Positive feedbacks are one of the most worrisome aspects of climate change. Viscious spirals could make controlling the problem far more difficult and, if we wait too long to act, potentially impossible to deal with. A new article in Nature suggests that the pine beetle epidemic in British Columbia has turned the forests there into net carbon emitters:
In the team’s model, a pine forest untouched by beetles but with a normal amount of logging is a slight carbon sink, sucking up more carbon (as carbon dioxide) than it loses (either as carbon dioxide or as timber). The only exception to this is when forest fires convert the forest to a net source, as they did in 2003. The beetles have an even bigger effect — in their worst year releasing 50% more carbon than the 2003 fires — and act over longer time scales, with additional logging making things even worse.
According to Werner Kurz, Natural Resources Canada’s senior research scientist, the total emissions associated with the outbreak will be about 990 megatonnes by 2020 – about 1.5 years worth of total Canadian emissions at present levels.
Eventually, the pine beetles will find themselves in the position of having nothing left to eat and the epidemic will taper off. What is nevertheless suggested by this situation is the possibility that climate change can lead to degraded ecosystems which hold less carbon dioxide, thus further contributing to climate change.
An even worse pine beetle epidemic could occur if temperatures warm enough to let it invade the boreal forest.
FORESTRY: CAP AND TRADE
Tiny beetle tramps over emission targets
PATRICK BRETHOUR
pbrethour@globeandmail.com
April 25, 2008
“Next year, those decaying logs will emit 73 megatonnes of carbon dioxide – more than the entire economy of British Columbia, which is likely to clock in at something just over 70 megatonnes. Werner Kurz, senior research scientist with Canadian Forest Service at Natural Resources Canada, says the carbon output from forests will fall through the next decade; by 2020 it should only be only 37 megatonnes.
To put that in perspective, B.C. is hoping, through its ground-breaking carbon tax and a wide-ranging carbon trading system, to reduce emissions by around 24 megatonnes. Clearly, if B.C. has to account for the pine beetle burden, its climate change goals will become a fantasy.”
Nature Reports Climate Change
Published online: 24 April 2008 | doi:10.1038/climate.2008.35
Plight of the pines
Brian Hoyle
Under attack from pine beetles that are thriving in a warmer climate, Canada’s boreal forests could become a sizeable source of emissions in the coming decade. Brian Hoyle reports.
In most temperate regions of North America, a vivid green expanse of forest patchworked with bright red signals a healthy forest in autumn, but in Canada’s British Columbia this visual delight masks an insidious invasion. Under siege by a culprit other than the two-legged human logging variety, lodge-pole pine trees are turning red — and dying — by the dozen.
According to the new calculations, by 2020 the beetle outbreak alone will have released 270 megatonnes of carbon dioxide into the atmosphere. That’s exactly the amount of greenhouse gas emissions that Canada is committed to reducing by 2012 under the Kyoto Protocol. And given that Canada is far off meeting that target, it may be even harder than once thought for the nation to offset its emissions through forest management. Putting it in context, Kurz says, “The predicted emissions are larger than the total average sink of all of Canada’s managed forest over the last decade.”
stavrosthewonderchicken’s home is dying
By gen on canada
Canadian expatriate (and Metafilter member) stavrosthewonderchicken has a detailed and depressing look at the impact of the mountain pine beetle in Northern British Columbia, where a perfect storm of “forest fire suppression, clearcutting (and subsequent replanting), [and] global warming” has led to the destruction of over 130,000 square kilometers of forest.