Tornadoes and thunderstorms damage properties and kill people every year. According to a report, the estimated U.S. insured losses due to severe thunderstorms in the first half of 2016 were $8.5 billion. The largest U.S. impacts of tornadoes result from tornado outbreaks, sequences of tornadoes that occur in close succession.
Why Is Climate Change Responsible For Tornado Outbreak?
As per Science Publication, the researchers looked at increasing trends in the severity of tornado outbreaks around U.S. measuring severity by the number of tornadoes per outbreak. They found that these trends are increasing fastest for the most extreme outbreaks. While they saw changes in meteorological quantities that are consistent with these upward trends, the meteorological trends were not the ones expected under climate change.
Extreme meteorological environments associated with severe thunderstorms showed consistent upward trends, but the trends did not resemble those currently expected to result from global warming. Researchers looked at two factors: a measure of energy in the atmosphere called convective available potential energy (CAPE), and a measure of vertical wind shear, called storm relative helicity.
The Research Study
According to TechTimes, the researchers are offering new insight into the trends in environmental conditions that encourage thunderstorms and tornadoes, the study looks at the convective available potential energy, or CAPE, and storm relative helicity, a measure of vertical wind shear. With greenhouse gases trapping more energy and heat in the atmosphere air will start holding more water and that opens the scope for extreme storms.
“This study raises new questions about what climate change will do to severe thunderstorms and what is responsible for recent trends,” says the team led by Michael Tippett, associate professor of applied physics and applied mathematics at Columbia Engineering. Tippet is also a member of the Data Science Institute and the Columbia Initiative on Extreme Weather and Climate.
"The fact that we don’t see the presently understood meteorological signature of global warming in changing outbreak statistics leaves two possibilities: Either the recent increases are not due to a warming climate, or a warming climate has implications for tornado activity that we don’t understand. This is an unexpected finding.”
The study found that the meteorological trends were not due to increasing CAPE but instead due to trends in storm relative helicity, which has not been projected to increase under climate change. As per Science Daily, better understanding of how climate affects tornado activity can help to predict tornado activity in the short-term, a month, or even a year in advance.