Climate Change Could Leave Florida Hotter, Smaller

You’ve got to hand it to Florida Gov. Charlie Crist. Even though he’s cut from the same political cloth as fellow Republican Sonny Perdue, Georgia’s governor, Crist is doing a lot more than praying when it comes to dealing with climate change.

Still, you could understand if Crist and his fellow 18 million-or-so Floridians — myself included — felt the need to throw a few extra appeals heavenward last week. That’s when Tufts University released a new report that — for residents of the Sunshine State — reads like a horror story, with them as the main characters.

“Florida and Climate Change: The Costs of Inaction” sketches out two alternative scenarios for what Florida will look like at mid-century and century’s end. One potential future — the better one — comes if we all take action now to reduce greenhouse gas emissions by half by 2050, and by three-fourths by 2100. The other one — the now infamous “business-as-usual” case — leaves Florida far hotter, smaller and poorer than today.

By rapidly stabilizing greenhouse gas emissions globally, Florida could manage to escape with an average temperature increase of only 2.2 degrees Fahrenheit and a sea-level rise of only 7.1 inches. Keep doing what we’re doing, though, and the Sunshine State takes a big hit of both heat and water: an average temperature increase of 9.7 degrees Fahrenheit, and a sea-level increase of 45.3 inches.

At that rate, some 4,700 square miles — about 9 percent of the state’s land area — would be under water by 2060, according to the Tufts study. That includes 99.6 percent of the state’s southwestern-most county and the Keys, and 70 percent of Miami-Dade County. Areas that would be inundated are now home to 1.5 million people, as well as to two nuclear reactors, 68 hospitals, 74 airports, 341 hazardous-material cleanup sites and 19,684 historic structures.

Oh, and if you think Florida’s hot and muggy now, consider this: “Miami will become several degrees hotter than today’s Bangkok (probably the world’s hottest, most humid major city at present), and daily highs in many Florida cities will exceed 90 degrees nearly two-thirds of the year.”

Of course, among the areas to go under first will be some of the state’s greatest natural attractions: its sandy beaches, the Everglades and the Keys. The resulting financial hit to tourism is likely to total $40 billion by mid-century, and $167 billion by century’s end.

“To reject a potential 10ºF increase in temperature and 3 feet or more in sea-level rise this century, Floridians — and residents of other U.S. states and of other nations — must commit to beginning in the very near future to take steps to substantially reduce global greenhouse gas emissions,” write the report’s authors, Elizabeth A. Stanton and Frank Ackerman. “The only other available option is to place a very risky bet — that somehow, despite the most current scientific knowledge, business-as-usual emissions will not trigger a climate catastrophe. If we gamble and lose, we and our children cannot walk away from the consequences.”

For all the scary stuff in the Tufts reports, the document also features one of the most elegantly clear explanations for why we can’t assume uncertainties in today’s climate predictions mean we might be able to escape global warming unscathed.

Imagine, Stanton and Ackerman say, that predicting future climate is like drawing cards from a standard 52-card deck. While you can’t say with certainty what number you’ll draw, over time, the average number will approach seven (if you count aces as ones and face cards as 11, 12 and 13). If the dealer takes out all the six, seven and eight cards, your average draw will still be seven over time — but the odds of you picking a very low or a very high number have just increased. And if the dealer adds extra face cards instead of removing the sixes, sevens and eights, the average number you’ll draw over time will be higher than seven.

The authors then conclude the analogy with their kicker:

“Climate change is like drawing a card from a changing deck,” they write. “There is no way of predicting the next card you will draw from a well-shuffled deck. But the message of climate science is that the deck of climate possibilities is changing in disturbing directions, both toward more variability and more extreme outcomes, and toward worsening averages. The same logic applies in reverse: reducing greenhouse gas emissions will not guarantee better weather next year, but it will ensure that in the future we and our descendents will be able to draw from a better deck.”