Heatwaves are 7 times more likely now than they were in the 80s

Heatwaves are seven times more frequent than in the 1980s, according to researchers at Washington State University. 

Using climate data from 1979 to 2019, the researchers found that the number of heatwaves occurring simultaneously in the mid-to-high-latitudes of the Northern Hemisphere was seven times greater. 

On average, there were concurrent heatwaves on 143 days each year of the 2010s.

The concurrent heat events also grew hotter and larger; their intensity rose by 17% and their geographic extent increased by 46%. 

Heatwaves can cause disasters from crop failures to wildfires and concurrent heatwaves can multiply those threats, exhausting the ability of countries to provide aid.

Cassandra Rogers, lead author of the study said: ‘More than one heatwave occurring at the same time often has worse societal impacts than a single event.

‘If certain regions are dependent on one another, for instance for agriculture or trade, and they’re both undergoing stresses at the same time, they may not be able to respond to both events.’

Using these observational data, the researchers found that the primary driver of the heatwaves was the overall rise in global mean temperature due to climate change.

The world has warmed 1 degree Celsius over the last century with the vast majority of the rise, two-thirds, occurring since 1975. 

‘As a society, we are not currently adapted to the types of climate events we’re experiencing right now,’ said co-author Deepti Singh, WSU associate professor in the School of the Environment.

‘It’s important to understand how we can reduce our vulnerability and adapt our systems to be more resilient to these kind of heat events that have cascading societal impacts.’