The return of tornado season with a vengeance has people asking again about a possible link to climate change. At the same time, tantalizing new preliminary research finds “some evidence to suggest that tornadoes are, in fact, getting stronger.” I talked to the lead scientist behind that research. Tom Karl, the director of the National Climatic Data Center, explained in a 2011 email: 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. Insured losses due to thunderstorms and tornadoes in the U.S. in 2013 dollars. Data and image from Property Claims Service, Munich Re . And a September 2013 study from Stanford, “ Robust increases in severe thunderstorm environments in response to greenhouse forcing ,” points to “a possible increase in the number of days supportive of […]