Sierra Club of Canada Fact Sheet - 1996

Forest Fires & Climate Change

Forest fires and climate change: What's the connection?

Wildfire is a natural part of the life cycle of the boreal forest. Boreal forests are susceptible to fire because litter from black and white spruce, balsam fir and jack pine does not easily decompose. As a result, it builds up on the forest floor and becomes extremely flammable. This build-up of litter also locks in nutrients. If nothing is done by forest managers to suppress fire, wildfires sweep through boreal forests every 50 to 200 years (sooner in the south, later in the north). By burning litter, fire releases mineral nutrients and establishes the right conditions for seeds to germinate. Fire also determines species distribution in the forest, age-class and carbon storage. (1 )

Climate change could drive the natural forest fire rhythm out of control. Climate scientists predict that pouring billions of tonnes of greenhouse gases, like carbon dioxide (CO2), into the atmosphere will increase global temperatures, change precipitation and atmospheric and ocean circulation patterns. (2 ) These changes are expected to lead to drier conditions in the boreal forest, with some models predicting a 40 - 50 per cent increase in the area burned each year in Canada, as well as more frequent fires of higher intensity in the forest-tundra. (3 )

These changes may already be upon us.

Since 1984, an average of 1.7 million hectares of forest have burned in Canada because of wildfires. But in 1994, 6.5 million hectares burned; only 1989 was higher at 7.3 million hectares. The summer of 1995 almost tied 1989 - nearly seven million hectares burned because of wildfires.

A recent study (4) that looked at fires and pest outbreaks in Canadian forests found a two-fold increase in natural disturbances since 1970.

The carbon cycle

All living plants, including trees, grow by absorbing carbon dioxide from the atmosphere through a chemical process called photosynthesis. (5 ) When trees and plants decompose or burn, they release this carbon dioxide back into the atmosphere. The carbon stored in living things (biomass) is called a reservoir because it remains stored only for the life of the plant or tree. Under normal conditions, the carbon absorbed by living things is balanced by that released from decomposition and burning.

Clearing land for urban development and agriculture now adds more carbon dioxide to the atmosphere each year than is being absorbed by living plants - between 1 - 2 billion tonnes of carbon a year more, according to the Intergovernmental Panel on Climate Change (IPCC). Most of these emissions are thought to come from tropical forests, although the northern boreal forest may already be increasing its contribution.

Boreal forests cover approximately 17 per cent of the world's land surface, mostly circling the polar areas of North America and Eurasia. The boreal forest contains about 65 million tonnes of carbon in trunks, branches and leaves, and 270 billion tonnes of carbon in its soils and decaying matter. The boreal region absorbs about 0.4 to 0.6 billion tonnes of carbon each year (Apps et al., 1993). Up to now, the northern forest's absorption of carbon dioxide has been thought to offset the increases in emissions coming from cutting down and burning tropical forests. That assumption certainly no longer holds in Canada where fire and pest outbreaks since 1970 have turned the Canadian forest from a sink to a source of carbon.

Declining forests will make climate change worse

More forest fires and pest outbreaks could shift large amounts of the carbon stored in living things to the atmosphere where it could make climate change worse. In fact, some models project up to two billion extra tonnes of carbon ending up in the atmosphere as a result of forest decline.

Boreal forests will disappear

It takes decades to centuries for the boreal forest to grow back after a fire. But with changing climatic conditions (temperature zones and precipitation patterns will no longer support the growth of the boreal forest), the expectation is that the boreal forest will NOT return in Canada. Instead, it will be replaced over time with grassland throughout the Prairies and with temperate deciduous forest throughout eastern Canada. Only northern Quebec, Labrador, the Yukon and Northwest Territories would retain remnants of the boreal forest.

Canada's forest sector will be hard hit

In 1993, according to Forestry Canada, the value of Canadian forest product exports was $26.7 billion.

Of the 417.6 million hectares of forests in Canada, 56 per cent is currently managed for timber purposes. Almost all of Canada's forests are categorized as boreal.

Forest fires are also expensive to control. Forest fire control has cost more than $210 million each year since 1988 (not including 1995's record) - almost all of which is paid for by taxpayers.

No one is defending the interests of the forest or forest workers

The federal Minister of Natural Resources is responsible for forests and their biggest threat - the oil and gas sector. To date, only the interests of the oil and gas sector are being protected, and it's at the expense of the forest sector.

If you care about Canada's forests, or your job, take action. Make climate change an issue your community cares about. Contact the Sierra Club to arrange for a presentation on climate change. Write, phone or fax your provincial and federal minister responsible for forests, and tell them you want action. Send them this fact sheet. Tell your premier and the prime minister it's time Canada improved energy efficiency and used more renewable energy. Tell governments Canada must reduce its carbon dioxide emissions by 20 per cent by 2005.


1 The Impacts of climate change on forest ecosystems, Intergovernmental Panel on Climate Change, 1995 Second Assessment.

2 More than 7 billion tonnes of carbon was released into the atmosphere in 1994 from burning oil, coal and natural gas and from deforestation. Other greenhouse gases include methane, most of which comes from natural gas, but also from livestock, manure and landfills; nitrous oxide is released from cars, fertilizers and nylon production. Coolants in air conditioners and refrigerators also are very powerful greenhouse gases. Carbon dioxide and other greenhouse gases trap heat which in turn raises temperatures and changes climate systems like atmospheric and ocean ci culation and precipitation patterns. Scientists are predicting temperature increases of between 1 - 3.5oC by 2100. For more information, read Sierra Club of Canada's "Climate Change" (subtitled: "People are changing the world's climate system").

3 Flannigan and van Wagner (1991); Stocks, 1993; FIRESCAN Science Team, 1994; Fosberg et al., 1994.

4 Retrospective assessment of carbon flows in Canadian boreal forests, Werner A. Kurz and Michael J. Apps, 1995.

5 The sun's light energy is used by chlorophyll to capture carbon dioxide and water which is then converted to sugars, and then into carbohydrates and cellulose to make the plant's body.


Copyright 1996 Sierra Club of Canada