Sunday, January 16, 2011

If you think albedo loss means...

... you aren't interested in getting it on with the ladies, you might be a ... red-stater. Or a FReeper.

(The real condition of concern lady-wise is loss of libido. This post is not about that.)

New (but expected) news that the melting ice and snow of the polar regions, particularly the Arctic, is causing a positive feedback for global warming. Bright white areas reflect the vast majority of the energy of solar irradiance falling upon them. Darken those areas, either by soot deposition or melting, exposing darker land (on land) or darker sea (for sea ice) means more irradiance turns into heat and less gets reflected back into space.

All elementary, all figure-outable by even the densest neophyte. But what's going on?

"Satellite data indicated that Arctic sea ice, glaciers, winter snow and Greenland's ice were bouncing less energy back to space from 1979 to 2008. The dwindling white sunshade exposes ground or water, both of which are darker and absorb more heat.

The study estimated that ice and snow in the Northern Hemisphere were now reflecting on average 3.3 watts per square meter of solar energy back to the upper atmosphere, a reduction of 0.45 watt per square meter since the late 1970s."


And the envelope please...

" "This reduction in reflected solar energy through warming is greater than simulated by the current crop of climate models," he said of the findings by a team of U.S.-based researchers and published in the journal Nature Geoscience Sunday."

Radiative forcing and albedo feedback from the Northern Hemisphere cryosphere between 1979 and 2008 (links to the abstract; to read the whole thing, pay for it or subscribe to Nature Geoscience)

So... another article about this, even equipped with a diagram!

14% less solar energy reflected back into space

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