Sharon Stammerjohn

Polar amplification is the idea that under global climate change, polar regions experience much greater temperature change than the rest of the planet.  This amplified response is largely attributed to strong positive feedbacks, which are feedbacks that amplify the initial perturbation or change (in contrast to negative feedbacks which tend to dampen the initial perturbation). 

An example of a strong positive feedback in polar regions is the ice-albedo feedback.  Ice and snow reflect anywhere from 50% to 90% of the sun’s energy (meaning their albedo is anywhere from 0.5 to 0.9), while an ice-free ocean has a much lower albedo.  Therefore, when the coverage of sea ice decreases, for example, the amount of solar energy absorbed by the ocean increases quite significantly, causing more sea ice to decrease.  Given that, are current changes in sea ice indicating that the ice-albedo feedback has been activated? 

We will explore this question by comparing how sea ice is changing in both polar regions and discuss whether these changes are evidence of polar amplification of climate change.

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Sharon Stammerjohn

Polar amplification - What is it, and is it happening now?

October 21, 2010
4-5pm
Current Periodicals Room
Science & Engineering Library