Massive wildfires in Canada helped keep the world cooler in 2023

2023 witnessed the highest temperatures on record, but a recent study suggests that it could have been even hotter if not for the cooling effect of smoke from massive wildfires in Canada. According to a climate model, the entire northern hemisphere would have been nearly 1°C warmer on average during the summer months without the presence of the wildfire smoke. This phenomenon also contributed to the driest August ever recorded in India.

Researcher Iulian-Alin Rosu from the Technical University of Crete in Greece revealed that the scale of the wildfires in Canada was unprecedented, with emissions estimated to be five to six times higher than any previous wildfire season in the country. While the carbon dioxide released from the fires continues to have a warming effect, in 2023, the cooling impact of the smoke outweighed this warming effect by blocking sunlight.

Using climate model simulations, Rosu and his team found that the smoke caused local cooling of up to 5.4°C in certain parts of Canada and led to a 0.9°C cooling effect on the entire northern hemisphere between May and September. Surprisingly, despite setting heat records in western regions of Canada, the smoke predominantly blew eastwards, resulting in a significant cooling effect in that area of the country.

The repercussions of the wildfires extended beyond Canada, affecting weather patterns in Asia. The emissions altered wind patterns over the region, weakening the monsoon and causing reduced rainfall in India, mirroring the model’s predictions.

While the cooling effect was substantial during the summer months, it was short-lived. By November and December, the impact had largely dissipated. Furthermore, the record for the hottest year set in 2023 was quickly surpassed by even higher temperatures in 2024.