A series of climate model simulations revealed that Canada’s massive wildfires in 2023 had a surprising cooling effect on the global temperature, keeping the northern hemisphere nearly 1°C cooler than it might have been without their smoke.
Massive wildfires in Canada had a surprising effect on the global temperature in 2023, helping to keep the world cooler than it might have been without their smoke. A climate model suggests that without the cooling effect of Canadian wildfires, the entire northern hemisphere would have been nearly 1°C warmer during its summer.
The emissions from these fires were around five or six times higher than those during any previously recorded wildfire season in Canada, estimates Iulian-Alin Rosu at the Technical University of Crete. However, the carbon dioxide from these fires is having an ongoing warming effect, which was outweighed by the cooling effect of smoke blocking sunlight.
Wildfires in Canada have been a recurring issue, with the country experiencing some of its worst fires on record.
According to Natural Resources Canada, between 2000 and 2019, an average of over 8,000 wildfires occurred annually.
The majority of these fires are caused by lightning strikes, while human activity is also a significant contributor.
In recent years, climate change has exacerbated the issue, with warmer temperatures and changing precipitation patterns creating ideal conditions for wildfires to spread.
In a series of climate model simulations, Rosu and his colleagues ran scenarios with and without Canadian wildfire emissions. The results showed that between May and September, the smoke caused local cooling of as much as 5.4°C (9.7°F) in small parts of Canada, and that the northern hemisphere as a whole was 0.9°C (1.6°F) cooler.
This may seem surprising given that parts of Canada saw record temperatures during that summer. However, the heat records were mostly in western regions, whereas the smoke blew east and had the biggest cooling effect on that side of the country.
The impacts of the wildfires weren’t limited to Canada. The model suggested changes in winds over Asia that weakened the monsoon and led to less rainfall in India – a phenomenon that was observed in reality. “The precipitation anomaly that is seen in the data is really, really close to what we see in our model,” says Rosu.
India is a vast and diverse country, spanning multiple climate zones.
Its climate varies from tropical to temperate and arctic conditions, depending on the region.
The Himalayas in the north create a rain shadow effect, resulting in dry conditions in areas like 'Rajasthan'.
Monsoon rains bring significant precipitation to the west coast during summer months.
Temperature extremes range from -20°C in winter to 50°C in summer, with humidity levels varying greatly between regions.
However, the cooling effect didn’t last long. By November and December, there wasn’t much of an effect left. The record-breaking year for hottest temperatures set in 2023 also didn’t last – 2024 turned out to be even hotter.
- newscientist.com | Massive wildfires in Canada helped keep the world cooler in 2023
