The world’s lakes are warming at a faster rate than oceans and atmosphere, a trend that may already have triggered major changes in aquatic ecosystems, according to a new report published in Geophysical Research Letters on Wednesday.
Globally, lakes have been heating up an average of 0.34°C (.61°F) per decade between 1985 and 2009, researchers found. In northern climates, the deepest ice-covered lakes are warming at twice the rate of the atmosphere.
“The widespread warming reported here suggests that large changes in Earth’s freshwater resources and their processes are not only imminent but already under way,” the study concludes.
When lakes warm, their productivity decreases and they become more likely to form toxic algae or become vulnerable to damage by invasive species. That, in turn, threatens delicate ecosystems within the lake, including fish and other wildlife, which can lead to water insecurity, “substantial economic consequences,” and, in some cases, “complete ecosystem loss,” the study states.
The global average lake surface warming rate during summer seasons implies a 20 percent increase in algal blooms and a five percent increase in toxic algal blooms over the next century, researchers found. That could ramp up dangerous methane gas emissions by 4 percent over the next decade.
“Lakes hold a large majority of Earth’s liquid freshwater, support enormous biodiversity, and provide key provisioning and cultural ecosystem services to people around the world. Climate change is among the greatest threats to lakes,” the study states. “The pervasive and rapid warming observed here signals the urgent need to incorporate climate impacts into vulnerability assessments and adaptation efforts for lakes.”
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