text:  But it also tends to weaken wind shear, at least in a global sense across the planet, which would reduce the chances of tornadoes. We have noticed in the last 10 or 20 years that we seem to have these bigger gaps where the United States gets very quiet and then periods with a lot of action. And this year, for instance, has been extremely active, the second most active year after 2011. But we've had a lot of very quiet tornado years as well. So we are noticing