The Philippines continues to stagger in the aftermath of Typhoon Haiyan, the most powerful tropical storm to make landfall in recorded history. Our thoughts are with the victims — and the question gripping environmentalists everywhere: How much was climate change to blame for the intensity of Haiyan or the devastation it caused? (Up to 10,000 deaths at latest count, with an economic toll that could hit US$14 billion, according to one report.)
Even George Clooney has weighed in on the question. Unfortunately, although he played an astronaut in “Gravity,” he’s not a scientist. What do real climate scientists (and the literature) say? The Cooler makes the rounds and finds a scatterplot of answers:
1) A TINY INFLUENCE AT BEST — BUT MORE HAIYANS ARE ON THE WAY
Bryan Walsh at TIME says that, while the “sheer power of Haiyan, as well as the still uncounted human devastation it has wrought, all but assures that the super typhoon will become a symbol of climate change for years to come,” it’s muddy at best whether we can definitively attribute any Haiyan’s strength to global warming. He quotes NASA climatologist Bill Patzert telling the Pasadena Star-News that “The fingerprint is very small, if at all. If the winds are 200 mph, global warming might have contributed 5 mph to that 200 mph.”
But the scientific uncertainty is beside the point, Walsh continues, because this storm represents the future.
“Models point to stronger, if not necessarily more frequent tropical cyclones as the globe continues to warm,” he writes, “though that signal may not become clear until later in the 21st century.” See, for instance, this July PNAS study by MIT climatologist Kerry Emanuel, which predicts that both “the frequency and intensity during the twenty-first century in all tropical ocean regions” will increase — particularly the western North Pacific, where Haiyan went on its deadly spree.
2) LIMITED EVIDENCE YES
On the other hand, Quirin Schiermeier of Nature surveys the science and reports that, while the warmer sea surface temperatures climate change is causing potentially could intensify tropical storms, that effect could be blunted by a concomitant increase in shearing winds — which tend to knock down extreme storms. And while there’s some evidence that tropical storms have gotten more intense since 1980, Schiermeier notes, we only have quality data on this trend from the north Atlantic, not elsewhere.
Schiermeier also cites the Emanuel 2013 study, but warns that such predictions need to be inferred from modeling results, since the models themselves aren’t fine-scale enough to simulate “relatively small-scale atmospheric disturbances such as tropical storms.”
3) NO, BUT WE MIGHT KNOW MORE IN 30 YEARS
Meterologist Dan Satterfield, who blogs for the AGU Blogosphere family, calls claims that Haiyan was “a result of climate change….nothing short of ridiculous.”
Climate change, writes Satterfield, affects all weather, “but not any one event.” While global warming will mean an increasing number of more extreme weather events in the future, the future climate shift curve still includes less dramatic events as well — so “claiming a big snowstorm disproves climate change is just as silly as claiming a super typhoon is the result of one.”
Satterfield’s takeaway: We’re already seeing this shift in higher temperatures, but aggregate trends in storms will take more time to reveal themselves.
4) YES, ABSOLUTELY — AND LET’S DO AN ATTRIBUTION STUDY
Following on Satterfield, the standard line from many climatologists about attributing individual weather events to climate change is that such science will take years (although we’re getting closer).
Wait a minute, Myles Allen of the University of Oxford tells Damian Carrington of the Guardian: Science could now determine just how much climate change influenced Haiyan…if we only dedicated sufficient resources to it. “If we used the same tools as are used now to make seasonal weather forecasts,” he tells Carrington, “there would be a straightforward answer.”
“We should know now how climate change is affecting us rather than how it will affect us in 100 years’ time,” Allen continues. “It is a common misconception that climate change affects everyone. It affects some people a lot and others not very much — but we don’t know who is who.”
But here’s what we do know, writes Carrington: Some scientists think climate change is making tropical storms bigger and badder by increasing the temperature gradient between sea level and the top of the storm — “as this gradient is the heat engine that drives the storm.” In addition, he quotes a Nature Geoscience paper from 2010 that predicted global warming will produce fewer but more severe tropical storms.
5) DOESN’T MATTER: CLIMATE CHANGE USUALLY HITS THE GLOBAL POOR THE HARDEST, REGARDLESS
If you find the is-it-or-isn’t-it debate getting a little stale, Anne Lowrey of The New York Times Economix blog has a fresh take: a geographic and economic analysis of why the impacts of climate change will always hit the world’s poor the hardest — even in prosperous societies.
While rich countries might see “a disproportionate impact from global warming,” Lowrey writes, “poorer, lower-latitude regions are expected to face desertification and more-intense storms” — with sea-level rise some 15-20% higher in the tropics than the global average.
In addition, the poor face a double-whammy globally: They generally live in places more vulnerable to climate change’s effects (like flood zones), and the countries in which they live are generally poorer in the aggregate and thus have less resources and flexibility to adapt to a changing climate.
Correction (13 November 2013): The line about Kerry Emanuel’s study in item #1 should have read “which predicts that both ‘the frequency and intensity during the twenty-first century in all tropical ocean regions’ will increase.”