are used to get it. Sources where water may be obtained include:
* ground sources such as groundwater, hyporheic zones and aquifers.
* precipitation which includes rain, hail, snow, fog, etc.
* surface water such as rivers, streams, glaciers
* biological sources such as plants.
* the sea through de-salination
As a country’s economy becomes richer, a larger percentage of its people tend to have access to drinking water and sanitation. Access to drinking water is measured by the number of people who have a reasonable means of getting an adequate amount of water that is safe for drinking, washing, and essential household activities.
As of the year 2006 (and pre-existing for at least three decades), there is a substantial shortfall in availability of potable water in less developed countries, principally because of migration from the countryside to urban areas in countries with low average rainfall and limited infrastructure. As of the year 2000, 27 percent of the populations of lesser developed countries did not have access to safe drinking water[6]. Implications for disease propagation are significant. Many nations have water quality regulations for water sold as drinking water, although these are often not strictly enforced outside of the developed world. The World Health Organization sets international standards for drinking water. A broad classification of drinking water safety worldwide can be found in Safe Water for International Travellers.
It reflects the health of a country’s people and the country’s capacity to collect, clean, and distribute water to consumers. According to the United Nations' World Health Organization (WHO) more than one billion people in low and middle-income countries lack access to safe water for drinking, personal hygiene and domestic use. These numbers represent more than 20 percent of the world’s people. In addition, close to 3 billion people did not have access to adequate sanitation facilities. (For details see data on the website of the Joint Monitoring Programme (JMP) on water and sanitation of WHO and UNICEF.)
While the occurrence of waterborne diseases in developed countries is generally low due to a generally good system of water treatment, distribution and monitoring, waterborne diseases are among the leading causes of morbidity and mortality in low- and middle-income countries, frequently called developing countries.
The main reason for poor access to safe water is the inability to finance and to adequately maintain the necessary infrastructure. Overpopulation and scarcity of water resources are contributing factors.
Many other countries also lack in the amount of safe drinking water that they need to survive. Some of the countries have less than twenty percent of the population that has access to safe drinking water. For example in Africa, with more than 700 million people, only forty-six percent of people have safe drinking water. The more populous Asia Pacific region with over three billion people, eighty percent of whom with access to drinking water, still leaves over 600 million people without access to safe drinking water.
The lack of water and the lack of hygiene is one of the biggest problems that many poor countries have encountered in progressing their way of living. The problem has reached such endemic proportions that 2.2 million deaths per annum occur from unsanitary water - ninety percent of these are children under the age of five. One program developed to help people gain access to safe drinking water is the Water Aid program. Working in 17 countries to help provide water, Water Aid is useful in helping the sanitation and hygiene education to some of the world's poorest people. Solar water disinfection is a low-cost method of purifying water that can often be implemented with locally available materials. Unlike methods that rely on firewood, it has low impact on the environment.
In the US, the typical nonconserving single family home uses 69.3 gallons of water per capita per day. These figures are concerning in some parts of the country where water supplies are dangerously low due to drought, particularly in the West and the South East region of the U.S .
Over large parts of the world, humans drink water that contains disease vectors or pathogens or contain unacceptable levels of dissolved contaminants or solids in suspension. Such waters are not potable water and drinking such waters or using them in cooking leads to widespread acute and chronic illness and is a major cause of death in many countries.
Typically, water supply networks deliver potable water, whether it is to be used for drinking, washing or landscape irrigation. One counterexample is urban China, where drinking water can optionally be delivered by a separate tap.
Globe icon
Throughout most of the world the most common contamination of raw water sources is from human sewage and in particular human faecal pathogens and parasites. In 2006, waterborne diseases were estimated to cause 1.8 million deaths each year while about 1.1 billion people lacked proper drinking water.. It is clear that people in the developing world need to have access to good quality water in sufficient quantity, purification technology and availability and distribution systems for water. In many parts of the world the only sources of water are from small streams often directly contaminated by sewage. However, even where wells are used this does not eliminate the risk of contamination .
Most water requires some type of treatment before use, even water from deep wells or springs. The extent of treatment depends on the source of the water. Appropriate technology options in water treatment include both community-scale and household-scale point-of-use (POU) designs.
The most reliable way to kill microbial pathogenic agents is to heat water to a rolling boil but this requires abundant sources of fuel and is very onerous on the households especially where it is difficult to store boiled water in sterile conditions. Other techniques, such as varying forms of filtration, chemical disinfection, and exposure to ultraviolet radiation (including solar UV) have been demonstrated in an array of randomized control trials to significantly reduce levels of water-borne disease among users in low-income countries.
Over the past decade, an increasing number of field-based studies have been undertaken to determine the success of POU measures in reducing waterborne disease. The ability of POU options to reduce disease is a function of both their ability to remove microbial pathogens if properly applied and such social factors as ease of use and cultural appropriateness. Technologies may generate more (or less) health benefit than their lab-based microbial removal performance would suggest.
The current priority of the proponents of POU treatment is to reach large numbers of low-income households on a sustainable basis. Few POU measures have reached significant scale thus far, but efforts to promote and commercially distribute these products to the world's poor have only been under way for a few years.
Parameters for drinking water quality typically fall under two categories: chemical/physical and microbiological. Chemical/physical parameters include heavy metals, trace organic compounds, total suspended solids (TSS), and turbidity. Microbiological parameters include Coliform bacteria, E. coli, and specific pathogenic species of bacteria (such as cholera-causing Vibrio cholerae), viruses, and protozoan parasites.
Chemical parameters tend to pose more of a chronic health risk through buildup of heavy metals although some components like nitrates/nitrites and arsenic may have a more immediate impact. Physical parameters affect the aesthetics and taste of the drinking water and may complicate the removal of microbial pathogens.
Originally, fecal contamination was determined with the presence of coliform bacteria, a convenient marker for a class of harmful fecal pathogens. The presence of fecal coliforms (like E. Coli) serves as an indication of contamination by sewage. Additional contaminants include protozoan oocysts such as Cryptosporidium sp., Giardia lambia, Legionella, and viruses (enteric). Microbial pathogenic parameters are typically of greatest concern because of their immediate health risk.
Access to drinking water
Only forty-six percent of people in Africa have safe drinking water.
Drinking water vending machines in Thailand. One litre of purified water is sold (into the customer's own bottle) for 1 baht
Earth's surface consists of 70% water. Water is available almost everywhere if proper methods are used to get it. Sources where water may be obtained include:
* ground sources such as groundwater, hyporheic zones and aquifers.
* precipitation which includes rain, hail, snow, fog, etc.
* surface water such as rivers, streams, glaciers
* biological sources such as plants.
* the sea through de-salination
As a country’s economy becomes richer, a larger percentage of its people tend to have access to drinking water and sanitation. Access to drinking water is measured by the number of people who have a reasonable means of getting an adequate amount of water that is safe for drinking, washing, and essential household activities.
As of the year 2006 (and pre-existing for at least three decades), there is a substantial shortfall in availability of potable water in less developed countries, principally because of migration from the countryside to urban areas in countries with low average rainfall and limited infrastructure. As of the year 2000, 27 percent of the populations of lesser developed countries did not have access to safe drinking water[6]. Implications for disease propagation are significant. Many nations have water quality regulations for water sold as drinking water, although these are often not strictly enforced outside of the developed world. The World Health Organization sets international standards for drinking water. A broad classification of drinking water safety worldwide can be found in Safe Water for International Travellers.
It reflects the health of a country’s people and the country’s capacity to collect, clean, and distribute water to consumers. According to the United Nations' World Health Organization (WHO) more than one billion people in low and middle-income countries lack access to safe water for drinking, personal hygiene and domestic use. These numbers represent more than 20 percent of the world’s people. In addition, close to 3 billion people did not have access to adequate sanitation facilities. (For details see data on the website of the Joint Monitoring Programme (JMP) on water and sanitation of WHO and UNICEF.)
While the occurrence of waterborne diseases in developed countries is generally low due to a generally good system of water treatment, distribution and monitoring, waterborne diseases are among the leading causes of morbidity and mortality in low- and middle-income countries, frequently called developing countries.
The main reason for poor access to safe water is the inability to finance and to adequately maintain the necessary infrastructure. Overpopulation and scarcity of water resources are contributing factors.
Many other countries also lack in the amount of safe drinking water that they need to survive. Some of the countries have less than twenty percent of the population that has access to safe drinking water. For example in Africa, with more than 700 million people, only forty-six percent of people have safe drinking water. The more populous Asia Pacific region with over three billion people, eighty percent of whom with access to drinking water, still leaves over 600 million people without access to safe drinking water.
The lack of water and the lack of hygiene is one of the biggest problems that many poor countries have encountered in progressing their way of living. The problem has reached such endemic proportions that 2.2 million deaths per annum occur from unsanitary water - ninety percent of these are children under the age of five. One program developed to help people gain access to safe drinking water is the Water Aid program. Working in 17 countries to help provide water, Water Aid is useful in helping the sanitation and hygiene education to some of the world's poorest people. Solar water disinfection is a low-cost method of purifying water that can often be implemented with locally available materials. Unlike methods that rely on firewood, it has low impact on the environment.
In the US, the typical nonconserving single family home uses 69.3 gallons of water per capita per day. These figures are concerning in some parts of the country where water supplies are dangerously low due to drought, particularly in the West and the South East region of the U.S .
Earth Charter
The Earth Charter is a declaration of fundamental values and principles from Earth Charter International that it considers as necessary for building a just, sustainable, and peaceful global society in the 21st century. Created by a large global consultation process, and endorsed by thousands of organizations representing millions of individuals, the Charter's stated purpose is to inspire in all peoples a sense of global interdependence and shared responsibility for the well-being of the human family and the larger living world. It calls upon humanity to help create a global partnership at a critical juncture in history. The Earth Charter's ethical vision proposes that environmental protection, human rights, equitable human development, and peace are interdependent and indivisible. The Charter claims to provide a new framework for thinking about and addressing these issues.
History
The idea of a Charter originated in 1987, when the United Nations World Commission on Environment and Development called for a new charter to guide the transition to sustainable development. In 1992, the need for a charter was urged by then-Secretary General Boutros Boutros-Ghali at the Rio de Janeiro Earth Summit, but the time for such a declaration was not right. The Rio Declaration became the statement of the achievable consensus at that time. In 1994, Maurice Strong (Chairman of the Earth Summit) and Mikhail Gorbachev, working through organizations they each founded (Earth Council and Green Cross International respectively), restarted the Earth Charter as a civil society initiative, with the help of the Government of the Netherlands. The initial drafting and consultation process drew on hundreds of international documents.
Drafting of the Charter
The Earth Charter was created through an open and participatory worldwide consultation process.[citation needed] Many thousands of people and hundreds of organizations contributed to the drafting process. The drafting of the text was overseen by the independent Earth Charter Commission, which was convened by Maurice Strong and Mikhail Gorbachev with the purpose of developing a global consensus on values and principles for a sustainable future. The Commission continues to serve as the steward of the Earth Charter text.
The Earth Charter was completed in March 2000 and launched in a special ceremony at The Peace Palace in The Hague, Netherlands, on 29 June 2000. Queen Beatrix of the Netherlands attended the ceremony. The Charter has since then been formally endorsed by thousands of organizations representing millions of people, including the UNESCO Conference of Member States, the World Conservation Union of IUCN, national government ministries, national and international associations of universities, and hundreds of cities and towns in dozens of countries. It has also been endorsed by tens of thousands of individuals, and publicly supported by numerous heads of state.
Preamble to the Earth Charter
“ We stand at a critical moment in Earth's history, a time when humanity must choose its future. As the world becomes increasingly interdependent and fragile, the future at once holds great peril and great promise. To move forward we must recognize that in the midst of a magnificent diversity of cultures and life forms we are one human family and one Earth community with a common destiny. We must join together to bring forth a sustainable global society founded on respect for nature, universal human rights, economic justice, and a culture of peace. Towards this end, it is imperative that we, the peoples of Earth, declare our responsibility to one another, to the greater community of life, and to future generations. ”
General Principles
The Earth Charter urges environmental responsibility, peaceful coexistence, respect for life, democracy, and justice. It is organized into 16 general headings, each covering a general principle, as follows:
1. Respect Earth and life in all its diversity.
2. Care for the community of life with understanding, compassion and love.
3. Build democratic societies that are just, participatory, sustainable and peaceful.
4. Secure Earth's bounty and beauty for present and future generations.
5. Protect and restore the integrity of Earth's ecological systems, with special concern for biological diversity and the natural processes that sustain life.
6. Prevent harm as the best method of environmental protection and, when knowledge is limited, apply a precautionary approach.
7. Adopt patterns of production, consumption and reproduction that safeguard Earth's regenerative capacities, human rights and community well-being.
8. Advance the study of ecological sustainability and promote the open exchange and wide application of the knowledge acquired.
9. Eradicate poverty as an ethical, social and environmental imperative.
10. Ensure that economic activities and institutions at all levels promote human development in an equitable and sustainable manner.
11. Affirm gender equality and equity as prerequisites to sustainable development and ensure universal access to education, health care and economic opportunity.
12. Uphold the right of all, without discrimination, to a natural and social environment supportive of human dignity, bodily health and spiritual well-being, with special attention to the rights of indigenous peoples and minorities.
13. Strengthen democratic institutions at all levels, and provide transparency and accountability in governance, inclusive participation in decision-making, and access to justice.
14. Integrate into formal education and lifelong learning the knowledge, values and skills needed for a sustainable way of life.
15. Treat all living beings with respect and consideration.
16. Promote a culture of tolerance, nonviolence and peace.
Reaction
The Earth Charter has been publicly endorsed, recognized, or supported by people and organizations across a wide range of the political spectrum, from conservative to liberal, as well as from all major religious traditions. has received support from business corporations, grassroots activists, universities, governments, and global non-governmental organizations. Overall, reaction to the document can be characterized as overwhelmingly positive.
However, the Charter has also received opposition from many groups and governments. For example, in the United States and other countries, members of religious groups, such as the Religious Right have objected to the document on the grounds that it is secular, and espouses socialism. Some groups go so far as to complain that it contains no reference to the doctrines of Judeo-Christianity.[citation needed] In addition, some conservatives cite an informal comment by Mikhail Gorbachev that the document is "a kind of Ten Commandments", and point to the fact that at the 2002 World Summit on Sustainable Development in Johannesburg, South Africa, a copy of the document was placed symbolically in an "Ark of Hope" -- an independent project by the American artist Sally Linder. Some members of the American Religious Right infer from these incidents that the Charter is a proposed replacement for the Ten Commandments, and part of a conspiracy to establish a New World Government that replaces National Sovereignty.
Earth Charter International, the organization responsible for promoting the Charter, argues in its literature that the Earth Charter is respectful and inclusive of all religious traditions. They state that the Charter itself makes no statements to support these claims of intent to supplant any of the world's religions or to create a world government. In their opinion, the Charter is simply a statement of common ethical values that recognises humanity's shared responsibility to the Earth and to each other. It is similar, in this respect, to the work of Jacques Maritain, who discovered that all human beings could agree on basic values, regardless of the many disparate beliefs that backed them.
Some Libertarians also express numerous critiques of the Charter, including a concern that the Charter's language calling for 'economic justice' is equivalent to espousing socialism. But the Charter's leadership has stated that it does not adhere to any specific political ideology, and support for the Earth Charter has come from both traditionally "left" and "right"-leaning political leaders, in many countries.
Earth Charter Youth Initiative
The Earth Charter Youth Initiative (ECYI) (http://www.earthcharterinaction.org/youth/) is a network of young activists, youth NGOs, and partners who share a common interest in sustainable development and the Earth Charter.
History
The idea of a Charter originated in 1987, when the United Nations World Commission on Environment and Development called for a new charter to guide the transition to sustainable development. In 1992, the need for a charter was urged by then-Secretary General Boutros Boutros-Ghali at the Rio de Janeiro Earth Summit, but the time for such a declaration was not right. The Rio Declaration became the statement of the achievable consensus at that time. In 1994, Maurice Strong (Chairman of the Earth Summit) and Mikhail Gorbachev, working through organizations they each founded (Earth Council and Green Cross International respectively), restarted the Earth Charter as a civil society initiative, with the help of the Government of the Netherlands. The initial drafting and consultation process drew on hundreds of international documents.
Drafting of the Charter
The Earth Charter was created through an open and participatory worldwide consultation process.[citation needed] Many thousands of people and hundreds of organizations contributed to the drafting process. The drafting of the text was overseen by the independent Earth Charter Commission, which was convened by Maurice Strong and Mikhail Gorbachev with the purpose of developing a global consensus on values and principles for a sustainable future. The Commission continues to serve as the steward of the Earth Charter text.
The Earth Charter was completed in March 2000 and launched in a special ceremony at The Peace Palace in The Hague, Netherlands, on 29 June 2000. Queen Beatrix of the Netherlands attended the ceremony. The Charter has since then been formally endorsed by thousands of organizations representing millions of people, including the UNESCO Conference of Member States, the World Conservation Union of IUCN, national government ministries, national and international associations of universities, and hundreds of cities and towns in dozens of countries. It has also been endorsed by tens of thousands of individuals, and publicly supported by numerous heads of state.
Preamble to the Earth Charter
“ We stand at a critical moment in Earth's history, a time when humanity must choose its future. As the world becomes increasingly interdependent and fragile, the future at once holds great peril and great promise. To move forward we must recognize that in the midst of a magnificent diversity of cultures and life forms we are one human family and one Earth community with a common destiny. We must join together to bring forth a sustainable global society founded on respect for nature, universal human rights, economic justice, and a culture of peace. Towards this end, it is imperative that we, the peoples of Earth, declare our responsibility to one another, to the greater community of life, and to future generations. ”
General Principles
The Earth Charter urges environmental responsibility, peaceful coexistence, respect for life, democracy, and justice. It is organized into 16 general headings, each covering a general principle, as follows:
1. Respect Earth and life in all its diversity.
2. Care for the community of life with understanding, compassion and love.
3. Build democratic societies that are just, participatory, sustainable and peaceful.
4. Secure Earth's bounty and beauty for present and future generations.
5. Protect and restore the integrity of Earth's ecological systems, with special concern for biological diversity and the natural processes that sustain life.
6. Prevent harm as the best method of environmental protection and, when knowledge is limited, apply a precautionary approach.
7. Adopt patterns of production, consumption and reproduction that safeguard Earth's regenerative capacities, human rights and community well-being.
8. Advance the study of ecological sustainability and promote the open exchange and wide application of the knowledge acquired.
9. Eradicate poverty as an ethical, social and environmental imperative.
10. Ensure that economic activities and institutions at all levels promote human development in an equitable and sustainable manner.
11. Affirm gender equality and equity as prerequisites to sustainable development and ensure universal access to education, health care and economic opportunity.
12. Uphold the right of all, without discrimination, to a natural and social environment supportive of human dignity, bodily health and spiritual well-being, with special attention to the rights of indigenous peoples and minorities.
13. Strengthen democratic institutions at all levels, and provide transparency and accountability in governance, inclusive participation in decision-making, and access to justice.
14. Integrate into formal education and lifelong learning the knowledge, values and skills needed for a sustainable way of life.
15. Treat all living beings with respect and consideration.
16. Promote a culture of tolerance, nonviolence and peace.
Reaction
The Earth Charter has been publicly endorsed, recognized, or supported by people and organizations across a wide range of the political spectrum, from conservative to liberal, as well as from all major religious traditions. has received support from business corporations, grassroots activists, universities, governments, and global non-governmental organizations. Overall, reaction to the document can be characterized as overwhelmingly positive.
However, the Charter has also received opposition from many groups and governments. For example, in the United States and other countries, members of religious groups, such as the Religious Right have objected to the document on the grounds that it is secular, and espouses socialism. Some groups go so far as to complain that it contains no reference to the doctrines of Judeo-Christianity.[citation needed] In addition, some conservatives cite an informal comment by Mikhail Gorbachev that the document is "a kind of Ten Commandments", and point to the fact that at the 2002 World Summit on Sustainable Development in Johannesburg, South Africa, a copy of the document was placed symbolically in an "Ark of Hope" -- an independent project by the American artist Sally Linder. Some members of the American Religious Right infer from these incidents that the Charter is a proposed replacement for the Ten Commandments, and part of a conspiracy to establish a New World Government that replaces National Sovereignty.
Earth Charter International, the organization responsible for promoting the Charter, argues in its literature that the Earth Charter is respectful and inclusive of all religious traditions. They state that the Charter itself makes no statements to support these claims of intent to supplant any of the world's religions or to create a world government. In their opinion, the Charter is simply a statement of common ethical values that recognises humanity's shared responsibility to the Earth and to each other. It is similar, in this respect, to the work of Jacques Maritain, who discovered that all human beings could agree on basic values, regardless of the many disparate beliefs that backed them.
Some Libertarians also express numerous critiques of the Charter, including a concern that the Charter's language calling for 'economic justice' is equivalent to espousing socialism. But the Charter's leadership has stated that it does not adhere to any specific political ideology, and support for the Earth Charter has come from both traditionally "left" and "right"-leaning political leaders, in many countries.
Earth Charter Youth Initiative
The Earth Charter Youth Initiative (ECYI) (http://www.earthcharterinaction.org/youth/) is a network of young activists, youth NGOs, and partners who share a common interest in sustainable development and the Earth Charter.
Dingo Fence
The Dingo Fence or Dog Fence is a pest-exclusion fence that was built in Australia during the 1880s and finished in 1885, to keep dingoes out of the relatively fertile south-east part of the continent (where they had largely been exterminated) and protect the sheep flocks of southern Queensland. It is one of the longest structures on the planet, and the world's longest fence. It would eventually stretch 5,320 km (3,306 mi) from Jimbour on the Darling Downs near Dalby through thousands of miles of arid country to the Eyre peninsula on the Great Australian Bight. It was only partly successful; Dingoes can still be found in parts of the southern states to this day, and although the fence helped reduce losses of sheep to predators, this was counterbalanced by increased pasture competition from rabbits and kangaroos.
Geography
The 2,500 km (1,553 mi) section of the fence in Queensland is also known as the Barrier Fence or Wild Dog Barrier Fence. It is administered by the Department of Natural Resources and Water. The Wild Dog Barrier Fence staff has 23 employees, with two person teams which patrol a 300 km (186 mi) section of the fence once every week. There are depots at Quilpie and Roma.
It joins the Border Fence in New South Wales, where it stretches for 584 km (363 mi) along Latitude 29. The fence passes the point where the three states of Queensland, New South Wales and South Australia meet (Cameron's corner), where there is a brass plate on the survey monument. It is known as the Dog Fence in South Australia, which is 2,225 km (1,383 mi) long.
Physical design
The fence is 180 cm (5.9 ft) high made of wire mesh, and extends for 30 cm (1.0 ft) underground. The fence line on both sides is cleared to a 5 m (5.5 yd) width. Star pickets are spaced every 9 m (9.8 yd). At first it was unsuccessfully used to try and keep out rabbits, with the fence built originally as a rabbit proof fence in 1884. It was more successful at keeping out pigs, kangaroos, emus and brumbies. In 1914 it was converted into a dog-proof fence.
Parts of the Dingo Fence are lit at night by 86 mm (3.4 in) cold cathode fluorescent lamps which are alternately red and white. They are powered by long life batteries which are charged by photovoltaic cells during the day.
The fence is held together by Gripples.
Environmental impact
It seems that there are fewer kangaroos and emus on the north western side of the fence where the dingoes are, suggesting that the dingoes' presence has an impact on the populations of those. It has also been suggested that the larger kangaroo populations inside the fence have been caused by the lack of dingo predation, and competition for food leads to lower sheep stocking rates than would be possible without the fence.
Journalist James Woodford travelled along the fence and wrote an account of his trip called "The Dog Fence."
Geography
The 2,500 km (1,553 mi) section of the fence in Queensland is also known as the Barrier Fence or Wild Dog Barrier Fence. It is administered by the Department of Natural Resources and Water. The Wild Dog Barrier Fence staff has 23 employees, with two person teams which patrol a 300 km (186 mi) section of the fence once every week. There are depots at Quilpie and Roma.
It joins the Border Fence in New South Wales, where it stretches for 584 km (363 mi) along Latitude 29. The fence passes the point where the three states of Queensland, New South Wales and South Australia meet (Cameron's corner), where there is a brass plate on the survey monument. It is known as the Dog Fence in South Australia, which is 2,225 km (1,383 mi) long.
Physical design
The fence is 180 cm (5.9 ft) high made of wire mesh, and extends for 30 cm (1.0 ft) underground. The fence line on both sides is cleared to a 5 m (5.5 yd) width. Star pickets are spaced every 9 m (9.8 yd). At first it was unsuccessfully used to try and keep out rabbits, with the fence built originally as a rabbit proof fence in 1884. It was more successful at keeping out pigs, kangaroos, emus and brumbies. In 1914 it was converted into a dog-proof fence.
Parts of the Dingo Fence are lit at night by 86 mm (3.4 in) cold cathode fluorescent lamps which are alternately red and white. They are powered by long life batteries which are charged by photovoltaic cells during the day.
The fence is held together by Gripples.
Environmental impact
It seems that there are fewer kangaroos and emus on the north western side of the fence where the dingoes are, suggesting that the dingoes' presence has an impact on the populations of those. It has also been suggested that the larger kangaroo populations inside the fence have been caused by the lack of dingo predation, and competition for food leads to lower sheep stocking rates than would be possible without the fence.
Journalist James Woodford travelled along the fence and wrote an account of his trip called "The Dog Fence."
Dioxin
Not to be confused with dioxane or digoxin.
Dioxin is a heterocyclic, organic, antiaromatic compound with the chemical formula C4H4O2. There are two isomers, 1,2-dioxin (or o-dioxin) and 1,4-dioxin (or p-dioxin). Their chemical structures are shown at right. The ortho isomer 1,2-dioxin is very unstable due to its peroxide-like characteristics. The known properties of 1,4-dioxin are listed in the infobox to the right.
1,4-dioxin can be prepared by cycloaddition, namely by the Diels-Alder reaction.
Dioxin is used as a blanket term for a family of chemical compounds that are formed through combustion, chlorine bleaching and manufacturing processes. The combination of heat and chlorine creates dioxin. Since chlorine is often a part of the earth's environment, natural ecological activity such as volcanic activity and forest fires can lead to the formation of dioxin.Nevertheless, dioxin, a highly carcinogenic and toxic compound, is mostly created by human activity.
Other meanings
Skeletal formulas and substituent numbering schemes of Dioxin isomers
The skeletal formula and substituent numbering scheme of dibenzo-1,4-dioxin, the parent compound of PCDDs
The word dioxin can also in a general way refer to compounds whose molecules have a dioxin core skeletal structure with substituent molecular groups attached to it. For example, dibenzo-1,4-dioxin is a compound whose structure consists of two benzo- groups fused onto a 1,4-dioxin ring as shown below (see also Dibenzodioxin).
Because of their extreme importance as environmental pollutants, current scientific literature uses the name dioxins commonly for simplification to denote the chlorinated derivatives of dibenzo-1,4-dioxin, more precisely the polychlorinated dibenzodioxins (PCDDs), among which TCDD, a tetrachlorinated derivative, is the best known. The polychlorinated dibenzodioxins, which can also be classified in the family of halogenated organic compounds, have been shown to bioaccumulate in humans and wildlife due to their lipophilic properties, and are known teratogens, mutagens, and carcinogens. References under the main article on polychlorinated dibenzodioxins.
Additionally, sometimes with dioxins a similar, but unrelated compound type the polychlorinated dibenzofurans of like importance are also implied.
Toxicity
Some dioxin derivatives are carcinogenic, and directly correllated with an increase in the likelihood of developing cancer (see above). Scientists are working to establish their exact toxicity. The job is made difficult because dioxins are not a single compound, but a mixture. Toxicity depends on the particular molecular arrangement of the compound. The compound of highest known toxicity is 2,3,7,8-tetrachlorodibenzo-1,4-dioxin (pictured here as well).
Polychlorinated dibenzodioxins
The word dioxins sometimes refers to polychlorinated dibenzodioxins (PCDDs), a class of chlorinated dioxin derivatives. PCDD exposures are suspected in famous cases including Vietnam War veteran illnesses, the Seveso disaster, and the poisoning of Viktor Yushchenko.
Body response
Small amounts of dioxin at the scale of picograms, particularly dibenzo-dioxins, induces CYP 1A1 strongly. Dioxin does so by binding to cytosolic Aryl Hydrocarbon Receptor (AhR). The AhR is then translocated to the nucleus where it binds to the Xenobiotic Response Element (XRE) and promotes the transcription of the CYP 1A1 gene.
Dioxin is a heterocyclic, organic, antiaromatic compound with the chemical formula C4H4O2. There are two isomers, 1,2-dioxin (or o-dioxin) and 1,4-dioxin (or p-dioxin). Their chemical structures are shown at right. The ortho isomer 1,2-dioxin is very unstable due to its peroxide-like characteristics. The known properties of 1,4-dioxin are listed in the infobox to the right.
1,4-dioxin can be prepared by cycloaddition, namely by the Diels-Alder reaction.
Dioxin is used as a blanket term for a family of chemical compounds that are formed through combustion, chlorine bleaching and manufacturing processes. The combination of heat and chlorine creates dioxin. Since chlorine is often a part of the earth's environment, natural ecological activity such as volcanic activity and forest fires can lead to the formation of dioxin.Nevertheless, dioxin, a highly carcinogenic and toxic compound, is mostly created by human activity.
Other meanings
Skeletal formulas and substituent numbering schemes of Dioxin isomers
The skeletal formula and substituent numbering scheme of dibenzo-1,4-dioxin, the parent compound of PCDDs
The word dioxin can also in a general way refer to compounds whose molecules have a dioxin core skeletal structure with substituent molecular groups attached to it. For example, dibenzo-1,4-dioxin is a compound whose structure consists of two benzo- groups fused onto a 1,4-dioxin ring as shown below (see also Dibenzodioxin).
Because of their extreme importance as environmental pollutants, current scientific literature uses the name dioxins commonly for simplification to denote the chlorinated derivatives of dibenzo-1,4-dioxin, more precisely the polychlorinated dibenzodioxins (PCDDs), among which TCDD, a tetrachlorinated derivative, is the best known. The polychlorinated dibenzodioxins, which can also be classified in the family of halogenated organic compounds, have been shown to bioaccumulate in humans and wildlife due to their lipophilic properties, and are known teratogens, mutagens, and carcinogens. References under the main article on polychlorinated dibenzodioxins.
Additionally, sometimes with dioxins a similar, but unrelated compound type the polychlorinated dibenzofurans of like importance are also implied.
Toxicity
Some dioxin derivatives are carcinogenic, and directly correllated with an increase in the likelihood of developing cancer (see above). Scientists are working to establish their exact toxicity. The job is made difficult because dioxins are not a single compound, but a mixture. Toxicity depends on the particular molecular arrangement of the compound. The compound of highest known toxicity is 2,3,7,8-tetrachlorodibenzo-1,4-dioxin (pictured here as well).
Polychlorinated dibenzodioxins
The word dioxins sometimes refers to polychlorinated dibenzodioxins (PCDDs), a class of chlorinated dioxin derivatives. PCDD exposures are suspected in famous cases including Vietnam War veteran illnesses, the Seveso disaster, and the poisoning of Viktor Yushchenko.
Body response
Small amounts of dioxin at the scale of picograms, particularly dibenzo-dioxins, induces CYP 1A1 strongly. Dioxin does so by binding to cytosolic Aryl Hydrocarbon Receptor (AhR). The AhR is then translocated to the nucleus where it binds to the Xenobiotic Response Element (XRE) and promotes the transcription of the CYP 1A1 gene.
Ecofascism
Ecofascism, can be used in two different ways:
1. For specific elements of radical environmentalism which are openly affiliated with neo-fascism, or which share conceptual similarities with fascist theories. It is used critically from an external source, and somewhat less commonly used from within as a self label, to refer to various white nationalist and third positionist groups who incorporate environmentalist positions into their ideology.
2. The term is also used as a political epithet by political conservatives to discredit deep ecology, mainstream environmentalism, and other left and non-left ecological positions, and less frequently by political leftists to discredit environmental movements they see as non-left such as deep ecology.
Nazi and Fascist views on ecology
Admiration of nature was a strong theme of the German Nazi party and the Wagnerian German romanticism that predated it, and is also a key issue for some modern fascist movements. The Nazi government also investigated sustainable forestry. The Nazis were at the forefront of conservationism, with Nazi Germany having some of the first legally protected wilderness reserves. During their rise to power, the Nazis were supported by German environmentalists and conservationists, but environmental issues were gradually pushed aside in the build-up to the Second World War.
By contrast, non-German forms of fascism for the most part lacked any noteworthy ecological strand. One exception was the peasant-based Iron Guard of Romania, who saw capitalism, which they associated with Jewry, as being destructive to both the Romanian countryside and their Orthodox Christian culture. Elsewhere in Europe, ecological concerns were found individually rather than collectively, e.g. Julius Evola, an Italian writer and supporter of the Fascist regime of Benito Mussolini, who wrote books romanticizing a primitive state of nature and denouncing "modernism." Some have associated French Esoteric Hitlerist and Hindu convert Savitri Devi with ecofascism, due to her support for animal rights and vegetarianism, which she linked to a condemnation of Jewish dietary practises.
When seeking to understand the environmentalism, vegetarianism, and animal rights policies of Nazi and neo-Nazi groups, one must be aware that these ideas are in no way divorced from these groups' emphasis on Arthur de Gobineau's ideas of biology, eugenics, and social Darwinism. Their concept of racial hygiene was seen as cleansing the human genetic stock, much as ecology cleans the environment. All of these concepts have a common thread, emphasising the importance of nature, and man's duty to behave as steward.
Ecofascism as an attack term
Accusations of ecofascism can come from either the left, as in social ecologist Murray Bookchin's use of the term, or the right, as in Rush Limbaugh and other conservative and Wise Use Movement commentators. In the latter case, it is a hyperbolic use of the term that is applied to all environmentalists, including mainstream groups such as Greenpeace and the Sierra Club.
Accusations of ecofascism are not uncommon, but are usually strenuously denied. For some, cries from mainstream ecologists for regulation of human reproduction and reduction of the world population are suggestive of anti-humanist Nazi policies. However, proponents of population control policies have reacted strongly against these comparisons, regarding them as merely attempts to slander certain sections of the environmental movement (see the article on deep ecology for more details).
In the United Kingdom, the Third Way political party has been accused by left-wing watchdog groups of ecofascism, although Third Way says it has renounced all fascist ideology and describes itself as in the "radical centre". There has been a history of environmentalist views being held by the far-right in the UK, notably by Henry Williamson, Rolf Gardiner, Jorian Jenks and the "Blackshirt Farmer" Bob Saunders. Some have also accused the "radical antiquarian" John Michell of holding ecofascist views. In his 1995 book The Village That Died For England, concerned with the Dorset village of Tyneham which was requisitioned by the British Army, Patrick Wright details much of the history of British ecofascism during the Second World War.
Pentti Linkola can be most accurately described as a kind of totalitarian deep ecologist, and although he does not specifically endorse fascism per se, he has expressed admiration for the German National Socialist regime. He advocates a strong, centralised ecological dictatorship, with harsh population control measures and brutal punishment of those he considers to be environmental abusers. Needless to say, Linkola has attracted considerable controversy both in his home country and worldwide.
The influential European Nouvelle Droite movement, developed by Alain de Benoist and other individuals involved with the GRECE think-tank, have also attracted accusations of ecofascism from the Left, due to their blend of anti-globalism, environmentalism, and European ethno-nationalism. However, De Benoist himself dismisses fascism as "brown Jacobinism", and condemns racial prejudice and populist-nationalists like Jean-Marie le Pen.
Existing ecofascist groups
The actual number of organisations that could properly be described as ecofascist is extremely small. In the United States, the American Nihilist Underground Society promotes its own particular vision of ecofascism.] A related group is the Libertarian National Socialist Green Party, whose emblem is the Nazi swastika on a green background, symbolising the party's synthesis of ecology with National Socialism. The latter has attracted a certain amount of controversy due its connection with high-school killer Jeff Weise, and some have even suggested that it may be a parody.
Quotes
"We recognize that separating humanity from nature, from the whole of life, leads to humankind’s own destruction and to the death of nations. Only through a re-integration of humanity into the whole of nature can our people be made stronger. That is the fundamental point of the biological tasks of our age. Humankind alone is no longer the focus of thought, but rather life as a whole . . . This striving toward connectedness with the totality of life, with nature itself, a nature into which we are born, this is the deepest meaning and the true essence of National Socialist thought."
Ernst Lehmann, Biologischer Wille. Wege und Ziele biologischer Arbeit im neuen Reich, München, 1934
"..."ecofascism" has come to be used mainly as an attack term, with social ecology roots, against the deep ecology movement and its supporters plus, more generally, the environmental movement. Thus, "ecofascist" and "ecofascism", are used not to enlighten but to smear."
David Orton - Ecofascism: What is It? A Left Biocentric Analysis
"I think the growing disregard for the environment, culture and heritage is a natural consequence of capitalism. When people care more about profit than the world they live in that is what happens."
Varg Vikernes
1. For specific elements of radical environmentalism which are openly affiliated with neo-fascism, or which share conceptual similarities with fascist theories. It is used critically from an external source, and somewhat less commonly used from within as a self label, to refer to various white nationalist and third positionist groups who incorporate environmentalist positions into their ideology.
2. The term is also used as a political epithet by political conservatives to discredit deep ecology, mainstream environmentalism, and other left and non-left ecological positions, and less frequently by political leftists to discredit environmental movements they see as non-left such as deep ecology.
Nazi and Fascist views on ecology
Admiration of nature was a strong theme of the German Nazi party and the Wagnerian German romanticism that predated it, and is also a key issue for some modern fascist movements. The Nazi government also investigated sustainable forestry. The Nazis were at the forefront of conservationism, with Nazi Germany having some of the first legally protected wilderness reserves. During their rise to power, the Nazis were supported by German environmentalists and conservationists, but environmental issues were gradually pushed aside in the build-up to the Second World War.
By contrast, non-German forms of fascism for the most part lacked any noteworthy ecological strand. One exception was the peasant-based Iron Guard of Romania, who saw capitalism, which they associated with Jewry, as being destructive to both the Romanian countryside and their Orthodox Christian culture. Elsewhere in Europe, ecological concerns were found individually rather than collectively, e.g. Julius Evola, an Italian writer and supporter of the Fascist regime of Benito Mussolini, who wrote books romanticizing a primitive state of nature and denouncing "modernism." Some have associated French Esoteric Hitlerist and Hindu convert Savitri Devi with ecofascism, due to her support for animal rights and vegetarianism, which she linked to a condemnation of Jewish dietary practises.
When seeking to understand the environmentalism, vegetarianism, and animal rights policies of Nazi and neo-Nazi groups, one must be aware that these ideas are in no way divorced from these groups' emphasis on Arthur de Gobineau's ideas of biology, eugenics, and social Darwinism. Their concept of racial hygiene was seen as cleansing the human genetic stock, much as ecology cleans the environment. All of these concepts have a common thread, emphasising the importance of nature, and man's duty to behave as steward.
Ecofascism as an attack term
Accusations of ecofascism can come from either the left, as in social ecologist Murray Bookchin's use of the term, or the right, as in Rush Limbaugh and other conservative and Wise Use Movement commentators. In the latter case, it is a hyperbolic use of the term that is applied to all environmentalists, including mainstream groups such as Greenpeace and the Sierra Club.
Accusations of ecofascism are not uncommon, but are usually strenuously denied. For some, cries from mainstream ecologists for regulation of human reproduction and reduction of the world population are suggestive of anti-humanist Nazi policies. However, proponents of population control policies have reacted strongly against these comparisons, regarding them as merely attempts to slander certain sections of the environmental movement (see the article on deep ecology for more details).
In the United Kingdom, the Third Way political party has been accused by left-wing watchdog groups of ecofascism, although Third Way says it has renounced all fascist ideology and describes itself as in the "radical centre". There has been a history of environmentalist views being held by the far-right in the UK, notably by Henry Williamson, Rolf Gardiner, Jorian Jenks and the "Blackshirt Farmer" Bob Saunders. Some have also accused the "radical antiquarian" John Michell of holding ecofascist views. In his 1995 book The Village That Died For England, concerned with the Dorset village of Tyneham which was requisitioned by the British Army, Patrick Wright details much of the history of British ecofascism during the Second World War.
Pentti Linkola can be most accurately described as a kind of totalitarian deep ecologist, and although he does not specifically endorse fascism per se, he has expressed admiration for the German National Socialist regime. He advocates a strong, centralised ecological dictatorship, with harsh population control measures and brutal punishment of those he considers to be environmental abusers. Needless to say, Linkola has attracted considerable controversy both in his home country and worldwide.
The influential European Nouvelle Droite movement, developed by Alain de Benoist and other individuals involved with the GRECE think-tank, have also attracted accusations of ecofascism from the Left, due to their blend of anti-globalism, environmentalism, and European ethno-nationalism. However, De Benoist himself dismisses fascism as "brown Jacobinism", and condemns racial prejudice and populist-nationalists like Jean-Marie le Pen.
Existing ecofascist groups
The actual number of organisations that could properly be described as ecofascist is extremely small. In the United States, the American Nihilist Underground Society promotes its own particular vision of ecofascism.] A related group is the Libertarian National Socialist Green Party, whose emblem is the Nazi swastika on a green background, symbolising the party's synthesis of ecology with National Socialism. The latter has attracted a certain amount of controversy due its connection with high-school killer Jeff Weise, and some have even suggested that it may be a parody.
Quotes
"We recognize that separating humanity from nature, from the whole of life, leads to humankind’s own destruction and to the death of nations. Only through a re-integration of humanity into the whole of nature can our people be made stronger. That is the fundamental point of the biological tasks of our age. Humankind alone is no longer the focus of thought, but rather life as a whole . . . This striving toward connectedness with the totality of life, with nature itself, a nature into which we are born, this is the deepest meaning and the true essence of National Socialist thought."
Ernst Lehmann, Biologischer Wille. Wege und Ziele biologischer Arbeit im neuen Reich, München, 1934
"..."ecofascism" has come to be used mainly as an attack term, with social ecology roots, against the deep ecology movement and its supporters plus, more generally, the environmental movement. Thus, "ecofascist" and "ecofascism", are used not to enlighten but to smear."
David Orton - Ecofascism: What is It? A Left Biocentric Analysis
"I think the growing disregard for the environment, culture and heritage is a natural consequence of capitalism. When people care more about profit than the world they live in that is what happens."
Varg Vikernes
Souterrain
Souterrain (from French 'sous terrain', meaning 'under ground') is a name given by archaeologists to a type of underground structure associated mainly with the Atlantic Iron Age. These structures appear to have been brought northwards from Gaul during the late Iron Age. Regional names include earth houses, fogous and Pictish houses. The term souterrain has been used as a distinct term from fogou. In Cornwall the regional name of fogou is applied to souterrain structures. The design of underground structures has been shown to differ among regions; for example, in western Cornwall the design and function of the fogou appears to correlate with a larder use.
Souterrains are often referred to locally in Ireland simply as 'caves'. A.T. Lucas, folklorist and Director of the National Museum of Ireland in the 1960s, published a study of the references to souterrains in the early Irish annals. An article by Warner on the archaeology of souterrains, although published thirty years ago, is still possibly the best general overview of the subject. The most comprehensive study of Irish souterrains is Clinton's 2001 work, containing chapters on distribution, associated settlements, function, finds, chronology and no less than thirteen appendices on various structural aspects of souterrains themselves. The book lacks an index. A short summary account of souterrains in Ireland appeared in the quarterly magazine Archaeology Ireland in 2004.
The name comes from the French language, in which it means "underground passageway". In languages other than English, it is sometimes used to mean 'basement', especially in warehouses.
Souterrains are underground galleries and, in their early stages, were always associated with a settlement. The galleries were dug out and then lined with stone slabs or wood before being reburied. In cases where they were cut into rock this was not always necessary. They do not appear to have been used for burial or ritual purposes and it has been suggested that they were food stores or hiding places during times of strife, although some of them would have had very obvious entrances. In Ireland they are often found inside or in close proximity to a ringfort and as such are thought to be mainly contemporary with them, making them somewhat later in date than in other countries. This date is reinforced by many examples where ogham stones, dating to around the sixth century have been reused as roofing lintels or door posts, most notably at the widened natural limestone fissure at the 'cave of the cats' in Rathcrogan. Their distribution is very uneven in Ireland with the most notable concentration centred around County Louth. In Scotland some of them may be connected with the same people who built brochs.
Examples
An example of an excavated souterrain is the site at Rosal, Strathnaver, Sutherland. In this excavation, no artefacts or other finds were made inside the structure and the roof may have been only partially covered with stones, a timber roof being present on part of it. It was suggested that the souterrain could have been used as a byre or barn and it was associated with an abandoned settlement.
An example of a partially explored souterrain in northern Scotland, on Shapinsay in the Orkney Islands is Castle Bloody, situated near the seacoast.
A well illustrated account of a souterrain excavated at Newtownbalregan, County Louth, one of the many souterrains discovered during the recent road-building programme in Ireland may be found in Archaeology Ireland Winter 2003 issue.
A full report on the excavation of a three-level souterrain at Farrandreg, Co. Louth, in 1998 gives references for the fourteen souterrains previously excavated in this souterrain-rich county. Finds included a rotary quern, a bone comb, a copper-alloy stick pin, three bone needles and the greater part of a tub-shaped pottery vessel in 'Souterrain ware'. The excavator concluded, on the evidence of the finds, that the souterrain had been closed up in the twelfth century.
Souterrains are often referred to locally in Ireland simply as 'caves'. A.T. Lucas, folklorist and Director of the National Museum of Ireland in the 1960s, published a study of the references to souterrains in the early Irish annals. An article by Warner on the archaeology of souterrains, although published thirty years ago, is still possibly the best general overview of the subject. The most comprehensive study of Irish souterrains is Clinton's 2001 work, containing chapters on distribution, associated settlements, function, finds, chronology and no less than thirteen appendices on various structural aspects of souterrains themselves. The book lacks an index. A short summary account of souterrains in Ireland appeared in the quarterly magazine Archaeology Ireland in 2004.
The name comes from the French language, in which it means "underground passageway". In languages other than English, it is sometimes used to mean 'basement', especially in warehouses.
Souterrains are underground galleries and, in their early stages, were always associated with a settlement. The galleries were dug out and then lined with stone slabs or wood before being reburied. In cases where they were cut into rock this was not always necessary. They do not appear to have been used for burial or ritual purposes and it has been suggested that they were food stores or hiding places during times of strife, although some of them would have had very obvious entrances. In Ireland they are often found inside or in close proximity to a ringfort and as such are thought to be mainly contemporary with them, making them somewhat later in date than in other countries. This date is reinforced by many examples where ogham stones, dating to around the sixth century have been reused as roofing lintels or door posts, most notably at the widened natural limestone fissure at the 'cave of the cats' in Rathcrogan. Their distribution is very uneven in Ireland with the most notable concentration centred around County Louth. In Scotland some of them may be connected with the same people who built brochs.
Examples
An example of an excavated souterrain is the site at Rosal, Strathnaver, Sutherland. In this excavation, no artefacts or other finds were made inside the structure and the roof may have been only partially covered with stones, a timber roof being present on part of it. It was suggested that the souterrain could have been used as a byre or barn and it was associated with an abandoned settlement.
An example of a partially explored souterrain in northern Scotland, on Shapinsay in the Orkney Islands is Castle Bloody, situated near the seacoast.
A well illustrated account of a souterrain excavated at Newtownbalregan, County Louth, one of the many souterrains discovered during the recent road-building programme in Ireland may be found in Archaeology Ireland Winter 2003 issue.
A full report on the excavation of a three-level souterrain at Farrandreg, Co. Louth, in 1998 gives references for the fourteen souterrains previously excavated in this souterrain-rich county. Finds included a rotary quern, a bone comb, a copper-alloy stick pin, three bone needles and the greater part of a tub-shaped pottery vessel in 'Souterrain ware'. The excavator concluded, on the evidence of the finds, that the souterrain had been closed up in the twelfth century.
Earthweek
Earthweek - A Diary of the Planet is a syndicated newspaper column created by Steve Newman. It is published weekly on various days by subscribing newspapers, and reports on events in Earth's natural history. The feature was the first fully paginated newspaper column to be distributed with placed graphics, thanks to the growing popularity of the Macintosh platform in newspaper graphics departments during the late 1980s.
Due to the slow modem speeds common in 1988, early versions of Earthweek were limited to low-resolution graphics. Subscribing newspapers maintained a library of individual icons and the base map, which were used by the "wire frame" of the Pagemaker document distributed to them each week. Earthweek is now created in QuarkXPress with Adobe Illustrator graphics, and is delivered as a complete, integrated package.
A PDF version of the feature may be downloaded by readers in markets where Earthweek is not published.
Typical Earthweek Content
From man-made occurrences to nature's own news, Earthweek provides a weekly overview of headline events affecting our planet -- cyclones, floods, brushfires, oil spills and climate change. Other stories are a bit more unusual -- monkey attacks, snake infestations and a bounty of phenomena as diverse as nature itself.
Earthweek initial focused mainly on breaking weather news stories, along with a complement of items about volcanic eruptions, El Niño outbreaks and unusual animal stories. That focus has widened in recent years to be more inclusive of global warming issues and how wildlife is reacting to the changing climate.
Distribution of Earthweek
The feature premiered in the San Francisco Chronicle on Saturday, January 2, 1988, and began syndication through the now-defunct Chronicle Features in early September of that year.
Earthweek moved briefly to Universal Press Syndicate in 1998, when Andrews McMeel Universal purchased Chronicle Features. Author Steve Newman moved the column to the Los Angeles Times Syndicate in June 1998, where its circulation increased and an online version was created.
A subsequent purchase of that syndicate by the Tribune Company absorbed Earthweek into Tribune Media Services, which discontinued the online version and oversaw a steady decline in the column's print subscriptions and sales.
Earthweek rejoined Universal Press Syndicate in June 2003, and is now published by nearly 100 newspapers worldwide. An interactive version was launched by UClick in July 2006.
Helping Students Monitor a Dynamic Planet
Many educators use the feature in a weekly assignment to elementary and middle school students. By encouraging a close examination of Earthweek's map and summaries, students can increase their understanding of both geography and the environment. Educator Lori Agan wrote an essay in the National Science Teachers Association journal Science Scope that documents how her use of Earthweek has benefited her students.
Due to the slow modem speeds common in 1988, early versions of Earthweek were limited to low-resolution graphics. Subscribing newspapers maintained a library of individual icons and the base map, which were used by the "wire frame" of the Pagemaker document distributed to them each week. Earthweek is now created in QuarkXPress with Adobe Illustrator graphics, and is delivered as a complete, integrated package.
A PDF version of the feature may be downloaded by readers in markets where Earthweek is not published.
Typical Earthweek Content
From man-made occurrences to nature's own news, Earthweek provides a weekly overview of headline events affecting our planet -- cyclones, floods, brushfires, oil spills and climate change. Other stories are a bit more unusual -- monkey attacks, snake infestations and a bounty of phenomena as diverse as nature itself.
Earthweek initial focused mainly on breaking weather news stories, along with a complement of items about volcanic eruptions, El Niño outbreaks and unusual animal stories. That focus has widened in recent years to be more inclusive of global warming issues and how wildlife is reacting to the changing climate.
Distribution of Earthweek
The feature premiered in the San Francisco Chronicle on Saturday, January 2, 1988, and began syndication through the now-defunct Chronicle Features in early September of that year.
Earthweek moved briefly to Universal Press Syndicate in 1998, when Andrews McMeel Universal purchased Chronicle Features. Author Steve Newman moved the column to the Los Angeles Times Syndicate in June 1998, where its circulation increased and an online version was created.
A subsequent purchase of that syndicate by the Tribune Company absorbed Earthweek into Tribune Media Services, which discontinued the online version and oversaw a steady decline in the column's print subscriptions and sales.
Earthweek rejoined Universal Press Syndicate in June 2003, and is now published by nearly 100 newspapers worldwide. An interactive version was launched by UClick in July 2006.
Helping Students Monitor a Dynamic Planet
Many educators use the feature in a weekly assignment to elementary and middle school students. By encouraging a close examination of Earthweek's map and summaries, students can increase their understanding of both geography and the environment. Educator Lori Agan wrote an essay in the National Science Teachers Association journal Science Scope that documents how her use of Earthweek has benefited her students.
Earth house
An earth house is an architectural style characterized by the use of natural terrain to help form the walls of a house. An earth house is usually set partially into the ground and covered with thin growth, and is often intended to have a small ecological footprint. Modern earth houses are built with concrete walls and insulation.
Introduction
Unlike traditional residential houses built on the ground, the aim of building an earth house is not to live under or in the ground, but with it. If ground and house are separated, a house is built “into the air”, resulting in the loss of heat and humidity, and the exterior shell of a building loses lifespan. The earth house concept uses the ground as an insulating blanket that efficiently protects it from rain, low temperatures, wind and natural abrasion. An earth house does not have to be built under the ground, it can be placed onto naturally grown terrain. The earth house is a flexible construction which can be built according to the wishes of its owners, fulfilling the requirements for individuality, environmentally friendly construction, and energy conservation. The structural engineering of an earth house creates for an organic design requiring spatial sense and creativity. Earth house architecture brings to mind habitable sculptures, incorporating artistic claim and sculptural quality.
Grain Earth House.
The entrance to an earth house can be in the roof. Early earth houses had no windows, but modern earth houses can have windows inside the roof which can mean that more natural sunlight enters them than in an average house. The earth house does not have to be simple in design or low in cost; "The Burrow" in Canterbury, UK, went on sale for £2 million in May 2007. It featured five bedrooms and was designed by Patrick Kennedy-Sanigar, who is now trying to build a "village" using this type of housing.
Structural engineering
Structures, which are designed as integral arches, can be constructed as stiff individual objects or by means of a sprayed concrete procedure. Arches made of sprayed concrete provide for free and organic shapes, allowing rooms to become suffused with light. The sprayed concrete procedure was first used by natural scientist Carl Akeley in 1911. Akeley patented a device able to spray fine-grained concrete. While sprayed concrete is mainly applied in underground engineering and tunnel construction, Friedrich Kiesler was the first to use this technique for the construction of buildings. Swiss architect Peter Vetsch improved the technique over several years. To date, he has built over 40 earth houses using sprayed concrete, and he can therefore be considered the leading authority in this area of expertise.The sprayed concrete is applied to a finely meshed metal stretch net which is welded onto the supporting armature. The curvatures are bent and formed according to the intended shape of the building. A 20 cm thick polyurethane solid-foam-insulation is sprayed onto the outside of the arches, protecting the house from low or high temperatures. A fleece filter mat is then laid on top of this and the building is covered with a thick layer of soil some 80 cm to 3 metres thick. The foundation of the buildings designed by Peter Vetsch are built conventionally. The interior walls of an earth house are furnished using loam rendering which provides superior humidity compensation. The loam rendering is finally coated with lime-white cement paint.
Design and architecture
Earth houses by exponents like Peter Vetsch or Arthur Quarmby are based on the interpretation of an environmentally conscious, ecological and progressive architecture. They stand out due to their closeness to nature and allow an experience beyond the usual four walls and their right angles. The earth house concept uses its surroundings as an advantage – the surroundings are not adapted to the building, the house is shaped in order to preserve the natural environment. Modern earth-house architecture incorporates the latest interior finishing, such as contemporary kitchens, bathrooms and house-control systems. Furthermore, every house is newly designed in accordance with the wishes of its owners. Every earth house can therefore be considered a highly individual object. The focus of this planning process is the human being, who is given the opportunity to integrate a “third skin” into his own architectural language. Earth houses can be built as single residential houses or housing estates.
Advantages
The advantages of an earth house are primarily ecological and security-related.
Insulation, energy and CO2 savings
One of the main ecological benefits of earth-house architecture lies in its natural insulation. The unique architecture cools the house down in summer and keeps it warm in winter. A further advantage is the higher air humidity of 50 to 70% compared to overheated rooms of conventional houses in winter. Furthermore, as earth houses are impermeable, they can be considered ideal for controlled air conditioning.
Windstorm and earthquake protection
The unique architecture of earth houses protects them against severe windstorms. They cannot be torn away or tipped over by strong winds. Structural engineering and, above all, the lack of corners and exposed parts (roof), eliminate vulnerable surfaces which would otherwise suffer from storm damage. Furthermore, earth houses benefit from improved stability due to the organic shapes of arches.
Landscape protection and land use
Compared to conventional buildings, earth houses fit perfectly into their surroundings. Their soil-covered roofs incorporate the environment and protect the natural scenery. Soil-covered roofs return parts of the green landscape and, therefore, contribute to the oxygen-nitrogen balance. Contrary to conventional roofs, earth-house roofs bring back usable surface. They can also be built as terraced structures if the slope is appropriate, thus using far less land area, because the structure can be built right up to the property boundary. Owing to the condensed means of construction, more green space remains available. Furthermore, earth-house structures can easily be built into hilly terrain, compared to conventional houses, which require flat land.
Fire protection
Compared to other building materials, such as wood, earth houses feature efficient fire protection owing both to the use of concrete and the properties of the earth itself.
Roof planting
Roof covering is done using excavation material which allows for planting useful plants. As the roof collects and ties up most of the rain water, rivers are relieved of sudden and huge amounts of water.
Light
Earth houses are built using wide glass facades and dome-lights, allowing rooms to become bright and suffused with light. Dome-lights provide natural light for bathrooms and secondary rooms.
Disadvantages
The specific architecture of earth houses usually leads to non-righted, round-shaped walls, which can cause problems concerning the interior decoration, especially regarding furniture and large paintings. However, these problems can be anticipated during the conceptual design of an earth house.
Introduction
Unlike traditional residential houses built on the ground, the aim of building an earth house is not to live under or in the ground, but with it. If ground and house are separated, a house is built “into the air”, resulting in the loss of heat and humidity, and the exterior shell of a building loses lifespan. The earth house concept uses the ground as an insulating blanket that efficiently protects it from rain, low temperatures, wind and natural abrasion. An earth house does not have to be built under the ground, it can be placed onto naturally grown terrain. The earth house is a flexible construction which can be built according to the wishes of its owners, fulfilling the requirements for individuality, environmentally friendly construction, and energy conservation. The structural engineering of an earth house creates for an organic design requiring spatial sense and creativity. Earth house architecture brings to mind habitable sculptures, incorporating artistic claim and sculptural quality.
Grain Earth House.
The entrance to an earth house can be in the roof. Early earth houses had no windows, but modern earth houses can have windows inside the roof which can mean that more natural sunlight enters them than in an average house. The earth house does not have to be simple in design or low in cost; "The Burrow" in Canterbury, UK, went on sale for £2 million in May 2007. It featured five bedrooms and was designed by Patrick Kennedy-Sanigar, who is now trying to build a "village" using this type of housing.
Structural engineering
Structures, which are designed as integral arches, can be constructed as stiff individual objects or by means of a sprayed concrete procedure. Arches made of sprayed concrete provide for free and organic shapes, allowing rooms to become suffused with light. The sprayed concrete procedure was first used by natural scientist Carl Akeley in 1911. Akeley patented a device able to spray fine-grained concrete. While sprayed concrete is mainly applied in underground engineering and tunnel construction, Friedrich Kiesler was the first to use this technique for the construction of buildings. Swiss architect Peter Vetsch improved the technique over several years. To date, he has built over 40 earth houses using sprayed concrete, and he can therefore be considered the leading authority in this area of expertise.The sprayed concrete is applied to a finely meshed metal stretch net which is welded onto the supporting armature. The curvatures are bent and formed according to the intended shape of the building. A 20 cm thick polyurethane solid-foam-insulation is sprayed onto the outside of the arches, protecting the house from low or high temperatures. A fleece filter mat is then laid on top of this and the building is covered with a thick layer of soil some 80 cm to 3 metres thick. The foundation of the buildings designed by Peter Vetsch are built conventionally. The interior walls of an earth house are furnished using loam rendering which provides superior humidity compensation. The loam rendering is finally coated with lime-white cement paint.
Design and architecture
Earth houses by exponents like Peter Vetsch or Arthur Quarmby are based on the interpretation of an environmentally conscious, ecological and progressive architecture. They stand out due to their closeness to nature and allow an experience beyond the usual four walls and their right angles. The earth house concept uses its surroundings as an advantage – the surroundings are not adapted to the building, the house is shaped in order to preserve the natural environment. Modern earth-house architecture incorporates the latest interior finishing, such as contemporary kitchens, bathrooms and house-control systems. Furthermore, every house is newly designed in accordance with the wishes of its owners. Every earth house can therefore be considered a highly individual object. The focus of this planning process is the human being, who is given the opportunity to integrate a “third skin” into his own architectural language. Earth houses can be built as single residential houses or housing estates.
Advantages
The advantages of an earth house are primarily ecological and security-related.
Insulation, energy and CO2 savings
One of the main ecological benefits of earth-house architecture lies in its natural insulation. The unique architecture cools the house down in summer and keeps it warm in winter. A further advantage is the higher air humidity of 50 to 70% compared to overheated rooms of conventional houses in winter. Furthermore, as earth houses are impermeable, they can be considered ideal for controlled air conditioning.
Windstorm and earthquake protection
The unique architecture of earth houses protects them against severe windstorms. They cannot be torn away or tipped over by strong winds. Structural engineering and, above all, the lack of corners and exposed parts (roof), eliminate vulnerable surfaces which would otherwise suffer from storm damage. Furthermore, earth houses benefit from improved stability due to the organic shapes of arches.
Landscape protection and land use
Compared to conventional buildings, earth houses fit perfectly into their surroundings. Their soil-covered roofs incorporate the environment and protect the natural scenery. Soil-covered roofs return parts of the green landscape and, therefore, contribute to the oxygen-nitrogen balance. Contrary to conventional roofs, earth-house roofs bring back usable surface. They can also be built as terraced structures if the slope is appropriate, thus using far less land area, because the structure can be built right up to the property boundary. Owing to the condensed means of construction, more green space remains available. Furthermore, earth-house structures can easily be built into hilly terrain, compared to conventional houses, which require flat land.
Fire protection
Compared to other building materials, such as wood, earth houses feature efficient fire protection owing both to the use of concrete and the properties of the earth itself.
Roof planting
Roof covering is done using excavation material which allows for planting useful plants. As the roof collects and ties up most of the rain water, rivers are relieved of sudden and huge amounts of water.
Light
Earth houses are built using wide glass facades and dome-lights, allowing rooms to become bright and suffused with light. Dome-lights provide natural light for bathrooms and secondary rooms.
Disadvantages
The specific architecture of earth houses usually leads to non-righted, round-shaped walls, which can cause problems concerning the interior decoration, especially regarding furniture and large paintings. However, these problems can be anticipated during the conceptual design of an earth house.
Delayed nuclear radiation
Delayed nuclear radiation can occur in a nuclear decay. It happens when an isotope decays into a very short-lived isotope and then decays again to a relatively long-lived isotope. The short-lived isotope is usually a meta-stable nuclear isomer.
For example, Gallium-73 decays via beta decay into Germanium-73m which is very short-lived. The Germanium isotope emits two weak gamma rays and a conversion electron.
7331Ga → 73m32Ge + 2γ → 7332Ge+ + 2γ + e−
Because the middle isotope is so short-lived, the gamma rays are considered part of the Gallium decay. Therefore the above equation is simplified.
7331Ga → 7332Ge+ + 4γ + e−
However, since there is a short time delay between the beta decay and the high energy gamma emissions and the third and fourth gamma rays, it is said that the lower energy gamma rays are delayed.
Delayed gamma emissions are the most common form of delayed radiation but it is not the only form. It is common for the short-lived isotopes to have delayed emissions of various particles. In these cases it is commonly called a beta-delayed emission. This is because the decay is delayed until a beta decay takes place. For instance nitrogen-17 emits two beta-delayed neutrons after its primary beta emission. Just as in the above delayed gamma emission, the nitrogen is not the actual source of the neutrons, a short lived isotope of oxygen is.
For example, Gallium-73 decays via beta decay into Germanium-73m which is very short-lived. The Germanium isotope emits two weak gamma rays and a conversion electron.
7331Ga → 73m32Ge + 2γ → 7332Ge+ + 2γ + e−
Because the middle isotope is so short-lived, the gamma rays are considered part of the Gallium decay. Therefore the above equation is simplified.
7331Ga → 7332Ge+ + 4γ + e−
However, since there is a short time delay between the beta decay and the high energy gamma emissions and the third and fourth gamma rays, it is said that the lower energy gamma rays are delayed.
Delayed gamma emissions are the most common form of delayed radiation but it is not the only form. It is common for the short-lived isotopes to have delayed emissions of various particles. In these cases it is commonly called a beta-delayed emission. This is because the decay is delayed until a beta decay takes place. For instance nitrogen-17 emits two beta-delayed neutrons after its primary beta emission. Just as in the above delayed gamma emission, the nitrogen is not the actual source of the neutrons, a short lived isotope of oxygen is.
Decomposer
Decomposers (or saprotrophs) are organisms that consume dead organisms, and, in doing so, carry out the natural process of decomposition. Like herbivores and predators, decomposers are heterotrophic, meaning that they use organic substrates to get their energy, carbon and nutrients for growth and development. Decomposers use deceased organisms and non-living organic compounds as their food source. The primary decomposers are bacteria and fungi.
Importance of decomposers in the ecosystem
this is so wrong and didn't help me at all!!!!!!When a plant or animal dies, it leaves behind nutrients and energy in the organic material that comprised its body. Scavengers and detritivores can feed on the carcasses, but they will inevitably leave behind a considerable amount of unused energy and nutrients. Unused energy and nutrients will be present both in the unconsumed portions (bones, feathers or fur in the case of animals, wood and other indigestable litter in the case of plants) and in the feces of the scavengers and detritivores. Decomposers eat things by breaking down this remaining organic matter by breaking it into pieces. Decomposers eventually convert all organic matter into carbon dioxide (which they respire) and nutrients. This releases raw nutrients (such as nitrogen, phosphorus, and magnesium) in a a form usable to plants and algae, which incorporate the chemicals into their own cells. This process resupplies nutrients to the ecosystem, in turn allowing for greater primary production.
Although decomposers are generally located on the bottom of ecosystem diagrams such as food chains, food webs, and energy pyramids, decomposers in the biosphere are crucial to the environment. By breaking down dead material, they provide the nutrients that other organisms need to survive. As decomposers feed on dead organisms, they leave behind nutrients. These nutrients then become part of the soil. Therefore, more plants can grow and thrive.
Bacteria
Bacteria are the primary decomposers of dead animals (carrion) and are the primary decomposers of dead plant matter (litter) in some ecosystems. In soils, where decomposition occurs in terrestrial ecosystems, bacteria are capable of rapid growth and reproduction. This allows bacteria to rapidly utilize and decompose available organic matter, especially if the organic matter has relatively simple chemical bonds. Bacteria were traditionally believed to be less abundant in soils than fungi, and therefore less important as decomposers. In some grasslands, however, active bacteria can be more abundant than active fungal hyphae, and bacteria in such ecosystems are much more important in the recycling of nutrients. Bacteria can also be very important in agricultural fields, because tillage usually increases the abundance of bacteria relative to fungi.
Fungi
Fungi are the primary decomposers of litter in many ecosystems. Unlike bacteria, which are unicellular, most saprotrophic fungi grow as a branching network of hyphae. While bacteria are restricted to growing and feeding on the exposed surfaces of organic matter, fungi can use their hyphae to penetrate larger pieces of organic matter. Additionally, only fungi have evolved the enzymes necessary to decompose lignin, a chemically complex substance found in wood. These two factors make fungi the primary decomposers in forests, where litter has high concentrations of lignin and is often in large pieces.Also, If manufunctured with other organismes, may grow elsewhere from its chemical persuit, leaving behind the same type of bacteria left on the plant,tree organism, Etc.
Importance of decomposers in the ecosystem
this is so wrong and didn't help me at all!!!!!!When a plant or animal dies, it leaves behind nutrients and energy in the organic material that comprised its body. Scavengers and detritivores can feed on the carcasses, but they will inevitably leave behind a considerable amount of unused energy and nutrients. Unused energy and nutrients will be present both in the unconsumed portions (bones, feathers or fur in the case of animals, wood and other indigestable litter in the case of plants) and in the feces of the scavengers and detritivores. Decomposers eat things by breaking down this remaining organic matter by breaking it into pieces. Decomposers eventually convert all organic matter into carbon dioxide (which they respire) and nutrients. This releases raw nutrients (such as nitrogen, phosphorus, and magnesium) in a a form usable to plants and algae, which incorporate the chemicals into their own cells. This process resupplies nutrients to the ecosystem, in turn allowing for greater primary production.
Although decomposers are generally located on the bottom of ecosystem diagrams such as food chains, food webs, and energy pyramids, decomposers in the biosphere are crucial to the environment. By breaking down dead material, they provide the nutrients that other organisms need to survive. As decomposers feed on dead organisms, they leave behind nutrients. These nutrients then become part of the soil. Therefore, more plants can grow and thrive.
Bacteria
Bacteria are the primary decomposers of dead animals (carrion) and are the primary decomposers of dead plant matter (litter) in some ecosystems. In soils, where decomposition occurs in terrestrial ecosystems, bacteria are capable of rapid growth and reproduction. This allows bacteria to rapidly utilize and decompose available organic matter, especially if the organic matter has relatively simple chemical bonds. Bacteria were traditionally believed to be less abundant in soils than fungi, and therefore less important as decomposers. In some grasslands, however, active bacteria can be more abundant than active fungal hyphae, and bacteria in such ecosystems are much more important in the recycling of nutrients. Bacteria can also be very important in agricultural fields, because tillage usually increases the abundance of bacteria relative to fungi.
Fungi
Fungi are the primary decomposers of litter in many ecosystems. Unlike bacteria, which are unicellular, most saprotrophic fungi grow as a branching network of hyphae. While bacteria are restricted to growing and feeding on the exposed surfaces of organic matter, fungi can use their hyphae to penetrate larger pieces of organic matter. Additionally, only fungi have evolved the enzymes necessary to decompose lignin, a chemically complex substance found in wood. These two factors make fungi the primary decomposers in forests, where litter has high concentrations of lignin and is often in large pieces.Also, If manufunctured with other organismes, may grow elsewhere from its chemical persuit, leaving behind the same type of bacteria left on the plant,tree organism, Etc.
Debt-for-Nature Swap
Debt-for-nature swaps are financial transactions in which a portion of a developing nation's foreign debt is forgiven in exchange for local investments in conservation measures. The concept of debt-for-nature swaps was first conceived by Thomas Lovejoy of the World Wildlife Fund in 1984 as an opportunity to deal with the problems of developing-nation indebtedness and its consequent deleterious effect on the environment. In the wake of the Latin American debt crisis that resulted in steep reductions to the environmental conservation ability of highly-indebted nations, Lovejoy suggested that ameliorating debt and promoting conservation could be done at the same time.
A commercial debt-for-nature swap involves an international non-governmental organization that purchases debt titles from commercial banks on the secondary market. The NGO transfers the debt title to the debtor country, and in exchange the country uses the funds to establish conservation programs. Bilaterial debt-for-nature swaps take place between two governments when one country forgives a portion of the public bilateral debt of a debtor nation in exchange for environmental commitments from that country.
A commercial debt-for-nature swap involves an international non-governmental organization that purchases debt titles from commercial banks on the secondary market. The NGO transfers the debt title to the debtor country, and in exchange the country uses the funds to establish conservation programs. Bilaterial debt-for-nature swaps take place between two governments when one country forgives a portion of the public bilateral debt of a debtor nation in exchange for environmental commitments from that country.
Drip irrigation
Drip irrigation, also known as trickle irrigation or microirrigation is an irrigation method which minimizes the use of water and fertilizer by allowing water to drip slowly to the roots of plants, either onto the soil surface or directly onto the root zone, through a network of valves, pipes, tubing, and emitters.
Modern drip irrigation has arguably become the world's most valued innovation in agriculture since the invention of the impact sprinkler in the 1930s, which replaced flood irrigation. Drip irrigation may also use devices called micro-spray heads, which spray water in a small area, instead of dripping emitters. These are generally used on tree and vine crops with wider root zones. Subsurface drip irrigation (SDI) uses permanently or temporarily buried dripperline or drip tape located at or below the plant roots. It is becoming popular for row crop irrigation, especially in areas where water supplies are limited or recycled water is used for irrigation. Careful study of all the relevant factors like land topography, soil, water, crop and agro-climatic conditions are needed to determine the most suitable drip irrigation system and components to be used in a specific installation.
History
Drip irrigation has been used since ancient times when buried clay pots which were filled with water and the water gradually seeped up into the grass. Modern drip irrigation began its development in Afghanistan in 1866 when researchers began experimenting with irrigation using clay pipe to create combination irrigation and drainage systems. In 1913, E.B. House at Colorado State University succeeded in applying water to the root zone of plants without raising the water table. Perforated pipe was introduced in Germany in the 1920s and in 1934, O.E. Nobey experimented with irrigating through porous canvas hose at Michigan State University.
With the advent of modern plastics during and after World War II, major improvements in drip irrigation became possible. Plastic microtubing and various types of emitters began to be used in the greenhouses of Europe and the United States.
The modern technology of drip irrigation was invented in Israel by Simcha Blass and his son Yeshayahu. Instead of releasing water through tiny holes, blocked easily by tiny particles, water was released through larger and longer passageways by using velocity to slow water inside a plastic emitter. The first experimental system of this type was established in 1959 when Blass partnered with Kibbutz Hatzerim to create an irrigation company called Netafim. Together they developed and patented the first practical surface drip irrigation emitter. This method was very successful and subsequently spread to Australia, North America, and South America by the late 1960s.
In the United States, in the early 1960s, the first drip tape, called Dew Hose, was developed by Richard Chapin of Chapin Watermatics (first system established during 1964). Beginning in 1989, Jain irrigation helped pioneer effective water-management through Drip Irrigation in India. Jain irrigation also introduced some drip irrigation marketing approaches to Indian agriculture such as `Integrated System Approach’, One-Stop-Shop for Farmers, `Infrastructure Status to Drip Irrigation & Farm as Industry.’ The latest developments in the field involve even further reduction in drip rates being delivered and less tendency to clog.
Components and Operation
* Pump or pressurized water source
* Water Filter(s) - Filtration Systems: Sand Separator like Hydro-Cyclone, Screen Filter, Media Filters
* Fertigation Systems (Venturi injector) and Chemigation Equipment (optional)
* Backwash Controller
* Main Line (larger diameter Pipe and Pipe Fittings)
* Hand-operated, electronic, or hydraulic Control Valves and Safety Valves
* Smaller diameter polytube (often referred to as "laterals")
* Poly fittings and Accessories (to make connections)
* Emitting Devices at plants (ex. Emitter or Drippers, micro spray heads, inline drippers, trickle rings)
* Note that in Drip irrigation systems Pump and valves may be manually or automatically operated by a controller.
Most large drip irrigation systems employ some type of filter to prevent clogging of the small emitter flow path by small waterborne particles. New technologies are now being offered that minimize clogging. Some residential systems are installed without additional filters since potable water is already filtered at the water treatment plant. Virtually all drip irrigation equipment manufacturers recommend that filters be employed and generally will not honor warranties unless this is done. Last line filters just before the final delivery pipe are strongly recommended in addition to any other filtration system due to fine particle settlement and accidental insertion of particles in the intermediate lines.
Drip and subsurface drip irrigation is used almost exclusively when using recycled municipal waste water. Regulations typically do not permit spraying water through the air that has not been fully treated to potable water standards.
Because of the way the water is applied in a drip system, traditional surface applications of timed-release fertilizer are sometimes ineffective, so drip systems often mix liquid fertilizer with the irrigation water. This is called fertigation; fertigation and chemigation (application of pesticides and other chemicals to periodically clean out the system, such as chlorine or sulfuric acid) use chemical injector such as diaphragm pumps, piston pumps, or venturi pumps. The chemicals may be added constantly whenever the system is irrigating or at intervals. Fertilizer savings of up to 95% are being reported from recent university field tests using drip fertigation and slow water delivery as compared to timed-release and irrigation by micro spray heads.
If properly designed, installed, and managed, drip irrigation may help achieve water conservation by reducing evaporation and deep drainage when compared to other types of irrigation such as flood or overhead sprinklers since water can be more precisely applied to the plant roots. In addition, drip can eliminate many diseases that are spread through water contact with the foliage. Finally, in regions where water supplies are severely limited, there may be no actual water savings, but rather simply an increase in production while using the same amount of water as before. In very arid regions or on sandy soils, the trick is to apply the irrigation water as slowly as possible.
Pulsed irrigation is sometimes used to decrease the amount of water delivered to the plant at any one time, thus reducing runoff or deep percolation. Pulsed systems are typically expensive and require extensive maintenance. Therefore, the latest efforts by emitter manufacturers are focused toward developing new technologies that deliver irrigation water at ultra-low flow rates, i.e. less than 1.0 liter per hour. Slow and even delivery further improves water use efficiency without incurring the expense and complexity of pulsed delivery equipment.
Garden drip irrigation kits are increasingly popular for the homeowner and consist of a timer, hose and emitter.
Advantage / Disadvantages of Drip Irrigation
The advantages of drip irrigation are:
* Minimized fertilizer/nutrient loss due to localized application and reduced leaching.
* High water application efficiency.
* Leveling of the field not necessary.
* Ability to irrigate irregular shaped fields.
* Allows safe use of recycled water.
* Moisture within the root zone can be maintained at field capacity.
* Soil type plays less important role in frequency of irrigation.
* Minimized soil erosion.
* Highly uniform distribution of water i.e., controlled by output of each nozzle.
* Lower labour cost.
* Variation in supply can be regulated by regulating the valves and drippers.
* Fertigation can easily be included with minimal waste of fertilizers.
* Foliage remains dry thus reducing the risk of disease.
* Usually operated at lower pressure than other types of pressurised irrigation, reducing energy costs.
The disadvantages of drip irrigation are:
* Expense. Initial cost can be more than overhead systems.
* Waste. The sun can affect the tubes used for drip irrigation, shortening their usable life. Longevity is variable.
* Clogging. If the water is not properly filtered and the equipment not properly maintained, it can result in clogging.
* Drip irrigation might be unsatisfactory if herbicides or top dressed fertilizers need sprinkler irrigation for activation.
* Drip tape causes extra cleanup costs after harvest. You'll need to plan for drip tape winding, disposal, recycling or reuse.
* Waste of water, time & harvest, if not installed properly. These systems requires careful study of all the relevant factors like land topography, soil, water, crop and agro-climatic conditions, and suitability of drip irrigation system and its components.
* Germination Problems. In lighter soils subsurface drip may be unable to wet the soil surface for germination. Requires careful consideration of the installation depth.
* Salinity. High application efficiency often results in a failure to meet the leaching requirement, therefore salts build up in the root zone. This is a significant problem in areas where seasonal rainfall is not sufficient to drain salts from the profile.
Modern drip irrigation has arguably become the world's most valued innovation in agriculture since the invention of the impact sprinkler in the 1930s, which replaced flood irrigation. Drip irrigation may also use devices called micro-spray heads, which spray water in a small area, instead of dripping emitters. These are generally used on tree and vine crops with wider root zones. Subsurface drip irrigation (SDI) uses permanently or temporarily buried dripperline or drip tape located at or below the plant roots. It is becoming popular for row crop irrigation, especially in areas where water supplies are limited or recycled water is used for irrigation. Careful study of all the relevant factors like land topography, soil, water, crop and agro-climatic conditions are needed to determine the most suitable drip irrigation system and components to be used in a specific installation.
History
Drip irrigation has been used since ancient times when buried clay pots which were filled with water and the water gradually seeped up into the grass. Modern drip irrigation began its development in Afghanistan in 1866 when researchers began experimenting with irrigation using clay pipe to create combination irrigation and drainage systems. In 1913, E.B. House at Colorado State University succeeded in applying water to the root zone of plants without raising the water table. Perforated pipe was introduced in Germany in the 1920s and in 1934, O.E. Nobey experimented with irrigating through porous canvas hose at Michigan State University.
With the advent of modern plastics during and after World War II, major improvements in drip irrigation became possible. Plastic microtubing and various types of emitters began to be used in the greenhouses of Europe and the United States.
The modern technology of drip irrigation was invented in Israel by Simcha Blass and his son Yeshayahu. Instead of releasing water through tiny holes, blocked easily by tiny particles, water was released through larger and longer passageways by using velocity to slow water inside a plastic emitter. The first experimental system of this type was established in 1959 when Blass partnered with Kibbutz Hatzerim to create an irrigation company called Netafim. Together they developed and patented the first practical surface drip irrigation emitter. This method was very successful and subsequently spread to Australia, North America, and South America by the late 1960s.
In the United States, in the early 1960s, the first drip tape, called Dew Hose, was developed by Richard Chapin of Chapin Watermatics (first system established during 1964). Beginning in 1989, Jain irrigation helped pioneer effective water-management through Drip Irrigation in India. Jain irrigation also introduced some drip irrigation marketing approaches to Indian agriculture such as `Integrated System Approach’, One-Stop-Shop for Farmers, `Infrastructure Status to Drip Irrigation & Farm as Industry.’ The latest developments in the field involve even further reduction in drip rates being delivered and less tendency to clog.
Components and Operation
* Pump or pressurized water source
* Water Filter(s) - Filtration Systems: Sand Separator like Hydro-Cyclone, Screen Filter, Media Filters
* Fertigation Systems (Venturi injector) and Chemigation Equipment (optional)
* Backwash Controller
* Main Line (larger diameter Pipe and Pipe Fittings)
* Hand-operated, electronic, or hydraulic Control Valves and Safety Valves
* Smaller diameter polytube (often referred to as "laterals")
* Poly fittings and Accessories (to make connections)
* Emitting Devices at plants (ex. Emitter or Drippers, micro spray heads, inline drippers, trickle rings)
* Note that in Drip irrigation systems Pump and valves may be manually or automatically operated by a controller.
Most large drip irrigation systems employ some type of filter to prevent clogging of the small emitter flow path by small waterborne particles. New technologies are now being offered that minimize clogging. Some residential systems are installed without additional filters since potable water is already filtered at the water treatment plant. Virtually all drip irrigation equipment manufacturers recommend that filters be employed and generally will not honor warranties unless this is done. Last line filters just before the final delivery pipe are strongly recommended in addition to any other filtration system due to fine particle settlement and accidental insertion of particles in the intermediate lines.
Drip and subsurface drip irrigation is used almost exclusively when using recycled municipal waste water. Regulations typically do not permit spraying water through the air that has not been fully treated to potable water standards.
Because of the way the water is applied in a drip system, traditional surface applications of timed-release fertilizer are sometimes ineffective, so drip systems often mix liquid fertilizer with the irrigation water. This is called fertigation; fertigation and chemigation (application of pesticides and other chemicals to periodically clean out the system, such as chlorine or sulfuric acid) use chemical injector such as diaphragm pumps, piston pumps, or venturi pumps. The chemicals may be added constantly whenever the system is irrigating or at intervals. Fertilizer savings of up to 95% are being reported from recent university field tests using drip fertigation and slow water delivery as compared to timed-release and irrigation by micro spray heads.
If properly designed, installed, and managed, drip irrigation may help achieve water conservation by reducing evaporation and deep drainage when compared to other types of irrigation such as flood or overhead sprinklers since water can be more precisely applied to the plant roots. In addition, drip can eliminate many diseases that are spread through water contact with the foliage. Finally, in regions where water supplies are severely limited, there may be no actual water savings, but rather simply an increase in production while using the same amount of water as before. In very arid regions or on sandy soils, the trick is to apply the irrigation water as slowly as possible.
Pulsed irrigation is sometimes used to decrease the amount of water delivered to the plant at any one time, thus reducing runoff or deep percolation. Pulsed systems are typically expensive and require extensive maintenance. Therefore, the latest efforts by emitter manufacturers are focused toward developing new technologies that deliver irrigation water at ultra-low flow rates, i.e. less than 1.0 liter per hour. Slow and even delivery further improves water use efficiency without incurring the expense and complexity of pulsed delivery equipment.
Garden drip irrigation kits are increasingly popular for the homeowner and consist of a timer, hose and emitter.
Advantage / Disadvantages of Drip Irrigation
The advantages of drip irrigation are:
* Minimized fertilizer/nutrient loss due to localized application and reduced leaching.
* High water application efficiency.
* Leveling of the field not necessary.
* Ability to irrigate irregular shaped fields.
* Allows safe use of recycled water.
* Moisture within the root zone can be maintained at field capacity.
* Soil type plays less important role in frequency of irrigation.
* Minimized soil erosion.
* Highly uniform distribution of water i.e., controlled by output of each nozzle.
* Lower labour cost.
* Variation in supply can be regulated by regulating the valves and drippers.
* Fertigation can easily be included with minimal waste of fertilizers.
* Foliage remains dry thus reducing the risk of disease.
* Usually operated at lower pressure than other types of pressurised irrigation, reducing energy costs.
The disadvantages of drip irrigation are:
* Expense. Initial cost can be more than overhead systems.
* Waste. The sun can affect the tubes used for drip irrigation, shortening their usable life. Longevity is variable.
* Clogging. If the water is not properly filtered and the equipment not properly maintained, it can result in clogging.
* Drip irrigation might be unsatisfactory if herbicides or top dressed fertilizers need sprinkler irrigation for activation.
* Drip tape causes extra cleanup costs after harvest. You'll need to plan for drip tape winding, disposal, recycling or reuse.
* Waste of water, time & harvest, if not installed properly. These systems requires careful study of all the relevant factors like land topography, soil, water, crop and agro-climatic conditions, and suitability of drip irrigation system and its components.
* Germination Problems. In lighter soils subsurface drip may be unable to wet the soil surface for germination. Requires careful consideration of the installation depth.
* Salinity. High application efficiency often results in a failure to meet the leaching requirement, therefore salts build up in the root zone. This is a significant problem in areas where seasonal rainfall is not sufficient to drain salts from the profile.
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