A significant heatwave is expected throughout much of Canada next week bringing temperatures more than 10°C above normal. This heatwave is notable for several reasons—notably that it is occurring so early in the season and during a year in which we are expecting an El Niño shift.

El Niño periods are associated with global heating, meaning that the planet is likely to see a new highest temperature later this year or in 2024 as El Niño continues to develop. Professor Adam Scaife of the Met Office highlights that climate change is increasing the power of El Niño events: “You put those two things together, and we are likely to see unprecedented heatwaves during the next El Nino.”

Whilst the May heatwave is unlikely to set new national records, it’s a primer for what could be a very hot summer. Extreme heat sets the stage for hospitalisations, wildfires and crop failures. British Columbia is still reeling from the effects of the 2021 Western North American heatwave, which was the deadliest weather event in Canada during which nearly 1,500 people died . Damage to crops led to an increase in food prices globally, and a new national record was set in the small town of Lytton, BC, which saw the mercury climb to 49.6°C (121.3°F). The following day, 90% of the town was decimated in a wildfire that was fuelled by the hot, dry conditions. The town is still in the process of achieving permissions to rebuild.

This record—the highest in any part of the world north of 45°N–was notably set in the midst of La Niña, a period of global cooling.

Image: Climate Reanalyzer, projection for 03 May, 2023