Over half of the world’s largest lakes and reservoirs now hold less water than they did three decades ago.
Researchers have found that the main causes are climate change and human activities, according to a study published in the Journal Nature on May 18, 2023. Only around a quarter of lakes and reservoirs now store more water than in 1992.
The scientists used three decades of satellite observations, climate data, and hydrologic models dating back to 1992, and while the news seems to be bleak, this new method can help water managers and communities make better decisions.
Water levels of 1,972 of the world’s largest lakes were tracked between 1992 and 2020. Researchers found that 53 percent of the lakes lost water over this period, with the total loss equivalent to 17 Lake Meads, America’s largest reservoir.
Lead author Fangfang Yao, a CIRES visiting fellow, now a climate fellow at the University of Virginia, said, “This is the first comprehensive assessment of trends and drivers of global lake water storage variability based on an array of satellites and models.”
“This suggests that the drying trend worldwide is more extensive than previously thought,” Yao added.
The effects of climate change are more pronounced
Previous research tends to show a pattern of dry regions becoming drier and wet regions becoming wetter, as the effects of climate change become more prominent, Live Science is reporting.
But the new research shows that lakes are drying up in the humid tropics as well as in arid regions. “This suggests that the drying trend worldwide is more extensive than previously thought,” Yao said.
The loss of lake water is a serious problem, according to the research team. Lakes and reservoirs provide important sources of water for drinking, irrigation, hydropower, and recreation.
The lakes’ ecosystem also suffers, leaving fish populations and migrating birds at risk when the water runs low. And when salt lakes – such as Utah’s Great Salt Lake – dry up, the newly exposed lakebed can become a source of toxic dust storms that degrade nearby soil and cause health problems.
Whether Earth’s lakes will continue drying depends on the complex interaction of various factors. But this new study can give us some idea of what might happen under various circumstances, Yao said.
Yao says that the impact of warming and human water consumption could become problematic. “If we continue [with] business as usual and withdraw the water to meet our maximum needs, we’ll make the situation worse,” he said.
