New research indicates that lakes in the Northern Hemisphere reflect more sunlight than surrounding land, contributing significantly to the planet's cooling effect.
Key facts
- •The study analyzed 22 years of satellite observations across the Northern Hemisphere.
- •Lakes provide a cooling effect of −14.4 watts per square meter, compared to −8.2 watts per square meter for land.
- •The cooling contribution of lakes is most significant during the transition from winter to late spring.
- •In boreal forest regions, lakes can account for over one-quarter of the total cooling effect from snow and ice.
- •Researchers recommend that climate models better distinguish between lake surfaces and surrounding land to improve energy balance calculations.
A study led by Dr. Sarah Cooley of Duke University suggests that lakes play a larger role in regulating Earth's climate than previously understood. By analyzing 22 years of satellite data, researchers found that lakes in the Northern Hemisphere have a stronger cooling effect than the surrounding land due to their ability to reflect sunlight.
By the numbers
Cooling effect of lakes
The study, published in Geophysical Research Letters, found that lakes provide a cooling effect of −14.4 watts per square meter, compared to −8.2 watts per square meter for surrounding land. This effect is particularly notable in boreal forests across North America, Europe, and Asia, where lakes can account for more than 25% of the total cooling effect from snow and ice.
Why lakes reflect more energy
Lakes maintain a higher cooling effect for two primary reasons: they retain reflective snow and ice longer than land in the spring, and they possess a higher albedo, meaning they reflect a greater proportion of incoming sunlight. Because land often loses its snow cover earlier, it begins absorbing solar energy while nearby lakes remain reflective, creating a significant difference in seasonal energy balance.
Implications for climate models
Researchers argue that current climate models often fail to distinguish the specific contribution of lakes from that of the surrounding land. While these findings do not offset global warming, the team suggests that incorporating lake-specific data into climate models will improve the accuracy of predictions regarding how the Earth system responds to environmental changes.
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This article was independently rewritten by ManyPress editorial AI from reporting originally published by Phys.org.
