July 23, 2014

Wildfires fueled by higher-than-normal temperatures and lower-than-normal rainfall are burning an unusually large swathe of Canada’s Northwest Territories (NWT) this summer. At least 235 fires have consumed nearly 2.2 million acres (900,000 hectares), an area six times as great as the area normally affected each year during the past 25 years. Although the fires have swept across less than 1 percent of the vast NWT, the area burned equals more than the area of the states of Delaware and Rhode Island combined. More than half of the fires are burning out of control, according to the Canadian Interagency Forest Fire Center. The fires have forced hundreds of people from their home. Huge clouds of smoke and ash from the fires have also led Environment Canada, the government’s environmental protection agency, to issue poor-air-quality warnings for parts of the NWT as well as for the provinces of Alberta, Saskatchewan, and Manitoba. The smoke plume from the fires has spread thousands of miles (kilometers) south to North Dakota and South Dakota in the United States.

Daily temperature highs in Yellowknife, the capital and largest city in the NWT, have been running nearly 4 degrees Fahrenheit (2 degrees Celsius) above normal for July, while the city has received only about 2 percent of its average July rainfall. Meteorologists think that most of the fires have been sparked by lightning during “dry thunderstorms.” Such storms occur when the air below the clouds is so dry that any water falling from the clouds evaporates before it hits the ground.

Red dots mark the location of some of the large wildfires charing the Northwest Territories in Canada. Plumes of smoke from the fires have swept south and east through Canada’s prairie provinces into the United States. (Jeff Schmaltz MODIS Land Rapid Response Team, NASA GSFC)

The fires in the NTW are “in line with climate trends of more fires burning in the northern reaches of the globe,” according to Climate Central, an independant organization of climate scientists and journalists. A 2014 report by the Intergovernmental Panel on Climate Change, a United Nations committee, predicted that wildfire activity would double with every 1.8-Fahrenheit-degree (2-degree-Celsius) rise in average global temperatures. Such fires contribute to global warming by releasing soot, which darkens Arctic ice, promoting melting, and by adding more carbon dioxide to the atmosphere. Nearly all scientists think that the release of carbon dioxide and other greenhouse gasses into the atmosphere have significantly contributed to the rise in average atmospheric temperatures since the mid-1700′s. Forests in the NWT are part of the taiga, also called the boreal forest, a vast evergreen forest that circles the Northern Hemisphere. The taiga holds an estimate 30 percent of all the world’s carbon stored on land.

Additional World Book articles:

• Weather (2013) (a Back in Time article)
• Parched Earth (a Special Report)
• Weathering the Storm: Adapting to Global Warming (a Special Report)