More than half of the world’s major lakes and reservoirs are drying up. A new studybased on satellite images, verified that 53% of these water surfaces have been decreasing significantly since 1992. And yes, it’s partly our fault.
From the Caspian Sea, located between Europe and Asia, to Lake Titicaca in South America. The accumulated water loss is equal to 22 gigatons per year for almost three decades. For perspective, it is as if Lake Mead, the largest reservoir by volume in the United States (about 30 km³ of water), had dried up 17 times.
Fangfang Yao, a hydrologist at the University of Virginia and director of the study, explained that global warming and excessive human consumption are the main causes.
Yao and his team they assessed nearly 2,000 lakes, They comprise 95% of all the water in lakes on the planet.. they collected 250 thousand images of these surfaces and their surroundings taken between 1992 and 2020. The material was analyzed with the support of climatic and hydrological models.
Lakes are drying up in all regions
The research, published in the journal Science, determined that human consumption is drying up lakes such as the Aral Sea, in Central Asia, and the Dead Sea, in the Middle East. While the increase in temperatures is affecting surfaces in Afghanistan, Egypt and Mongolia to a greater extent. But the drought reaches all regions.
One of the great findings of the study is that these water sources are declining in both the wet and driest regions of the world. Decreases were found in humid tropical lakes in the Amazon, as well as in areas of the Arctic.
The research also highlights that 25% of the world’s population lives in a lake basin that is on a downward trend. It means that the drought is directly affecting around 2 billion people.
“More than half of the net water loss in natural lakes is attributable to direct human impacts and indirect human impacts,” Yao told Newsweek. Balaji Rajagopalan, co-author of the study, pointed out that smart management is urgently needed to curb the problem. “It is difficult to revive a lake that is drying up or has already dried up… This is especially critical in an increasingly warming world,” he added.
From alarm to action
The World Meteorological Organization warned this week that global warming is likely will exceed the temperature limit of 1.5ºC in the next 5 years. The consequences are already impacting the entire planet: impressive heat waves, unprecedented droughts and the extinction of various species. But beyond that threshold, experts say, everything would be much more difficult to control.
The study on the drought of the lakes has good news. While most of the world’s lakes are drying up, 24% of those studied experienced significant increases in water storage. Many of them are in unpopulated areas: inland on the Tibetan Plateau and the great northern plains of North America. Also in regions with new reservoirs, such as the Yangtze, Mekong and Nile river basins.
One of the lakes that grew was Sevan, located in Armenia. It is an exemplary case. Since the 2000s, the authorities are implementing conservation laws on the extraction of water in the place. “If human consumption is a major factor in declining lake water storage, then we can adapt and explore new policies,” explained Ben Livneh, another research participant. Here, a hint of where to start working.