LONDON - Climate change is the main cause behind the shrinking of over half of the world's large lakes and reservoirs since the early 1990s, raising concerns about water availability for agriculture, hydropower, and human consumption. According to a recent study, important freshwater sources like the Caspian Sea and Lake Titicaca have experienced a cumulative water loss of approximately 22 gigatonnes per year for almost 30 years. This is equivalent to about 17 times the volume of Lake Mead, the largest reservoir in the United States.

In a study published in the journal Science, led by Fangfang Yao from the University of Virginia, it was found that 56% of the decline in natural lakes is attributed to climate warming and human consumption, with climate warming being the primary driver. While it is commonly believed that arid regions will become drier and wet regions wetter due to climate change, the study revealed significant water loss even in humid areas, emphasizing the importance of this finding. The researchers evaluated nearly 2,000 large lakes by analyzing satellite measurements in conjunction with climate and hydrological models.

According to the study, unsustainable human activities, changes in precipitation and run-off patterns, sedimentation, and increasing temperatures have been the driving factors behind the global decline in lake levels. From 1992 to 2020, around 53% of lakes experienced a decrease in water levels. This has directly impacted nearly 2 billion people living in drying lake basins, leading to water shortages in various regions.

Scientists and activists have long emphasized the need to limit global warming to no more than 1.5 degrees Celsius (2.7 degrees Fahrenheit) to avert the most severe consequences of climate change. The current rate of warming is approximately 1.1 degrees Celsius (1.9 degrees Fahrenheit).

The study highlighted that unsustainable human practices have caused the drying up of lakes such as the Aral Sea in Central Asia and the Dead Sea in the Middle East. Additionally, rising temperatures have negatively affected lakes in countries like Afghanistan, Egypt, and Mongolia, as higher temperatures lead to increased water loss to the atmosphere.

A quarter of the lakes analyzed in the study experienced an increase in water levels, which was frequently attributed to the construction of dams in remote regions like the Inner Tibetan Plateau.