Looks like what we’d expect from warming
It sure looks like warming, wrote Richard Alley, an expert on climate and ice at Pennsylvania State University, via email. “Our usual scientific response is to say that human burning of fossil fuels has made the events more likely, and they happened,” but conclusive proof is not available. “You as journalists, and the public in general, HATE that. But it’s probably the best answer.
“In a warmer world, we expect more record highs and fewer record lows, more heat waves and fewer cold snaps. That pattern is being observed. Warmer air can ‘hold’ more water (saturation vapor pressure increases with temperature), so if air is warmer when a rainstorm happens, then the rain can be more intense.
“In addition, there is a fairly strong reason to expect that in a warming world the subtropical dry zones (which include the Sahara and the Kalahari, and influence the U.S. Southwest, including parts of Texas) will intensify and expand poleward at least somewhat.
“Suppose you’re playing dice with me, and after you lose, you discover that I stuck some carefully positioned weights inside them. Out in the climate, the dice are now loaded, but not nearly as much as they will be in the future if we keep burning fossil fuels and releasing the CO2 to the air. It is hard to prove that any particular event was extreme because of global warming … but for many events (record heat, drought and flood) it is harder to prove that humans did not influence the outcome, just as it is very hard to prove that my loaded dice didn’t affect the game.”