Climate Models Disagree on Strength of Carbon Land Sink Across Northern Eurasia
http://www.umass.edu/newsoffice/article/climate-models-disagree-strength-carbon[font face=Serif][font size=5]Climate Models Disagree on Strength of Carbon Land Sink Across Northern Eurasia[/font]
[font size=4]UMass Amherst climate scientist says models underestimate regions sequestration[/font]
July 28, 2015
Contact: Janet Lathrop 413/545-0444
[font size=3]AMHERST, Mass. In a new assessment of nine state-of-the-art climate model simulations provided by major international modeling centers, Michael Rawlins at the University of Massachusetts Amherst and colleagues found broad disagreement in the amount of atmospheric carbon dioxide (CO2) annually sequestered in tundra and boreal ecosystems of Northern Eurasia, a vast, understudied region of the world.
Rawlins also identified a trend among the nine models that shows the regions land carbon sink has been strengthening in recent decades, drawing in more carbon than expected, driven by increases in carbon uptake from plant growth that outweigh respiration increases. But lately, it shows signs of weakening.
As a group, the models tend to overestimate carbon emissions from land, particularly in autumn, he says. They generally underestimate the present-day carbon sink, in our view. So there is good news, in that the region is likely storing more of the carbon being emitted by human activities than the models depict. But the lack of agreement across the models is a concern.
He adds, Given the wide range in sink strength across the models, we are recommending that decision makers not rely on a single model for predicting what the future of the Arctic may be. This could lead to a very biased assessment. Findings appear in the current issue of Biogeosciences.
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