Last month’s scorching heat wave that swept through Ontario, Quebec, and Atlantic Canada has been linked strongly to human-caused climate change, as per a groundbreaking analysis by Environment and Climate Change Canada.
From June 17 to 20, this heat wave brought exceptionally high daytime temperatures and unusually warm nights, according to the agency's observations. In New Brunswick, Saint John recorded a record-breaking 34.5°C on June 20, while Bathurst reached 37.6°C on June 19. Humidex levels soared above 40°C across the Maritimes, marking an extreme and uncomfortable period for residents.
Environment and Climate Change Canada highlighted that climate change significantly heightened the likelihood of such a heat wave occurring, estimating it to be “two to 10 times more likely” due to human activities impacting the climate.
This assessment comes as part of the agency's new rapid application tool, which compares historical climate data from before industrialization with current climate conditions. Greg Flato, a senior research scientist at Environment and Climate Change Canada, explained that this tool utilizes global climate models and computer simulations to assess the influence of greenhouse gas emissions, changes in land use, and other human activities on climate patterns.
“We compare simulations of the climate from the 1800s, before major human impacts, with simulations of today’s climate,” Flato stated. “This allows us to determine how much human-made climate change has altered the risk, probability, and likelihood of specific events such as the recent heat wave.”
The agency plans to apply this tool next to analyze the ongoing heat wave in Western Canada, with results expected in the coming weeks.