The water reserves in our lakes are dwindling concludes an international team of researchers in Science Magazine. They note that more than half of the world’s largest lakes are losing significant amounts of water, often due to human influence. A deeper understanding of the reasons may help preserve these vital ecosystems and maintain their function as water reservoirs.
Even though lakes make up only about three percent of the global land mass, they host more than 85 percent of the planet’s liquid freshwater. These natural reservoirs provide water for people and agriculture and keep vital ecosystems running. Although the disappearance of water is not new, detailed information about its extent and exact causes has been lacking.
Scientists have now combined satellite data with hydrological and climatic models to record and estimate changes in the water volume of 1972 lakes and reservoirs worldwide. These data cover the period from 1992 to 2020. The study shows that 53 percent of the water bodies studied have lost significant water over the past 28 years. The affected regions are worldwide, from western Asia to South America.
The world’s lakes and reservoirs lose 602 cubic kilometers each year
Water volume increased in only about a quarter of the lakes and reservoirs studied, mainly in sparsely populated areas such as the Inner Tibetan Plateau and the northern Great Plains in North America.
The study indicates that the world’s major lakes and reservoirs lost 22 gigatons, or about 602 cubic kilometers, each year. This is equivalent to the water consumed by the United States in all of 2015, or 17 times the volume of Lake Mead, the largest reservoir in the United States. Global water loss is thus about 40 percent higher than the annual natural variations in the water bodies studied.
Researchers blame climate change and the associated increase in evaporation, as well as water consumption by humans, for the significant loss of water in natural lakes. These two influences are mainly responsible for the declining water volume in about 100 large lakes worldwide. Many of these consequences of human activities and climate change on water loss in lakes are new findings revealed through the study.