I’d guess that WWII’s worldwide firebombing campaigns vs WWI’s use of large clouds of aerosolized gaseous weaponry, but that’s just a guess.
Firebombing heats things up, and kills vegetation that keeps things cool. Aerosols and other particulates temporarily reflect extra sunlight back to space.
And there’s also a temporary cooling during WWI.
I’d guess that WWII’s worldwide firebombing campaigns vs WWI’s use of large clouds of aerosolized gaseous weaponry, but that’s just a guess.
Firebombing heats things up, and kills vegetation that keeps things cool. Aerosols and other particulates temporarily reflect extra sunlight back to space.
Just a hypothesis.