By Gloria Dickies
LONDON (RockedBuzz via Reuters) – More than half of the world’s major lakes and reservoirs have shrunk since the early 1990s, mainly due to climate change, heightening concerns about water for agriculture, energy hydropower and human consumption, according to a study released Thursday.
A team of international researchers has reported that some of the world’s most important sources of fresh water – from the Caspian Sea between Europe and Asia to Lake Titicaca in South America – have been losing 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 body of water in the United States.
Fangfang Yao, a surface hydrologist at the University of Virginia who led the study in the journal Science, said 56% of the decline in natural lakes was driven by climate warming and human consumption, with warming “the share greater”.
Climate scientists generally think that the world’s dry areas will get drier as a result of climate change and wetlands will get wetter, but the study found significant water loss in wet regions as well. “This shouldn’t be overlooked,” Yao said.
Scientists evaluated nearly 2,000 large lakes using satellite measurements combined with climate and hydrological models.
They found that unsustainable human use, changes in rainfall and runoff, sedimentation and rising temperatures lowered lake levels globally, with 53% of lakes showing a decline from 1992 to 2020 .
Nearly 2 billion people living in a drying lake basin are directly affected and many regions have faced shortages in recent years.
Scientists and activists have long argued that global warming beyond 1.5 degrees Celsius (2.7 degrees Fahrenheit) needs to be prevented to avoid the more catastrophic consequences of climate change. The world is currently warming at a rate of about 1.1°C (1.9°F).
Thursday’s study found that unsustainable human use 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 the loss of water to the atmosphere.
Water levels have risen in a quarter of the lakes, often due to dam construction in remote areas such as the Inner Tibetan Plateau.
(Reporting by Gloria Dickie in London; editing by Barbara Lewis)