A recent study published in the journal Science reveals that more than 50% of the world’s largest lakes are experiencing a decline in water levels. The primary factors contributing to this global trend include climate change, unsustainable human consumption, and sedimentation. Researchers conducted a comprehensive analysis of 1972 major lakes using satellite observations, climate data, and hydrologic models spanning three decades. They examined approximately 250,000 snapshots of lake areas captured by satellites during this period.
The study found statistically significant decreases in water storage for 53% of the largest lakes between 1992 and 2020. This decline in water volume amounts to approximately 17 times the capacity of Lake Mead, the largest reservoir in the United States. The researchers identified increasing evaporative demand as a significant factor driving water loss. Evaporative demand refers to the potential water loss from the lake’s surface due to atmospheric conditions such as temperature, wind speed, humidity, and cloud cover. Additionally, growing human water consumption and sedimentation further contribute to the deterioration of these lakes.
The study highlights that both lakes in dry and wet regions are experiencing diminishing volumes, with humid tropical and Arctic lakes exhibiting more extensive drying patterns than previously recognized. Alarmingly, approximately one-quarter of the global population resides in the basin of a shrinking lake. Furthermore, the researchers note that around 43% of the drying lakes were influenced, at least partially, by climate change, as water loss is predominantly driven by changes in temperature, potential evapotranspiration, or runoff.
This study sheds light on the concerning decline in water levels observed in many of the world’s largest lakes. Urgent measures are needed to address climate change, promote sustainable water consumption, and mitigate sedimentation to safeguard these crucial freshwater resources and the ecosystems they support.