Cowering In The Uncertainty Basement
LINCOLN, NE – At 11:30pm, after thirteen hours of math ecology talks, I was dead to the world. Almost. I just couldn’t figure out why someone had suddenly parked all the city’s fire engines outside our hotel, or why their sirens sounded so odd.
Despite my best attempts to burrow under the blankets and away from the sound, my brain was slowly returning to life. “Isn’t this tornado country?” I wondered groggily.
The answer – and an adrenaline-fueled acceleration of thought processes – came when a hotel staffer pounded on the door, shouted “Tornado coming – get to the basement!” and disappeared into the stampede of hotel guests heading for the stairwell.
I shook my roommate awake, grabbed a sweater and notes on my latest mathematical model, forgot my eyeglasses and my shoes, and pounded down the stairs.
As my fellow conference-goers and I crowded into the (nicely finished) hotel basement with the rest of the hotel’s guests, we exchanged looks of nervous excitement. Most of us had never experienced a tornado warning before: What a great story we’d have to tell when we returned home from Nebraska!
Fortunately for us, it would remain a great story: No tornadoes touched down in Lincoln that night, though other plains cities were not so lucky.
We won’t be able to tally this twister season’s damages until summer’s end, but with April’s typical spike in thunderstorms and tornadoes, speculation is rampant. And, as an increasingly public debate on the significance – and even existence – of climate change rages on, some of the discourse is getting a little volatile.
Especially when, earlier this month, a CNN meteorologist called a Texas twister evidence of climate change.
Her connection was tenuous, but not unfounded: As increasing atmospheric carbon dioxide levels trap more of the sun’s heat, we expect the associated climatic shifts to produce “more extreme” weather.
Late last year, the Intergovernmental Panel on Climate Change released a report specifically addressing the link between climate change and extreme weather. The Panel’s scientists carefully summarized the predicted changes to historic weather patterns, and, perhaps more importantly, included the relative certainty of their predictions.
For example, the world’s best climate scientists concur that, on average, hot days will get hotter, heat waves will intensify, and hurricanes will get more frequent. But unfortunately for the CNN meteorologist, because the fine-scale, long-term data and models needed to predict local weather aren’t available, the scientists can’t say anything yet about tornadoes.
However, because warmer air carries more water, just as we expect more tropical hurricanes, we also expect more Midwestern thunderstorms. And since t-storms spawn tornadoes, the meteorologist may yet be proven correct.
Why, though, is there so much uncertainty around how climate change will alter our daily lives?
Part of the reason stems from the difference between climate and weather: The former is a broad pattern, described by long-term averages (e.g., seasonal temperature) and seasonal summations (e.g., annual rainfall). Weather, by contrast, is a transient phenomenon: a two-day cold snap, or a splash-and-dash shower.
Weather, the daily product of climate, is inherently more variable than its statistically-packaged long-lived parent. Just as it’s much easier for you to predict the average number of runs per game of the Giants than it is to nail the score on every game of the season, it’s easier for scientists to predict global or regional climate trends (averaged across both time and space) than it is for them to tell you which weekend to pick for your next bar-b-que.
Take, for example, the measly success rate of your local weatherman (though I think ours predict rain just to spice things up a bit). If that’s the best regional experts and day-of radar can do, no wonder our global climate models can only give us the big picture.
Of course, it’s weather and, in particular, extreme weather that makes the biggest impression. It’s the tornado that rousts you from bed; the windstorm that delays your flight; the drought that tightens your water belt. We’d love to be able to predict these extremes, to have plenty of advanced warning when to evacuate in advance of a major hurricane, and to know which crops to plant given the summer’s coming rain pattern.
That’s why the prediction we can make – that weather will become more variable, making these extremes more extreme – is so very troubling. In addition to loss of life (in third world countries) and property damage (already being built into increased insurance premiums) produced by intensified storm systems, we’ll also have to face growing insecurity in our food supply, as wet places become waterlogged and dry places grow parched.
However, the more extreme weather events we have, the more opportunities I’ll get to see my field’s leaders lounging about in their pajamas. Note to self: Remember eyeglasses next time.