Over half the world’s lakes are drying up, scientists have found, and it’s mostly people’s playing with nature. A new paper published on Thursday in the Science, a reputed journal 53 percent of lakes worldwide have shrunk between 1992 and 2020. This level of water loss is equivalent to 17 Lake Meads, the authors say, which is the largest reservoir by volume in the U.S.
We would say this is a global pattern of drying,” lead author Fangfang Yao, a CIRES (Cooperative Institute for Research in Environmental Sciences) visiting fellow at the University of Colorado Boulder, and climate fellow at the University of Virginia. The drying is evident in both arid and humid regions, such as western Central Asia, the Middle East, western India, eastern China, northern and eastern Europe, Oceania, the conterminous United States, northern Canada, southern Africa, and most of South America. Yao and his fellow authors in their conclusion analyzed 250,000 lake-area snapshots of 1,972 of Earth’s biggest lakes—comprising 95 percent of lake water on the planet—captured by satellites over the past three decades. They also used long-term water level records to reduce uncertainty in their data. The authors combined water areas mapped from satellite imagery and water levels estimated from satellite altimeters to construct near-monthly lake volume time series from 1992 to 2020. Based on the time series data, they estimated the trends for Earth’s large water bodies. de-seasonalized the time series data and thus the seasonal fluctuations were removed before calculating the trends,” Yao said. Lake Mead one of the largest lakes reached record lows in the summer of 2022, potentially heading towards dead pool levels later this year, and the Great Salt Lake of Utah state in America also hit a record-low water level a few months ago, having lost 73 percent of its water. More than half of the net water loss in natural lakes is attributable to direct human impacts (i.e. human consumption) and indirect human impacts (e.g. climate warming),” Yao said.
For about 100 drying (large) lakes that were largely driven by warming, it is likely that the drying trends will be continued under a warmer climate. World’s freshwater lakes are responsible for storing 87 percent of the planet’s fresh water, and provide millions of people with essential drinking water and agricultural water. roughly one-quarter of the world’s population residing in drying lakes basins,” Yao explained. Drying lakes can cause freshwater loss, environmental degradation (e.g., impacts carbon dioxide emissions, receding shorelines, increasing salinity, deteriorating water quality, associated with level declines). A drying hydroelectric reservoir may lead to a reduction in hydropower energy generation. There may be other impacts on navigation, recreation…,” Yao said. If the lakes are not integrated with other water resources managed by public entities. This leads to over-exploitation and sub-optimal management.” “It is hard to resurrect a drying or dried lake. Hence, pre-empting this with smart management is essential. This is especially critical in a warmer world,” Rajagopalan said. He is co-author of the report and professor of hydrology and water resources in the University of Colorado Boulder Denver state in the USA.
The paper also discovered that 24 percent of lakes actually increased in their water storage, mostly in underpopulated areas in the inner Tibetan Plateau in Nepal and the U.S.’s Northern Great Plains, as well as in areas with newer reservoirs such as the Yangtze, Mekong, and Nile river basins. With the current trajectory of climate change, which is forecast to lead to a global average temperature increase of 2.7 degrees Celsius—around 5 degrees Fahrenheit—by the year 2100, this lake drying issue is only likely to get worse. Looking ahead, while it’s likely that changes in climate will continue, water management and the human consumption part is something that have to be under control,Ben Livneh, an associate professor of hydrology at the University of Colorado Boulder and co-author of the paper, Solutions must involve a combination of awareness—like what have been raised in this study, better monitoring, as well as actionable management that prioritizes healthy lake levels. good examples of management, like on the Colorado basin where specific water elevations trigger action, whereas bad examples are like the Aral Sea where unsustainable diversion led to a catastrophic loss of one of the world’s largest lakes,” Livneh said a co-author of the paper.
