Friday, August 9, 2013

Hawai`i research: Climate change with us for seven generations, or more

University of Hawai`i researchers, after studying previous climate cycles, conclude that climate change will be with us a long, long time.

And it’s because of our persistent use of carbon-based fuels, said University of Hawaiʻi at Mānoa oceanographer Richard Zeebe in a paper in the Proceedings of the National Academy of Sciences. A press releaseon the paper is here.

(Image: Earth, from space. Credit: NASA.)

That carbon use has driven the atmospheric carbon-dioxide  index from 280 to 400 parts per million since the start of the industrial age. And that in turn will drive further warming, whose impacts will include continued melting of large ice sheets and resulting sea level rise.

Zeebe looked at the feedback in the climate system caused by such warming. There are faster feedback mechanisms like snow cover and clouds (as snow and cloud cover change, the amount of solar radiation reflected away from the planet also changes.) But there are slower feedback mechanisms as well, including impacts from changing vegetation patterns. And some of those changes could extend for centuries, he calculated

“The calculations showed that man-made climate change could be more severe and take even longer than we thought before… We need to put the impact that humans have on this planet into a historic and geologic context.” Zeebe said.

“By continuing to put these huge amounts of carbon dioxide in the atmosphere, we’re gambling with climate and the outcome is still uncertain.  The legacy of our fossil fuel burning today is a hangover that could last for tens of thousands of years, if not hundreds of thousands of years to come.”

© Jan TenBruggencate 2013

Citation: Zeebe, R. E., Time-dependent climate sensitivity and the legacy of anthropogenic greenhouse gas emissions, Proceedings of the National Academy of Sciences, 110, doi:10.1073/pnas.1222843110, Aug 05, 2013.

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