How Is Climate Change Affecting Wildfires?

The wildfires burning across Canada have become a global story. As of early June, more than 10 million acres have burned, and it could be Canada's worst wildfire season ever. The fires have led people to wonder, "does climate change cause wildfires?

While it's uncertain whether climate change has directly caused these particular fires, scientists do believe that, overall, we are seeing more wildfires every year because of a warming planet.

The increase in hot, dry weather means drier forests, grass, and undergrowth, ideal fodder for fire. Forest fires and wildfires around the world last longer and burn with more intensity than previously recorded. The area of land burned by wildfires has surged in the past 30 years across North America.

The Intergovernmental Panel on Climate Change (IPCC) reports that a 1-degree Celsius rise (1.8 degrees Fahrenheit) in average temperatures has increased the length of the fire season in northern Asia by 30 percent. In Canada, we increasingly hear people refer to summer as “fire season.”

Here we look closer at the consequences of wildfires, climate change, and the ways it leads to fires blazing out of control and what people can do to prevent them.

The costs of wildfires and climate change

These fires have serious consequences, not only for the environment and our health (air quality suffers), but also for infrastructure. Major wildfires in Australia, in 2020 displaced 3 billion animals, while intense fires devastated areas from California to Greece to British Columbia. The 2007 fires across the state of California destroyed 1,500 homes. As the IPCC expected, forest fires and wildfires have increased while temperatures continue to rise and some areas experience reduced rainfall.

The first major economic hit to Canada from the climate crisis was the dramatic pine beetle outbreak in British Columbia. The pine beetle is an insect that has a special talent for turning a forest into firewood. Previously, pine beetles didn’t survive the winter. Due to warmer winters, the insect numbers hit catastrophic levels and wiped out an area of forest twice the size of Sweden.

All that standing dead wood combined with rising temperatures to create a perfect storm for wildfires. Fires in 2017 and 2021 made breathing unsafe over a large area due to smoke, and very dramatically on July 1, 2021, in 15 minutes, burned the entire town of Lytton to the ground before the fire truck could get out of the station.

In fact, because of both fire and increased insect damage, forests in Canada ceased to be a net sink (refer to Chapter 2) for carbon in the mid-1970s. Canada’s forests still hold millions of tons of carbon, but on an annual basis, these forests now give off more carbon than they suck in. Adding to this vicious cycle, forest fires pump carbon dioxide into the air when the wood burns and releases the gas.

Recognizing how they start and how to prevent them

When trees are tinder dry, it doesn’t take much to start a wildfire. Even dry grass can cause devastating fires as happened near Denver, Colorado, in late 2021. Successive years of drought create fuel for fires. When local practices don’t remove that fuel, the chances of fires increase. Communities and larger governments need to promote fire smarting to remove the fuel on the forest floor. Controlled burning as was practiced by indigenous people can help keep wildfires from burning too long or too hot and out of control.

When conditions are perfect for fires, it doesn’t take much to cause a disaster. A carelessly tossed cigarette but, a spark from heavy equipment, and quite commonly a lightning strike can cause a massive fire.

In the summer of 2021, with more than 1,600 significant forest fires across British Columbia, we learned a new word pyrocumulonimbus — clouds that are formed by fire and rise very high into the atmosphere. Often they carry burning materials from the original fire that can fall to earth far and ignite new fires.