K-State study finds world's largest lakes are shrinking

MANHATTAN (KSNT) - Satellite images have shown Earth's largest lakes are shrinking due to climate change and human consumption, according to a Kansas State University study.

Lakes store 87% of the world's fresh water and changes in volume have repercussions for water sustainability, food security, waterbird habitats, carbon and nutrient cycling and recreation, according to a K-State press release.

Researchers at K-State analyzed around 2,000 of the world's largest lakes and found large declines in 53% of lakes between 1992 and 2020.

"We computed the trends of water volume, not surface area only, and then we unfolded the stories behind each in relation to major human and climatic drivers," Associate Professor of Geography and Geospatial Sciences Jida Wang said.

Researchers determined water loss was mostly due to climate warming, increased potential, human consumption and other effects. The main cause for loss for water reservoirs was sedimentation, according to the press release.

"We estimated that roughly one-quarter of the global population resides in basins with significant lake water loss," Wang said. "Effects can range from freshwater decline to environmental degradation, such as increased salt dust exposure, to hydropower reduction. These cautionary findings highlight the importance of accounting for climate change and sedimentation impacts when planning water policies to combat lake water declines."

Over the last two decades, Lake Sevan in Armenia had increases in water storage that researchers link to the enforcement of conservation laws, according to the study.

"While our results are specific to the large lakes we studied, we hope the findings motivate people to continue investigating the dynamics of important smaller lakes as well," Wang said.

The research team included collaborators from the University of Colorado Boulder, Kansas State University, France's space agency, the National Centre for Space Studies, King Abdullah University of Science and Technology and the International Institute for Applied Systems Analysis.

The team's findings were published in "Satellites Reveal Widespread Decline in Global Lake Water Storage" in the American Association for Advancement of Science publication, Science. K-State's Wang contributed to the study.