Heat wave in June in Quebec | More likely due to climate change

The heat wave that hit Quebec in mid-June bore the hallmarks of climate change, Environment Canada says. With its new rapid attribution system, the government agency says this extreme weather event was two to ten times more likely due to human influence on the climate.

A rare episode in June

Eastern Ontario, southern and northern Quebec, and the Atlantic provinces experienced an episode of intense heat between June 17 and 20. More than 200 day and night temperature records were set during this period, reports Simon Legault, a meteorologist with Environment Canada. In Montreal, the mercury reached 34 degrees. “It’s rare to have such hot and humid conditions so early in June,” says Mr. Legault. A three-day sequence with temperatures of at least 32 degrees before June 20 had only been observed twice before, in 1919 and 1978.

A new rapid allocation system

According to Environment Canada, this heat wave has been made more likely by climate change. It’s two to 10 times more likely, according to the federal agency’s new rapid attribution system. The grid has seven levels that rank the influence of climate change on an extreme weather event in order of importance. The June heat wave ranked sixth, with the seventh level grouping events made at least 10 times more likely by climate change. “Attribution studies are done with the help of computer simulations of the global climate,” explains Greg Flato, director of climate research at Environment Canada.

Helping the public better understand climate change

With scientific advances, attribution studies are becoming more common, says Greg Flato. Environment Canada has been working for a few years to set up a rapid attribution system. It has been officially operational since last April, and the analysis of the June heat wave is the first one whose results have been released by the agency. “We want to provide information to people so that they can better understand how humans cause climate change and how it has an effect on these climate extremes. By understanding the role of these different climate changes, we can better prepare, better adapt to these changes,” adds Mr. Flato.

An increasingly robust science

The international group of scientists World Weather Attribution (WWA) is one of the pioneers of such studies. Since its founding in 2014, the NGO has conducted more than 50 attribution studies of extreme weather events in different regions of the world. Last May, WWA reported in a study that climate change had added an average of 26 days of extreme heat over the previous 12 months globally. More recently, WWA scientists determined that climate change made the deadly heat wave that hit Mexico last June 30 more likely.

Temperature records pile up

June 2024 became the 13th^e consecutive month to set a global average temperature record. During that 13-month period, the average temperature was 1.64 degrees above the pre-industrial average. Since 1850, the planet has already warmed by about 1.2 degrees, and scientists estimate that the 1.5-degree threshold has a 50-50 chance of being reached on average between 2030 and 2035. Ocean warming is another concern for the scientific community, particularly in the North Atlantic, where water temperatures continue to rise. The National Oceanic and Atmospheric Administration (NOAA) is predicting a more intense hurricane season than usual due to warmer waters in the Atlantic.