The powerful storms that cause extreme weather conditions, such as floods in Europe and North America, with the potential to cause social and economic havoc, could multiply by three by the end of the 21st century due to climate change.
New pioneering research, led by Dr. Matt Hawcroft of the University of Exeter, has shown new and detailed information on projections of the frequency of extratropical cyclones.
Research shows that, unless there is a significant reduction in greenhouse gas emissions, there will be a marked increase in their frequency in the large swaths of the northern hemisphere.
Crucially, the impact on local communities could be severe, with more intense and extreme storms leading to larger floods on a large scale, similar to those experienced in Somerset in 2013/14, Cumbria in 2015 and Gloucestershire in 2007.
The research is published in the magazine. Environmental research letters on Tuesday, November 27, 2018.
Dr. Hawcroft, a researcher in the Mathematics Department of Exeter, said: "Extreme rainfall is expected to increase in intensity and frequency in a warmer climate." In this paper, we have attributed those changes to the events that bring much of the our large scale rain and floods This additional information, on the dynamic nature of the changes, is important as it provides clear information about the nature and impact of changes in rainfall that can be used, for example, in policy formulation and adaptation planning. "
Extratropical cyclones, directed by the jet stream, play a key role in daily climate variability in much of North America and Europe. They are characterized by areas of low atmospheric pressure in the center of the storm, with air sucked cyclonically (counterclockwise) around the low pressure.
This leads to hot air being drawn from the south and cold air from the north. In fronts of cold and warm air, fronts are formed that can cause heavy rain. The most extreme storms are responsible for large-scale large-scale floods in North America and Europe.
A key datum for policymakers and governments seeking to mitigate these extreme weather conditions is the ability to project where and how often these storms can occur in the future. However, the projections of current climate models are affected by huge uncertainties.
In this new study, the researchers analyzed the behavior of current and future storms using state-of-the-art modeling and tracking techniques. By addressing the analysis in a "storm-centered" framework, the team was able to assess changes in the frequency and intensity of these extratropical cyclones with greater consistency than previous studies have suggested.
It is important to note that the research team was able to demonstrate that the models project that there will be a triple increase in the number of the most precipitating extratropical cyclones in Europe and North America by the end of the century.
Dr. Hawcroft added: "Due to the complexity of the circulation response to warming, there is a lot of uncertainty in the regional patterns of climate change, given this uncertainty, it is important to be able to extract clear information where available. From these complexities, we can still provide large and consistent change projections in these highly impactful events. "
What is causing more extreme rainfall in the Northeast?
The significant increase in extreme precipitation expected in Europe and North America from extratropical cyclones is published in Environmental research letters.