Global warming has made extreme weather conditions behind the raging fire season in eastern Canada this year at least seven times more likely, according to a study released Tuesday, August 22 by a network of scientists specializing in fires. ‘analyzes. World Weather Attribution (WWA) researchers have determined that climate change, caused by human activity, has increased the likelihood of high temperatures and low humidity levels in particular, which have played a major role in the spread of the blaze.
Canada is experiencing the most devastating fire season in its history this year. Over 1,000 fires are active from east to west at this time. More than 15 million hectares have already burned in total in the country, an area larger than Greece. This is already more than double the previous record for a full fire season, which is still far from over this year. About 200,000 residents had to be evacuated, and four people died.
“Rising temperatures are creating powder keg-like conditions in forests across Canada and around the world,” said one of the researchers involved in the work, British climatologist Friederike Otto, in a statement. “Until we stop burning fossil fuels, the number of forest fires will continue to rise.”
The researchers studied a measure called the “forest-weather index,” which combines temperature, wind speed, humidity, and precipitation, to estimate the risk of forest fires. They then isolated the seven-day period during which the weather conditions were most favorable to fires, between May and July. According to their analysis, these extreme conditions have been made twice as likely to occur due to climate change. The latter also made these conditions 20% more intense, according to the study.
Secondly, the researchers wanted to assess the severity of the weather conditions over the entire past season. For this, they took into account the daily values derived from the same index, from January to July. The likelihood of such fire-favorable conditions occurring over that time has been increased sevenfold by global warming, they determined. They have also been made 50% more intense.
The May to June period was the warmest on record in Canada since records began in 1940. High temperatures caused the snow to melt rapidly in May, allowing fires to develop early.
The consequences of the fires in Quebec were felt as far away as New York and Washington, in the United States, where their smoke darkened the sky in June, with levels of fine particle pollution qualified as dangerous for health. Schools had to be temporarily closed and outdoor events cancelled.
Fires of such magnitude also aggravate climate change, as they themselves release greenhouse gases. Most Canadian fires occur in the boreal forest, which releases more carbon than other ecosystems when it burns. In total, the country’s fires this year have generated the equivalent of more than a billion tonnes of CO2, unprecedented.
WWA researchers also point to the consequences on isolated populations, the logging industry, and ecosystems. “The term ‘unprecedented’ does not do justice to the severity of the wildfires that have ravaged Canada this year,” said Yan Boulanger. “From a scientific point of view, the doubling of the previous record for area burned is nothing short of amazing.”