Large concurrent heat waves occur about 7 times more often than in 1980s, study finds
If this year’s sweltering summer taught us anything, it’s that temperatures are getting hotter and breaking climate records like never before.
Now, a new study says concurrent heat waves — different heat events that happen at the same time across different regions — were about seven times more frequent in the mid- to high-latitudes of the Northern Hemisphere, including the U.S., Canada, China, the U.K. and Russia, during the 2010s compared to the 1980s.
What’s more, multiple giant heat waves covering areas of about 620,000 square miles, or about four times the size of California, happened at the same time nearly every day of the warm season between May and September, on average, according to the study published last month in the Journal of Climate.
Meanwhile, heat waves are getting stronger.
The research found concurrent heat wave intensity has grown by 17%, and the geographic scope they cover increased by 46%.
Unsurprisingly, data pointed to an overall rise in global temperatures as the main driver of heat waves, researchers with Washington State University said. The trend could have devastating consequences ranging from crop failures to wildfires, and the fact concurrent heat waves are more common than ever means these threats are multiplied.
Observational data collected between 1979 and 2019 from land, water and aircraft weather stations from the European Center for Medium-Range Weather Forecasts, as well as satellite data, helped researchers understand the evolution of heat wave activity over decades. “Large” heat waves were defined as high temperature events that lasted three or more days.
“More than one heat wave occurring at the same time often has worse societal impacts than a single event,” study lead author Cassandra Rogers, a WSU post-doctoral researcher focusing on heat waves, said in a news release. “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.”
Global temperatures have risen 1.8 degrees Fahrenheit over the last century, with most of that increase occurring after 1975.
This, researchers say, means we should prepare for a world where simultaneous heat waves are much more common — if not the norm.
“As a society, we are not currently adapted to the types of climate events we’re experiencing right now,” study co-author Deepti Singh, a WSU associate professor of environmental studies, said in the release. “It’s important to understand how we can reduce our vulnerability and adapt our systems to be more resilient to these kinds of heat events that have cascading societal impacts.”
What can you do to prepare for heat waves?
Heat-related illnesses are preventable, yet can still be deadly if not treated in a timely and appropriate manner, the Centers for Disease Control and Prevention says. Extreme heat takes the lives of about 600 people in the U.S. each year.
According to the American Red Cross, “extreme heat is the most dangerous type of severe-weather event in the U.S.”
Luckily there are steps you can take to ensure your safety before and during future heat waves.
Experts say you can:
Dress your windows with reflectors, such as aluminum foil-covered cardboard, to send heat away from your home and back outside
Cover your windows with drapes or shades
Install air conditioners in your windows, if possible
Spend time with neighbors, friends or relatives who have air conditioning; the Red Cross says just a few hours away from heat “can help prevent or reduce heat-related illness.”
Visit air conditioned malls, libraries or other public spaces
You should also wear loose-fitted clothing and stay hydrated during heat wave events, experts say.
And don’t forget your sunscreen.
