Should We Talk About the Weather?
How to Navigate Climate Science During Hurricane Season
SOURCE: NOAA/AP
We should use hurricanes to discuss global warming, but we have to do it with rigorous fidelity to the current state of scientific understanding. Above: Cyclone Gonu over the Arabian Sea in 2007.
With a very active hurricane season upon us—and Hurricane Ike about to enter the Gulf of Mexico and, it is feared, explode in intensity—a perennial topic arises: How can one discuss, responsibly, the relationship between hurricanes and global warming?
Hurricanes are incredibly dramatic—we’re talking about storms capable of swelling to the size of Texas and churning out as much power as the entire world’s electricity generating capacity.
After all, for those advocates and bloggers who desperately want to draw attention to climate change, storms pose an often irresistible opportunity. And who can blame them: Global warming is a subject that the media has a great deal of trouble handling, because it is a slow-moving, uncertain, long-range threat that always has to compete with sudden, urgent problems and scandals for attention. Accordingly, there are many grounds upon which to slam press coverage of climate change (see a full discussion here and here by Columbia Journalism Review‘s Curtis Brainard). Personally, I think one statistic says it all: According to a study by Yale University’s Anthony Leiserowitz, the fantastical 2004 global warming disaster flick, The Day After Tomorrow, garnered ten times as much media attention as the 2001 release of the United Nations’ Intergovernmental Panel on Climate Change’s Third Assessment Report, the definitive scientific study of climate change and its impacts. In short, in the total media arena, a climate change blockbuster with little connection to reality made a vastly bigger splash than the release of the single most important scientific study.
Hurricanes, however, command intense and sustained media attention whenever they threaten. And no wonder: In many ways, they’re much more like a movie than a new scientific paper. Hurricanes are incredibly dramatic—we’re talking about storms capable of swelling to the size of Texas and churning out as much power as the entire world’s electricity generating capacity—and provide plenty of visuals, ranging from sublime satellite images of hurricane eyes to on-the-ground footage of wind-whipped reporters occasionally dodging palm tree fronds and flying billboards. No wonder advocates ranging from Al Gore to, most recently, the National Wildlife Federation have sought to emphasize the hurricane-climate connection.
The science, though, is tricky. There’s a general scientific expectation that the average storm ought to be able to achieve a greater intensity due to climate change’s heating of the oceans—but it’s also quite possible that total storm numbers may decrease, and that different parts of the world will be affected differently. Moreover, regardless of theoretical expectations, there’s an open debate over the extent to which global warming can explain recent, high levels of hurricane activity, of the sort that we’ve seen in the Atlantic region since 1995.
My own view is that while hurricanes can and even should be used to discuss global warming, it must be done with rigorous fidelity to the current state of scientific understanding—something that’s hardly easy to achieve when scientific understanding on this topic is a moving target. Nevertheless, using a language that emphasizes risk rather than certainty—and, of course, avoiding the causal attribution of any individual storm to climate change—generally insulates against criticism. For instance, regarding an eerie, record-breaking storm like 2007′s Category 5 Cyclone Gonu, I might say something like this: “Scientists predict that hurricanes should worsen due to global warming…and when you see a seemingly unprecedented storm like Gonu, doesn’t it at least make you worry that they’re right?”
Gonu occurred in the Arabian Sea, but we can translate a similar argument easily for the Atlantic region. For instance, one might observe that: “Since 2003 in the Atlantic, there have been no less than eight Category 5 hurricanes—an unprecedented number. Even though scientists continue to debate the issue, doesn’t that make you wonder whether global warming could be at work here?”
For Gulf Coasters, meanwhile, there’s an approach that may resonate even more, and that suffers from less scientific uncertainty. One of the most scientifically airtight aspects of climate change is sea level rise, as higher temperatures cause the thermal expansion of seawater and melt land-based ice, which flows into the world’s oceans. This effect is, essentially, built into the definition of global warming, which means we can basically promise, for any coastal area, that seas are already rising and will continue to do so for decades or even centuries to come. As this occurs, any future land-falling hurricane will drive its wall of water substantially further inland than before. Ergo, the hurricane risk increases because of global warming—it’s that simple.
And there’s something else that Floridians, recently drenched by Tropical Storm Fay, might duly note: Global warming also, by definition, increases the intensity of precipitation in storms, because air holds more water vapor at higher temperatures. This is nothing more than basic physics, but its implications are profound. Hurricanes are, in essence, a triple threat—they can hurt you through wind, through their storm surges, and through their sustained downpours. And the downpours, on average, ought to be worse as a result of climate change. Once again, that’s hard to dispute.
However, here’s something that, as a global warming advocate, you really can’t do: Make an opportunistic leap from these arguments about hurricanes to a very different atmospheric phenomenon: tornadoes. As I reported in New Scientist last month, the science in this area is just too new, and too uncertain, to let us predict whether tornadoes ought to become more numerous or worse due to climate change. Indeed, scientists are just beginning to study the effect that climate change may have on the severe thunderstorms that spawn these tiny, short lived, but very intense whirlwinds—but the second order change to tornadoes themselves is far too uncertain to characterize at this time, and impossible to include in climate models due to problems of scale. Making a strong link between recent intense tornadic activity and climate change thus represents true opportunism and ought to be avoided—at least until more studies come in on this very novel and little-researched topic.
In the end, given the uncertainty and the careful language that advocates must use to discuss hurricane threats in the context of climate change, one could argue that better messaging strategies are called for. When presidential candidates, politicians, and the Center for American Progress itself talk about “Green Jobs,” after all, they’re basically talking about climate change, but in an economic context where the science isn’t really subject to dispute, because it isn’t part of the message at all. When storms threaten, we may want to talk about them—but most of the time, for most audiences, messages that involve positive and hopeful economics, rather than uncertain and contested science, are probably the way to go.
Chris Mooney is a contributing editor to Science Progress and the author of two books, The Republican War on Science and Storm World: Hurricanes, Politics, and the Battle Over Global Warming. He blogs on The Intersection with Sheril Kirshenbaum.
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