The United States have been affected by a number of killer tornadoes within the last few months. With 337 fatalities in the South, this is another national crisis. Given the frequency and intensity of the previous storms, more than any that I remember happening in such a short amount of time, I was interested to see what scientists had to say about climate change and tornadoes. The article states:
As far as climate change and tornadoes go, there’s no clear expectation. The two most important large-scale variables severe thunderstorms are convective available potential energy (CAPE-a thermodynamic measure) and the vertical wind shear (magnitude of the difference between the horizontal winds near the surface and aloft, say, near 6 km above the ground.
There are important caveats, however. First, it is possible that initiation of thunderstorms won’t follow that trend (we can’t model it well at this point) and that the atmosphere won’t ‘take advantage’ of the favorable conditions at the same rate as it does now. For tornadoes, a second important issue is that tornadoes are much more dependent on wind shear that non-tornadic severe storms. As a result, the increased thermo/decreased shear implies that the fraction of storms that are tornadic could decrease. How that compares to a increase in the base rate of severe storms is unknown, but does imply tornado frequency is less likely to increase than non-severe storms.
You’ll see that there are a lot of ‘unknowns’ in this article, but I thought it was an interesting read and gave me a better understanding of how and why tornadoes occur. Time will tell if there is a direct correlation with climate change and tornadoes!