Global Warming to Increase US Thunderstorms and Tornadoes, Says Study

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Written By:Emma Websdale

Continued global warming likely contributing to creating atmospheric conditions will increase the frequency of deadly thunderstorms and tornadoes across the United States, a new study suggests. 

The study, led by Noah Diffenbaugh of Stanford University is one of the first to have found a link between climate change and severe storms. By conducting a series of comprehensive computer modeling, the scientists analyzed the effects of global warming on two major conditions responsible for thunderstorm formation – Convective available potential energy (CAPE) and wind shear.

The results, published this week in the journal Proceedings of the National Academy of Sciences, has found that springtime thunderstorms could increase by as much as 40% over the eastern U.S by the end of the century.

For severe thunderstorms to arise CAPE must interact with strong vertical wind shear. Some previous research suggested that although global warming will increase CAPE, it would also decrease wind shear – preventing the interaction between the two. However, results from the new Stanford University study discovered a pattern that has been missed in previous modelling.

The new modelling suggests that when CAPE is high, vertical wind shear is also likely to be high, resulting in global warming actually increasing the total frequency of occurrence of severe thunderstorms.

“We’re seeing that global warming produces more days with high CAPE and sufficient shear to form severe thunderstorms”, said Noah F Diffenbaugh, one of the authors.

“The net effect is that there will be more days overall with both high CAPE and high shear.”

The report raises concerns as weather conditions, including severe thunderstones are one of the primary causes of major economic losses in the United States. In 2012, seven of the country’s severe thunderstorms and tornadoes resulted in $11 billion costs in damage.