Tuesday, April 29, 2014

The April 2014 Midwest Tornadoes and the Relationship to Global Warming

Just before the deadly extreme weather that tore through the Midwest at the end of April, some new research was released that indicates the intensity of tornadoes may be on the increase.

The most recent wave of extreme weather has killed at least 30 people and wounded dozens of others across the Midwest over the last 48 hours. In the last two days a spate of deadly tornadoes and powerful storms have devastated parts of Alabama, Mississippi, Tennessee, Georgia, Arkansas and Oklahoma. On Sunday a half mile wide tornado left a 70 mile long path of devastation in Little Rock, Ark., killing at least 15. The extreme weather also led to the deaths in Oklahoma and Iowa. So far, a total of seven people are confirmed dead from in Mississippi.

While it is important to note that no individual weather event can be interpreted as proof of climate change, there is evidence to suggest that tornadoes are getting stronger as the planet gets warmer. One day before the start of April's extreme weather events in the Midwest, Florida State University (FSU) published an article which cited research suggesting that tornadoes are getting worse.

According to a Saturday, April 26, 2014, FSU, publication, some preliminary research appears to corroborate the idea that Tornadoes are getting stronger. As explained by lead researcher, geography Professor James B. Elsner, “The risk of violent tornadoes appears to be increasing,”

These violent storms come just a day after the three-year anniversary of a historic outbreak of more than 60 tornadoes that killed more than 250 people across Alabama on April 27, 2011. Elsner pointed to the tornadoes three years ago saying, “The tornadoes in Oklahoma City on May 31 and the 2011 tornadoes in Joplin, Mo., and Tuscaloosa, Ala., suggest that tornadoes may be getting stronger.”

The FSU research is but the latest in a number of studies that suggest tornadoes are getting stronger. What makes this research unique is that it speaks to tornadoes specifically rather than the conditions that foster tornadoes (ie thunderstorms) as in a number of previous studies.

As reviewed in a Think Progress article, in 2011, Tom Karl, the director of the National Climatic Data Center said, "What we can say with confidence is that heavy and extreme precipitation events often associated with thunderstorms and convection are increasing and have been linked to human-induced changes in atmospheric composition."

A September 2013 study from Stanford titled, “Robust increases in severe thunderstorm environments in response to greenhouse forcing,” points to “a possible increase in the number of days supportive of tornadic storms.” In particular, the study found that sustained global warming will boost the number of days experiencing conditions that produce severe events during spring, representing “an increase of about 40 percent over the eastern U.S. by the late 21st century.”

This weather data is also supported by anecdotal evidence showing a significant increase in the amount of insurance claims associated with extreme weather in the last few years.

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