Wednesday, April 04, 2012

Positive Feedback Writ Large


Just a very short post. Seems the mystery of CO2 emissions into the atmosphere causing massive heat gain in the earth (50 millions years ago as example) has been solved, a finding with direct consequences to what is happening today as we spew out ever more amounts of CO2 into the air without regard for the inevitable blow back we will soon be facing.


"The standard hypothesis has been that the source of carbon was in the ocean, in the form of frozen methane gas in ocean-floor sediments," DeConto says. "We are instead ascribing the carbon source to the continents, in polar latitudes where permafrost can store massive amounts of carbon that can be released as CO2 when the permafrost thaws."


The new view is supported by calculations estimating interactions of variables such as greenhouse gas levels, changes in the Earth's tilt and orbit, ancient distributions of vegetation, and carbon stored in rocks and in frozen soil.


While the amounts of carbon involved in the ancient soil-thaw scenarios was likely much greater than today, implications of the study appear dire for the long-term future as polar permafrost carbon deposits have begun to thaw due to burning fossil-fuels, DeConto adds. "Similar dynamics are at play today. Global warming is degrading permafrost in the north polar regions, thawing frozen organic matter, which will decay to release CO2 and methane into the atmosphere. This will only exacerbate future warming in a positive feedback loop."

The picture below shows how positive feedback works.



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