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Richard Gleeson
Northern News Services
One of the elements of the Northern environment that will be most harmed by climate change will be our forests.
 Vehicles are the leading source of carbon dioxide, the most predominant greenhouse gas. In the NWT in winter, emissions rise as vehicles are left idling to keep warm. - Merle Robillard/NNSL photo |
"The magnitude and rate of change 50 years from now is still in our control," said Environment Canada climate change adviser Henry Hengeveld.
"But what happens between now and then, in many respects, is already in the works. So we better learn to also anticipate those changes and prepare for them."
The warming is caused by exhaust gases that gather in the atmosphere, trapping more of the sun's warmth. The greenhouse gases have the same effect on the planet as wearing two parkas would have on a person.
Hengeveld said predictions on the rate of global warming range from 1.4 degrees per century to 5.8 degrees. Double that for Canada, he said, because large land masses warm faster than oceans and the North is warming faster than the South.
"Even at the low end, its unprecedented in human history," Hengeveld said. "At the higher end you're talking about a change similar to that between the last ice age and today, except this takes place in a century rather than the 5,000 years the de-glaciation took."
Troubled trees
Warming will mean big changes for plants and animals. Much of the attention so far has focused on the plight of animals, particularly polar bears.
Climate change is expected to have an even greater impact on plant life, particularly the trees so many animals rely on for food and shelter.
"The process of change will involve insect infestation, dieback and fire," Hengeveld said of tree populations.
Older forests, which are more thickly wooded and contain more deadfall, are the most likely candidates for fires. Old-growth forests are also prime winter habitat for caribou.
"If the climate change people have it right, then caribou habitat will disappear at a rate faster than it will be replaced," said Rick Lanoville, manager of forest science services for the Department of Resources, Wildlife and Economic Development.
When an old-growth forest burns, one of the first things to go are lichens, which caribou rely on for in winter. Lichens take years to grow back.
In an attempt to manage the fire hazard that climate change presents, the territorial government is identifying areas most vulnerable to large fires.
Natural cycles
Fires are a natural part of a forest's life cycle. With no material to fuel a fire, recently burned areas act as a firebreak to control the spread of new fires.
"What we're trying to do now is identify which areas would support large fires. We would then have to consult with wildlife management and local people to see what the best strategy would be to deal with it."
As the climate warms, the North will become home to new species of insect pests migrating from the south that will pose new threats to the forest.
RWED forest ecologist Bob Decker said that has already happened once, when forest tent caterpillars started attacking trees in the Fort Liard area in 1995. It was the first recorded infestation of the caterpillars in the Northwest Territories.
Warming also allows existing pests to thrive.
British Columbia has had infestations of mountain pine beetles, but nothing like the one it is now dealing with. Successive warm winters have allowed the beetles to spread across 600,000 hectares of forest.
Similarly, the spruce budworm is thriving in the NWT. Decker said the pest can now be found from Fort Smith "more or less continuously" to Tulita. He said there is no solid link between the increasing damage caused by the pest and climate change.
"We're talking about hundreds of thousands of hectares that are impacted," Decker said.
Warming sources
Carbon dioxide emissions make up about 76 per cent of greenhouse gas emissions
Carbon dioxide sources
