In discussing increased extreme rain events, Daniel Swain dropped some knowledge on me that was new.
It’s generally known that for each degree centigrade of warming, globally, atmospheric water vapor increases by about 7 percent – which is already a lot – equivalent to having another Lake Superior sloshing around in the atmosphere.
But there’s more to it.
When storms occur, and there’s more heat energy around, which is gasoline for storms – the rain in extreme events can be double, or triple, that 7 percent.
Meaning rain events that are 14%, or 21% larger than what might have occurred with the same conditions in decades past.
Good context for the rash of extreme floods we have seen, and will continue to see.