The CC0 Public Domain is a public domain.
A study led by Washington State University found that there were multiple large heatwaves the size of Mongolia at the same time every day during the warm seasons of the 2010s across the Northern Hemisphere.
In the 2010s, the number of heatwaves occurring simultaneously in the mid- to high-latitudes of the Northern Hemisphere was seven times greater than in the 1980s. There were concurrent heatwaves on almost every day of the warm months of May through September.
The heat events grew larger and hotter, with their intensity rising by 17% and their geographic extent increasing by 42%.
A single event can have worse societal impacts than more than one, according to a study by a post-doctoral researcher. If certain regions are dependent on one another, they may not be able to respond to both events.
Disasters can be caused by heat waves. The authors pointed out that the ability of countries to provide mutual aid in crises was exhausted during the multiple wildfires in the U.S., Canada and Australia associated with the 2019 and 2020 heatwaves. A previous study found that there was a 4% drop in global crop production.
The study defined large heatwaves as high temperature events lasting three days or more and covering at least 1.6 million square kilometers, which is roughly equivalent to the size of Iran or Mongolia.
The European Center for Medium-Range Weather Forecasts blends vast amounts of observational data from weather stations on land, water buoys and aircraft as well as data from satellites with weather forecasting models. The study focused on this time period because of the complete estimates of hourly data for various climate variables from 1979 that are provided by the company.
The researchers found that the main driver of the heatwaves was the rise in global mean temperature due to climate change. The world has warmed 1 degree Celsius over the last century with the majority of the rise occurring since 1975. Increased occurrence of two hemisphere-wide circulation patterns made certain areas more vulnerable to concurrent heatwaves, including eastern North America, eastern and northern Europe, East Asia and eastern Siberia.
The continued rise in temperature means the world should prepare for more concurrent heatwaves, and the study adds more evidence for the need to curb greenhouse gas emissions and mitigate climate change.
"As a society, we are not currently adapted to the types of climate events we're experiencing right now," said co-author Deepti Singh, an 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 heat events that have cascading societal impacts.
The authors on the study include Rogers and Singh, as well as Kai, Sarah, and Paul.
The increase in large heatwaves driven by warming and changing atmospheric circulations has been documented by the authors. The JCLI-D-21-0200.1 can be found in the book.
Journal of Climate.
Concurrent heatwaves are seven times more frequent than the 1980s.
The document is copyrighted. Any fair dealing for the purpose of private study or research cannot be reproduced without written permission. The content is not intended to be used for anything other than information purposes.
