Overlooked lakes may be helping to keep the Northern Hemisphere cool
Lakes may cover only a small fraction of Earth's surface, but new research suggests they play a bigger role in regulating the planet's climate than previously recognized. By reflecting sunlight back into space when covered in snow and ice, lakes in the Northern Hemisphere have a stronger cooling effect than the surrounding land.
Research published in Geophysical Research Letters reveals that lakes in the Northern Hemisphere play a more significant role in climate regulation than previously thought. Lakes, which cover only a small portion of Earth's surface, have a stronger cooling effect per square meter than the surrounding land due to their ability to reflect sunlight back into space when covered in snow and ice.
The study, led by Dr. Sarah Cooley of Duke University and colleagues, analyzed 22 years of satellite observations comparing seasonal snow cover and sunlight reflection between lakes and nearby land in the Northern Hemisphere. The findings show that lakes contribute more to the reflection of sunlight than their limited surface area would suggest, particularly in boreal forests where they account for over a quarter of the cooling effect.
This effect becomes especially pronounced in late spring when snow and ice are starting to melt, allowing lakes to continue reflecting sunlight while the surrounding land absorbs more of the sun's energy. The researchers emphasize that these findings highlight an overlooked part of Earth's climate system that should be better represented in climate models.
While acknowledging that lakes cannot offset global warming, the study underscores the importance of considering this component alongside other factors affecting the planet's energy balance and future climate.
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