Now, consider hydrological extremes. By hydrological extremes I mean droughts and floods. First, some theory. Since we add heat-trapping gases like carbon dioxide to the atmosphere, which, in turn, add energy to the earth's surface, some of that energy will be used to evaporate water. No one who is knowledgeable disputes that.
More evaporation globally means more rainfall globally.
Thus when the atmosphere configures itself for locally heavy rains, more evaporation means heavier rains on average. Likewise, as farmers or lawn waterers know, when the atmosphere is in a drier mode, higher temperatures suck more water from the soils. Taken together, these physical arguments provide the rationale for forecasting increased droughts and floods from global warming. But this is physical reasoning, not proof. So now to some data.