Light colors reflect heat from the sun, which is why light-colored clothes help keep us cool in hot weather.


The earth is affected in the same way. White snow and ice reflect the sun and keep the planet cool. Dark surfaces, however, like the open ocean or forests absorb sunlight and heat up. Scientists call this the albedo effect.

This is important because the loss of sea ice in the Arctic is changing the global albedo.

Meier: “Nearly a million square miles has changed from being ice covered, where 70-80 percent of the sun’s energy is reflected, to now being open ocean where less than 10 percent is being reflected.”

That’s Walt Meier, a research scientist at NASA Goddard Space Flight Center. He says this changing albedo effect is accelerating climate change in the Arctic.

As the ice melts, the darker ocean underneath warms up — which melts more ice, which further warms the ocean, which melts more ice, in a spiraling feedback loop.

Meier says the Arctic acts like a global air conditioner, helping to keep the entire earth cool. The loss of Arctic sea ice is like losing your air conditioner during a heat wave — and it will make global warming worse.


This flow of energy from the Sun to the Earth might help view energy reflectance and absorption, from a presentation by Kevin Trenberth of NCAR (source:

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The Arctic Brings Surprises, but the Trend Remains Clear

Reporting credit: ChavoBart Digital Media.
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A regular contributor to Yale Climate Connections since 2012, David Appell, Ph.D., is a freelance writer living in Salem, Oregon, specializing in the physical sciences, technology, and the environment. His...