Increased number of “blocking events” to create deadly weather systems

December 3, 2019

Manmade climate change will increase the number of stalled weather patterns and create more deadly extreme weather events, according to researchers from the National Science Foundation and Rice University.

The recent study found that the frequency of atmospheric blocking events – middle-latitude, high-pressure weather systems that remain stagnant for days or weeks – will increase by approximately 17% thanks to climate change.

Heat waves are one common symptom of stagnant weather systems, but blocking vents can also cause extreme cold, droughts, and flooding.

The National Science Foundation attributes some of the 21st century’s deadliest extreme weather to blocking events, such as heat waves in France in 2003 and Russia in 2010, which resulted in human deaths.
In addition to evaluating the frequency of these systems, the scientists also looked at the prospective size of the blocking events. They found that the events will get larger as time goes on, meaning they will have more influence on weather patterns and create bigger impacts for humans.

"Studies in the past have looked at whether you get more or fewer blocking events with climate change," said study scientist Pedram Hassanzadeh in a press release. "The question nobody had asked is whether the size of these events will change. And the size is very important. If the high-pressure system becomes bigger, you are going to get bigger heat waves that affect more people, and you are likely going to get stronger heat waves."

The study’s findings were published in Geophysical Research Letters.

Increased number of “blocking events” to create deadly weather systems