Friday, March 01, 2013

Settled science: "The trouble is that air does not get sealed in the ice until hundreds or even thousands of years after the snow has fallen, as it slowly gets buried and compressed."

At Ice Age End, a Smaller Gap in Warming and Carbon Dioxide - NYTimes.com
A meticulous new analysis of Antarctic ice suggests that the sharp warming that ended the last ice age occurred in lock step with increases of carbon dioxide in the atmosphere, the latest of many indications that the gas is a powerful influence on the earth’s climate.
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Mainstream climate scientists rejected that view and argued that carbon dioxide, while it certainly did not initiate the end of the ice age, played a vital role in the feedback loops that caused a substantial warming.
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The trouble is that air does not get sealed in the ice until hundreds or even thousands of years after the snow has fallen, as it slowly gets buried and compressed.
That means the ice and the air bubbles trapped in it are not the same age, so it becomes tricky for scientists to put reconstructed atmospheric composition and reconstructed temperature onto a common time scale.
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“We’re just entering a new era in earth’s history,” Dr. Shakun said. “It will be an unrecognizable new planet in the future. I think the only question is, exactly how fast does that transformation happen?”

1 comment:

chris y said...

So the air trapping process is not so settled after all? The assumption has been that the mixing process is done after 50 - 100 years, in order to match ice core CO2 with post-1950's direct measurements of CO2.

If you accept the proposed ice bubble closure time of 1000's of years, then the ice core CO2 has had centennial peak-to-peak fluctuations bulldozed smooth, giving the false impression that CO2 fluctuations were always small.