More than half of the world’s largest lakes have shrunk over the past three decades, researchers report.
This is a big problem for people who depend on these lakes for drinking water and irrigation. The drying up of lakes also threatens the survival of local ecosystems and migratory birds and can even cause unhealthy dust storms.
“About a quarter of the Earth’s population lives in these lake water loss basins,” says surface hydrologist Fanfang Yao of the University of Virginia in Charlottesville.
Using satellite observations from 1992 to 2020, Yao, then at the University of Colorado at Boulder, and his colleagues estimated the area and water level almost 2,000 freshwater bodies of water . This work provided a continuous stream of lake volume measurements. Lakes make up 96 percent of the total natural reserve of the Earth’s lakes and 83 percent – in reservoirs. The team also used population data to estimate the number of people living near drying lakes.
The researchers found that approximately 53 percent of the world’s lakes have clearly shrunk, while only 22 percent have made progress. Approximately 600 cubic kilometers of water were lost from these reservoirs over a period of 28 years. That’s about 17 times the maximum capacity of Lake Mead, the largest reservoir in the United States.
The researchers used hydrological and climate modeling to determine the processes that influence the fluctuations of water bodies. They found that climate change and human consumption were the main reasons for the decline in natural lakes, while in reservoirs sediment accumulation was the main factor in the loss of stocks.