Richard Alley in USAToday: Why the Extremes?
April 20, 2012
Above, Richard Alley demonstrates how to patiently answer questions from someone who has no interest in learning the answers.
Below, Dr. Alley comments on this spring’s extreme weather events.
Did humans contribute to the record heat of March and the strength of April’s tornadoes across much of the U.S.? Science still says, “Maybe, maybe not.” But we’re rolling the dice in a serious game where the “jackpot” means we lose.
There’s very high scientific confidence that our fossil-fuel burning and other activities, which add carbon dioxide to the air, are turning up the planet’s thermostat. In a warmer world, we expect more record highs and heat waves but fewer record lows, just as we’re observing. Warmer air can carry more water vapor, so a warmer rainstorm can deliver more inches per hour. Hair dryers have a “hot” setting for good reasons, and warmer air between rainstorms can dry out the ground faster.
Thus, we expect rising CO2 to bring more floods in some places and more droughts in others, with some places getting more of both. That might seem contradictory, but it’s not. And with more energy to drive hurricanes, the peak winds may increase, even if the number of storms drops.
Unfortunately, if three rotten cherries come up on the climate slot machine before we master sustainable energy, we could lose the jackpot. Science hasn’t found a plausible way for rapidly rising CO2 to turn Earth into Eden, but there is at least a slight chance of a rapidly collapsing ice sheet flooding the coasts, or widespread droughts and heat stress risking famine, or other very large problems.
Much of my research, and that of many colleagues, has been devoted to replacing these worrisome “what if’s” with hard numbers. And in some cases, the worries have grown smaller as we learned more. But in other cases, the worries are still there and might even be bigger.