(PhysOrg.com) -- Alaskan forests used to be important players in Mother Nature’s game plan for regulating carbon dioxide levels in the air. It’s elementary earth science: Trees take up carbon dioxide and give off oxygen.
But now, American and Canadian researchers report that climate change is causing wildfires to burn larger swaths of Alaskan trees and to char the groundcover more severely, turning the black spruce forests of Alaska from repositories of carbon to generators of it. And the more carbon dioxide they release, the greater impact that may have in turn on future climate change.
EDIT
During their study, Kane and colleagues collected data on the depth of ground-layer combustion in 31 Alaskan black spruce forest and peatland fires at 178 sites. Black spruce forests cover two-thirds of all woodlands in the interior of Alaska. They found that when larger areas burned, the severity of the damage—measured by the depth of burning—was high throughout the fire season. Also, the carbon emissions were greater. In fact, the researchers found that the annual carbon losses from forest fires in 2000 to 2009 were more than twice the carbon lost during each of the previous five decades.
Climate change is an undeniable fact in the Arctic, where Arctic sea ice in January 2011 covered 5.23 million square miles, the lowest January ice measurement since satellite records began in 1979, and air temperatures over much of the Arctic were 4 to 11 degrees above average. These climate conditions are already thawing the permafrost, where the northern forests sequester much of their carbon intake. The researchers say that an increase in area burned and severity of fires is likely to increase that permafrost loss, in turn accelerating the negative effects of climate change.
EDIT
http://www.physorg.com/news/2011-02-frequent-severe-alaskan-forests-carbon.html
Printer-friendly format
Email this thread to a friend
Bookmark this thread
(1000+ posts)
Send PM |
Profile |
Ignore
