Cloud cover and climate change


in Geek stuff, Science, The environment

Musician at Raw Sugar Cafe

According to research published back in April, the biggest climate changes in the 21st century may occur more due to changes in high altitude cloud cover, in response to increased temperatures from rising greenhouse gas concentrations, rather than due to the initial temperature increases themselves: Global warming due to increasing absorbed solar radiation, published in Geophysical Research Letters.

Reduced cloud cover would reduce the amount of sunlight that gets reflected back into space, rather than striking the surface of the Earth. As such, it would produce further warming. Based on evaluation of simulations used in preparing the Fourth Assessment Report of the IPCC, this effect may be of greater magnitude than the initial warming due to increased absorption of outgoing long-wave radiation by greenhouse gasses.

While the result certainly cannot be considered definitive now, it underscores the importance of improving climate models and incorporating the key feedback effects into them. Only when that has been done can more precise estimates of the climatic sensitivity of the planet be produced, as well as more accurate regional projections.

{ 1 comment… read it below or add one }

R.K. May 19, 2009 at 1:44 pm

This is scary, because it suggests we might be estimating climatic sensitivity quite badly. It’s like we are pressing against a wall, thinking it has a certain strength, while we really don’t know what it is made of or how it will respond to increased pressure.

Given how bad it would be for the ‘wall’ to fail, this new uncertainty provides even more reason to stop pushing as rapidly as possible.

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