ScienceDaily (23 September 2010) - In recent decades, the rate at which human beings all over the world are pumping ground water from the expanse of water more than doubled, say scientists who have led an unusual, comprehensive assessment of groundwater use.
This rapid contraction of underground storage tanks is essential for daily life and agriculture in many regions, but also to support streams, wetlands, and ecosystems, resisting the land subsidence and saline water in aquifers fresh water. Today, people are drawing so much water from below That They Are adding enough of it to the oceans (Mainly by evaporation, then precipitation) to account for about 25 percent of the annual sea level rise across the planet, the Researchers find. Researchers costattano that today, people are taking so much water under the earth as you are adding across oceans (mainly by evaporation, and precipitation) and mention that this accounts for about 25 percent of the annual level sea \u200b\u200baround the globe.
Soaring global depletion of groundwater is a potential disaster bodes well for an increasingly globalized agriculture, says Marc Bierkens University of Utrecht in Utrecht, the Netherlands, and leader of the new study.
"If you let the population grow by expanding the areas irrigated with groundwater that is recharged, then you will run into a wall at some point in time, and this will cause hunger and social unrest, "warns Bierkens." This is something you can see for miles and miles. "
Soaring global depletion of groundwater is a potential disaster bodes well for an increasingly globalized agriculture, says Marc Bierkens University of Utrecht in Utrecht, the Netherlands, and leader of the new study.
"If you let the population grow by expanding the areas irrigated with groundwater that is recharged, then you will run into a wall at some point in time, and this will cause hunger and social unrest, "warns Bierkens." This is something you can see for miles and miles. "
He and his colleagues published their new findings in an upcoming issue of Geophysical Research Letters, a journal of the American Geophysical Union.
In the new study, which compares estimates of groundwater by rain and additions from other sources and amounts that are removed from agriculture and other uses, the group of researchers created a database of groundwater worldwide, including maps of the regions and the demand for underground water. The researchers also used models to estimate rates which are added to the groundwater aquifers and are withdrawn. For example, to determine rates of groundwater recharge, they simulate a pitched two layers of soil exposed at the top of precipitation, evaporation, and other effects, and uses the course of 44 years (1958 to 2001 ) of the data on precipitation, temperature, evaporation to draw conclusions from the mathematical model.
The application of these techniques in the world in regions ranging from arid areas to those with the humidity of the prairies, the team found that the rate at which groundwater is the world's stock more than doubled between 1960 and 2000, increasing the amount of water lost by 126 to 283 cubic kilometers (30 to 68 cubic miles) of water per year. Since the total amount of groundwater in the world is unknown, it is difficult to say how quickly the world's reserves could disappear in this step. But if the water had been diverted at the same speed from the Great Lakes, they were dry in about 80 years.
Groundwater accounts for approximately 30 percent of available freshwater on the planet, counting the surface waters represent only one percent. The rest of potable water needed for agriculture is locked in polar ice. This means that any reduction in the availability of supply of groundwater may have profound effects for a growing human population.
In the new study, which compares estimates of groundwater by rain and additions from other sources and amounts that are removed from agriculture and other uses, the group of researchers created a database of groundwater worldwide, including maps of the regions and the demand for underground water. The researchers also used models to estimate rates which are added to the groundwater aquifers and are withdrawn. For example, to determine rates of groundwater recharge, they simulate a pitched two layers of soil exposed at the top of precipitation, evaporation, and other effects, and uses the course of 44 years (1958 to 2001 ) of the data on precipitation, temperature, evaporation to draw conclusions from the mathematical model.
The application of these techniques in the world in regions ranging from arid areas to those with the humidity of the prairies, the team found that the rate at which groundwater is the world's stock more than doubled between 1960 and 2000, increasing the amount of water lost by 126 to 283 cubic kilometers (30 to 68 cubic miles) of water per year. Since the total amount of groundwater in the world is unknown, it is difficult to say how quickly the world's reserves could disappear in this step. But if the water had been diverted at the same speed from the Great Lakes, they were dry in about 80 years.
Groundwater accounts for approximately 30 percent of available freshwater on the planet, counting the surface waters represent only one percent. The rest of potable water needed for agriculture is locked in polar ice. This means that any reduction in the availability of supply of groundwater may have profound effects for a growing human population.
The new assessment shows the highest rates of depletion in some of the major agricultural centers of the world, including India, northwest, northeast China, north-eastern Pakistan, in the central valley of California, and the Midwestern United States.
"The rate of depletion has increased almost linearly from 1960 to early 1990," says Bierkens. "But then you see a large increase is linked to the rise of economies and the upcoming issue of the population, mainly in India and China."
Since the level of groundwater is dwindling, the remaining water "will eventually be at a level so low that a farmer managed with its technology can no longer reach, "says Bierkens. He adds that some nations will be able to use expensive technology to obtain fresh water for food production by other means, such as desalination plants or artificial recharge of ground water, but many can not afford it.
Most of the stocks of water extracted from underground ends in the ocean, the researchers note. The research team estimated that the contribution of depletion of ground water at sea level reaches 0.8 mm at ' year, which is about a quarter of the total rate of the increase in sea level by 3.1 millimeters per year. This is about the increase in sea level as well as by melting of glaciers and ice caps outside Greenland and Antarctica, and it exceeds or falls on the high end of previous estimates of the contribution of depletion of ground water at sea level, added the researchers.
"The rate of depletion has increased almost linearly from 1960 to early 1990," says Bierkens. "But then you see a large increase is linked to the rise of economies and the upcoming issue of the population, mainly in India and China."
Since the level of groundwater is dwindling, the remaining water "will eventually be at a level so low that a farmer managed with its technology can no longer reach, "says Bierkens. He adds that some nations will be able to use expensive technology to obtain fresh water for food production by other means, such as desalination plants or artificial recharge of ground water, but many can not afford it.
Most of the stocks of water extracted from underground ends in the ocean, the researchers note. The research team estimated that the contribution of depletion of ground water at sea level reaches 0.8 mm at ' year, which is about a quarter of the total rate of the increase in sea level by 3.1 millimeters per year. This is about the increase in sea level as well as by melting of glaciers and ice caps outside Greenland and Antarctica, and it exceeds or falls on the high end of previous estimates of the contribution of depletion of ground water at sea level, added the researchers.
- An article interssante much, I enjoyed reminding me translate it to my studies and research in groundwater.
in English is in the link below.
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