A recent study published in the journal Science suggests that the world’s largest lakes have experienced higher water loss over the last 30 years than previously estimated. The study found that both climate warming and human consumption of water have contributed to at least 50% of the decline in natural lakes, with artificial lakes and reservoirs also experiencing significant depletion. This trend poses a threat to drinking and agricultural supplies, plant and fish habitats, hydropower capacity, and marine tourism. Identifying the contributing factors and accurately tracking water trends could help inform water management strategies for up to two billion people.
Previous studies have had limited data, which has led to an underestimation of the global drought trend and an incomplete understanding of its causes. The study’s lead author, Fangfang Yao, says that the drying trends are more widespread than previously thought, affecting regions prone to drought as well as heavy rainfall.
The study found that lakes are warming rapidly, and that increased evaporation rates and longer drought recovery times could lead to even greater water storage problems in a warming climate. According to the study, climate warming and human water consumption contribute to 47-65% of natural lake volume decline. Meanwhile, sedimentation is the primary cause of reservoir depletion.
The study identifies several heavily populated areas, including the United States, Central Asia, the Middle East, western India, eastern China, northern and eastern Europe, northern Canada, southern Africa, most of South America, and Oceania, as experiencing significant water loss. However, some remote areas have seen notable increases in water storage.
The Colorado River in the United States is an area of particular concern, with Lake Powell and Lake Mead at historically low levels due to a prolonged drought and overuse. The U.S. Reclamation Service has released excess water from Lake Powell into Lake Mead in recent weeks, which benefits 25 million people by providing drinking and agricultural water. However, experts warn that this relief will be temporary, and the lakes will likely remain at capacity levels well below average.
Yao suggests that effective water conservation measures can help alleviate the effects of water loss resulting from overconsumption. Addressing climate change by reducing greenhouse gas emissions is also essential to mitigate its impacts on lake systems.