A future with a lot of ‘Hotlantas’

By Tom Baxter

It’s going to rain, and we’re not just talking about the next couple of days. The news won’t come as much consolation to Georgia farmers struggling through a multi-year drought, but according to the most sophisticated climate model ever attempted for the eastern United States, their problem 44 years from now won’t be lack of rain, but torrential storms and flooding.

And it will be hot, but it may seem hotter in some places than others.

We can begin speculating about such things because of the unprecedented degree of detail in a study conducted by researchers at the University of Tennessee, Emory’s Rollins School of Public Health and the National Center for Atmospheric Research, published in the Nov. 6 edition of Environmental Research Letters.  In contrast to many earlier models based on broad regional patterns, this study used a methodology called dynamical downscaling, which analizes and makes predictions about areas as small as four square kilometers. The researchers fed an immense amount of weather-related data from 2001-2004 into two supercomputers at UT and the Oak Ridge National Laboratory to make predictions about conditions in the years 2057 to 2059.

What leaps out from this more detailed analysis is that while the South will weather more severe heat waves and floods than it does today, change will be even more dramatic in the Northeast and Midwest. Heat waves will be much more frequent in Georgia, but even more so in New Hampshire, and while the average length of our heat waves will increase by less than a day (.68), the length of those in New Hampshire will increase by an average of 2.13 days. The regions east of the Mississippi will become increasingly like each other, at least as regards the climate.

It’s important to note that the study analyzed only extreme weather events and doesn’t attempt to make broader predictions about climate change, said Dr. Joshua Fu, a professor of civil and environmental engineering at UT. In other words, the model makes the most detailed predictions published so far about how many heat waves there will be across the eastern U.S., how long and intense they will be, and also how much and how many events of extreme precipitation there will be. But it doesn’t try to predict what the weather will be like on the days when those extreme events aren’t occurring.

Fu is also modest about the reach of the current study. The researchers hope to expand the model to encompass up to a decade’s worth of data, but the current sample represents the limits of what two supercomputers, one of them the world’s most powerful, can handle at this time.

“We’re not saying these are perfect results, but these are the results we can get at this moment,” Fu said Monday.

While Fu said that he is “not a preacher for climate change,” this study represents an important inflection point in the scientific discussion on that issue, and perhaps the political discussion as well.

The conservative Georgia blogger Erick Erickson articulated another important change in the conversation recently when he remarked that climate change “seems like a problem we’re going to have to get used to, more than a problem we can cure.” That’s a shift from arguing the change simply isn’t occurring.

But Fu seemed puzzled by the futility of this evolving argument that nothing can be done about the problem, even if there is one.

“Why can’t we do something about it?” he said.

If you know there are going to be more Sandys and Katrinas, for instance, you can make intelligent choices about how to mitigate the damage from these extreme events. This study says, quite specifically, watch out for more Sandys and Katrinas.

The study also includes predictions for the 20 largest cities in the eastern U.S. Therein, amid a mass of gloomy data about the future, lies a thin filament of civic self-interest. It might be unseemly to contemplate an apocalyptic future in such a boosterish way, but, hey, we’re Atlanta.

Make no mistake, Atlanta in 2057, by this model, will be a hotter, stickier place. But if you look at the projections with a Henry Grady eye, things could be worse. We’ll have an average 3.69 more heat waves a year than we do now. But Cleveland, Ohio, will have 5.25 more, and Miami will have 7.55 more. And the increase in duration of our heat waves will be much less than either of these cities. We’ll see an increase of 22.8 millimeters of “extreme rainfall” – the sort that causes floods – but that’s modest compared to an increase of 227.3 in Baltimore and 121.7 in Chicago.

The notion of liveability has always been central to the Atlanta success story. What if the concept were rebooted to enhance our competitive advantage in a harsher future? What if we started experimenting more with ways to reduce the temperature on our heat island, and moderate the effects of heat waves and torrential rain? A possible model for how to start along that path lies, not in some unpronounceable place in Iceland, but just up the road in one of our neighboring cities. We’ll return to that subject soon.

About Tom Baxter

Tom Baxter has written about politics and the South for more than four decades. He was national editor and chief political correspondent at the Atlanta Journal-Constitution, and later edited The Southern Political Report, an online publication, for four years. Tom was the consultant for the 2008 election night coverage sponsored jointly by Current TV, Digg and Twitter, and a 2011 fellow at the Robert J. Dole Institute of Politics at the University of Kansas. He has written about the impact of Georgia’s and Alabama's immigration laws in reports for the Center for American Progress. Tom and his wife, Lili, have three adult children and seven grandchildren.
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