Global warming: Does albedo offset CO2?

Posted on October 20, 2011 by Bob Berwyn

New research may help fine-tune climate models

Large-scale forest disturbances like pine beetle outbreaks may change the albedo of an area and affect land-surface temperatures on a local and regional scale.

By Summit Voice

SUMMIT COUNTY — Scientists at Oregon State University say that, based on a recent study, some climate models need to revised to include changes in albedo resulting from large-scale forest disturbances.

Albedo is a measure of radiation reflected by a surface — in this case the surface of the planet. Lighter colors like snow reflect more light and heat back into space than the dark colors of a full forest and tree canopy.

Wildfire, insect outbreaks and hurricanes destroy huge amounts of forest every year and increase the amount of carbon dioxide entering the atmosphere, but in higher latitudes where snow is common, those disturbances can result in more heat being reflected back into the atmosphere instead of being absorbed. (more…)

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Loss of polar sea ice to amplify global warming

Posted on January 24, 2011 by Bob Berwyn

Scientists track the state of the polar icecap on a daily basis. Melting ice will cause sea levels to rise and could also speed up the global warming effects of greenhouse gases, as less ice means more heat will be absorbed by darker-colored oceans. Click on the image to visit The Cryosphere Today website.

Previous research may have underestimated impacts of loss of reflectivity

By Summit Voice

SUMMIT COUNTY — Loss of sea ice cover in the Arctic could amplify global warming trends much more than previously believe, according to a new study funded by the National Science Foundation. The research analyzed the albedo feedback in the Northern Hemisphere during a three-decade span, concluding that the region’s loss of reflectivity due to snow and sea ice decline is more than double what state-of-the-art climate models estimate.

The study was published online last week in Nature Geoscience.

“The cryosphere isn’t cooling the Earth as much as it did 30 years ago, and climate model simulations do not reproduce this recent effect,” said Karen Shell, an Oregon State University atmospheric scientist and one of the authors of the study. “Though we don’t necessarily attribute this to global warming, it is interesting to note that none of the climate models used for the 2007 International Panel on Climate Change report showed a decrease of this magnitude.” (more…)

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