“Record-shattering” heatwaves will be much more likely in the future

Today’s fast pace of global warming virtually guarantees more extreme temperature records around the world, according to a new study. Much of the US, Europe, and Asia will experience more deadly heatwaves in the coming decades, just like the one recently experienced in the Pacific Northwest, with shattered temperature records. In other words, we’re just getting started with the heatwaves.

Heatwaves are not only a nuisance but can also be very dangerous, leading to illness and even death, especially among the most vulnerable (like older adults and the very young). Because of climate change, they are occurring more frequently, are getting more intense, and are lasting longer than they did in the past. 

“The main message is that we need to prepare for more record heat events in the coming decades that shatter previous record temperatures by large margins,” Erich Fischer, lead author, told Axios. “Because we are in a period of very rapid warming, we need to prepare for more heat events that shatter previous records by large margins.”

The researchers argued that climate change is still not much appreciated as a driver of extreme heat, despite the growing pace of emissions guaranteeing more extreme temperature records in the coming decades. Global average temperatures have already grown 1ºC compared to pre-industrial times, a trend set to continue in the future decades. However, this doesn’t mean that the entire globe will uniformly be hotter by one degree — the shifts are irregular and often more extreme in some parts of the world.

Heating up

Fisher and a team at ETH Zurich used computer models and records of past weather events to examine how the chances for record heat waves have been shifting and will continue to change as global warming continues. They focused on the occurrence of week-long heatwaves, such as the one that happened in the Pacific Northwest. 

Under a high-emissions scenario, heatwaves that break previous records by roughly 5ºC would become two to seven times more likely in the next three decades and three to 21 times more likely from 2051 to 2080, according to the study’s findings. Such extreme heatwaves would be impossible without global warming, the researchers said.

“This study underscores something that has been apparent in the record weather extremes we’ve seen this summer: dangerous climate change is here, and it’s now simply a matter of how dangerous we are willing to let it get,” climate expert Michael Mann from Pennsylvania State University, not part of the new research, told The Guardian. 

In a recent study, Mann and a global team of researchers concluded that the occurrence of a heatwave with maximum daily temperatures as observed in some areas of the US and Canada was “virtually impossible” without climate change. The temperatures were so extreme that they lie far outside the range of historically observed temperatures. 

Our best chance of limiting the effects of climate change is by reducing our greenhouse gas emissions. While we’re making some progress on this front, it’s far too underwhelming to avoid problems like this. Keeping the planet within 2ºC of warming will require a quick decarbonization of our economy and a transition to renewable energy.

The study was published in the journal Nature. 

28 July 2021

ZME SCIENCE