Environment
Climate crisis
Global warming and human consumption: half of the world's great lakes are drying up
Research published in Science by an international group of scientists based on satellite observations
19/05/2023
Reuters
More than half of the world's great lakes and reservoirs have shrunk dramatically since the early nineties, largely due to climate change. These are the results of a new study just published in Science.
Lakes in areas with the highest rainfall are also shrinking. This is due both to rising temperatures that produce more evaporation, and due to a society that is increasingly thirsty and absorbs water from lakes for agriculture, power plants and drinking water supplies.
A team of international researchers assessed nearly 2,000 large lakes using satellite measurements combined with climate and hydrological models.
According to the research, some of the world's most important freshwater sources — from the Caspian Sea, between Europe and Asia, to Lake Titicaca, in South America — have lost water at a cumulative rate of about 22 gigatons per year for nearly three decades.
That's about 17 times the volume of Lake Mead, the largest reservoir in the United States.
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In the study first authored by Fangfang Yao, a surface hydrologist at the University of Virginia, it is claimed that 56% of the decline of natural lakes was determined, for the most part, by global warming and human consumption.
Unsustainable use of water resources has dried up lakes such as the Aral Sea in Central Asia and the Dead Sea in the Middle East, while lakes in Afghanistan, Egypt and Mongolia have been affected by rising temperatures, which can increase water dissipation in the atmosphere.
Climate scientists generally think that arid areas of the world will become drier due to climate change, while wetlands will become wetter, but the study found significant water loss even in non-humid regions. A fact that "should not be overlooked," says Yao.
According to the research, unsustainable use, changes in rainfall and runoff, sedimentation and rising temperatures drove down the overall level of lakes, with 53% of basins experiencing a decline from 1992 to 2020.
Almost 2 billion people live in a lake basin that is drying up and suffer the consequences.