August 24, 2009
Beetles, Wildfires Threaten Earth’s Carbon Sinks
Beetle infestations and rampant wildfires make for the perfect storm for the forested Arctic regions, which could make these carbon sinks become a massive carbon source.
"As far as the eye can see, it's all infested," forester Rob Legare told the Associated Press from the Alsek River valley in the Yukon Territory.Scientists say that global warming is the primary factor for the noticeable changes in effect among northern forests. As temperatures rise, conditions become drier and more insects are capable of weathering the warmer winters, which is a direct threat to the forested regions.
According to the Associated Press, average global temperatures rose 0.74 degrees Celsius (1.3 degrees Fahrenheit) over the past century. However, the northern regions saw about twice the rate of warming.
And scientists now fear that the warmer Arctic temperatures could turn the boreal forest away from being a carbon-absorbing region into a source of emissions with the threat of wildfires.
"These things may occur simultaneously," forest ecologist Scott Green from the University of Northern British Columbia told the AP.
"If the bark beetles kill the trees, you'll have lots of dead, dry wood that will create a really, really hot fire, and then sometimes you don't get trees regenerating on the site."
Cold winters of minus-40-Fahrenheit used to be all that was needed to kill beetle larvae, but as winter temperatures rise, so do the beetles' chances of survival.
Additionally, the summer drought conditions have led to weak, dry trees, with little or no defenses against the beetle infestation.
A beetle infestation has killed off millions of acres of pine forests in the US and Canada, and millions of spruce trees could be the next to go, according to researchers.
A climate bill passed by the House showed that the infestation could kill off millions of spruce trees, thus making it harder to meet a 17 percent reduction of carbon emissions from 2005 levels by 2020 and 83 percent by 2050.
The pine and spruce forests are natural storage facilities for carbon emissions, but as the beetles increase their territory, those trees could be lost, resulting in a massive carbon footprint. Healthy forests stand as a carbon sink, but then they die off, they emit the stored carbon back into the atmosphere.
"Pine beetle infestations are cyclical in nature and have been occurring for thousands of years but what is making things worse now is the effects of global warming," Rolf Skar, of Greenpeace, told Reuters earlier this month.
"If you don't have the real cold extremes to kill off the larvae under the bark you are going to have extreme infestation events," he added.
The infestations and threat of wildfires represent a possible setback for carbon storing initiatives.
As temperatures rise, so does the chance of wildfires. The Intergovernmental Panel on Climate Change (IPCC) issued a report in 2007 that found global warming would lead to an increase in wildfires.
This year, Harvard scientists studied the California wildfire season to show that fires could reach as far as 50 percent further by 2050.
"The bottom line is if you get more fire, you get more emissions, which contributes to further warming, which contributes to more fires," Mike Flannigan, a fire researcher for the Canadian Forest Service, told the AP.
"The concern is that things may happen more rapidly than we anticipate. Even our most pessimistic scenarios may not be pessimistic enough."
On the Net:
- Intergovernmental Panel on Climate Change
- University of Northern British Columbia