After every tornado or heavy rainfall event the usual suspects come out to announce that while they can’t blame the storm precisely on greenhouse gases, they probably/likely/maybe caused the storm to be more extreme than it otherwise would have been. After all, they reason, what else could it be? We now have an answer to that question based on a study from India, where researchers looked at the effects on rainfall from rapid urbanization in the southern part of the country. Changes to the land cover affects surface temperatures and air movements, with the end result that rainfall events do get heavier. And if it happens there, there’s a good chance it happens here too.

That said, we have noted on several occasions that Environment and Climate Change Canada cannot find evidence of increasing trends in Canadian extreme precipitation, nor have other researchers looking at the US and elsewhere. But perhaps the pace of urbanization here is not the same as South India. The important point is that when a heavy rainfall event happens and alarmists rush to blame greenhouse gases, they are jumping to a premature conclusion. Urbanization and land surface modification have the same meteorological effect, and can’t be ruled out as the cause.