NASA study at BU: Amplified Greenhouse Effect Shifts North's Growing Seasons
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Alex Brown
Mar 11, 2013, 5:22:58 AM3/11/13
to Listserve UML Climate
03/10/2013 12:00 AM EST
Vegetation
growth at Earth's northern latitudes increasingly resembles lusher
latitudes to the south, according to a NASA-funded study based on a
30-year record of land surface and newly improved satellite data sets.
http://www.nasa.gov/home/hqnews/2013/mar/HQ_13-069_Northern_Growing_Seasons.html
http://www.nasa.gov/home/hqnews/2013/mar/HQ_13-069_Northern_Growing_Seasons.html
Alex Brown
Mar 11, 2013, 11:30:16 PM3/11/13
to kirtg...@sbcglobal.net, Listserve UML Climate
Kirt Griffin wrote:
Yes, that's well understood and part of the story -- but it's a story about Yellowknife, not Atlanta. Circumpolar warming is far greater than in mid-latitudes and tropics: atmosphere and ocean circulation transports heat to polar regions, with surface area far smaller than the regions at lower latitudes where it's collected -- so greenhouse heat increases, due to global atmospheric CO2 change, become concentrated in the Arctic, resulting in shorter snow cover seasons, more heat collected during Arctic summers, longer growing seasons, and advance of the treeline to regions that were treeless thirty years ago. Thawing of permafrost liberates methane (aka natural gas), 30x worse than CO2 as a greenhouse gas. All that lost snowcover means absorption of solar radiation which was previously reflected back to the sky. Loss of sea ice will also result in absorption by the Arctic Ocean. The whole system is full of the wrong kind of feedback - which is what "tipping point" is all about. This is a gigantic experiment. We seem to have no idea what we've done to this planet despite more than fifty years of very solid science and warnings about fossil fuel energy consumption -- see http://www.aip.org/history/climate.
Hi Alex,I guess there was no consideration that more CO2 causes more vegetative growth. I know my forest is going gangbusters.Cheers,Kirt
Yes, that's well understood and part of the story -- but it's a story about Yellowknife, not Atlanta. Circumpolar warming is far greater than in mid-latitudes and tropics: atmosphere and ocean circulation transports heat to polar regions, with surface area far smaller than the regions at lower latitudes where it's collected -- so greenhouse heat increases, due to global atmospheric CO2 change, become concentrated in the Arctic, resulting in shorter snow cover seasons, more heat collected during Arctic summers, longer growing seasons, and advance of the treeline to regions that were treeless thirty years ago. Thawing of permafrost liberates methane (aka natural gas), 30x worse than CO2 as a greenhouse gas. All that lost snowcover means absorption of solar radiation which was previously reflected back to the sky. Loss of sea ice will also result in absorption by the Arctic Ocean. The whole system is full of the wrong kind of feedback - which is what "tipping point" is all about. This is a gigantic experiment. We seem to have no idea what we've done to this planet despite more than fifty years of very solid science and warnings about fossil fuel energy consumption -- see http://www.aip.org/history/climate.
--- On Mon, 3/11/13, Alex Brown <alexbr...@gmail.com> wrote:
Amplified Greenhouse Effect Shifts North's Growing Seasons03/10/2013 12:00 AM EST
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