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Did Global Warming Destroy My Hometown?

Like many other towns, Joplin’s policy is to sound a three-minute siren when a storm with winds stronger than 75 mph is approaching town, regardless of whether an NWS agency has issued a watch or warning. So at 5:11 on May 22, after local emergency managers were informed that a funnel cloud had been sighted over southeast Kansas, the city sounded a siren. But warning too early can be dangerous, particularly in a siren-jaded area. The NWS study describes one man’s confused, lackadaisical response: “(1) Heard first sirens at 5:11 p.m. CDT (estimated 30–35 minutes before tornado hit). (2) Went to the TV and heard NWS warning from TV override that indicated tornado near airport drive seven miles north (polygon #30) of his location. (3) Went on porch with family and had a cigar.”

Twenty-seven minutes later, the man heard another set of sirens. At this point, he “thought something wasn’t right,” so he went back inside and turned on the TV, where meteorologists were still warning that the threat was north of town. Then his wife yelled “Basement!” The report concludes this summary of events thusly: “Tornado hit as they reached the top of the basement stairs, destroying their home.”

If I had been living in Joplin that day, I probably wouldn’t have thought to go to the porch and smoke a cigar. But I almost certainly would have walked outside and looked at the sky. Only when the horizon turned green and the dogs began howling would I have hurried to the basement.

One way to fight warning fatigue could be using sirens with different pitches or rhythms to warn of different events. The idea that such an adjustment might be necessary seemed to annoy Bill Davis, head of the NWS forecast office in Springfield. “A warning is a warning,” he vented to the Joplin Globe. “How many adjectives and adverbs do we have to use to make the point that there’s a possibility you could die?”

Dennis S. Mileti, a University of Colorado sociologist who has studied public warnings, has explained that none of this should have surprised the NOAA researchers. “Most people rarely, if ever, experience nature’s extremes in the form of natural and other disaster types,” Mileti has written. “The result is that most people do not perceive risk. Instead, most think they are safe from nature and other violent forces.”

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The most natural way to determine whether global warming is altering tornado patterns is to look for changes in tornado statistics and then see whether climate models can explain those changes. Credit: NOAA Photo Library/flickr. 

The most natural way to determine whether global warming is altering tornado patterns is to look for changes in tornado statistics and then see whether climate models can explain those changes. But the lack of reliable historical tornado data makes this kind of study challenging, at best. And tornadoes are poorly understood to begin with. Scientists still aren’t entirely sure why one particular rotating thunderstorm transforms into a funnel cloud while another one doesn’t.

Scientists call the process of spotting climate variability and attempting to isolate the contribution of man-made climate change “detection and attribution.” Researchers have been doing detection-and-attribution studies on well-understood, well-documented phenomena such as temperature changes and rainfall patterns for more than a decade.

Nonetheless, even scientists who believe that climate change is likely to lead to more events like the Joplin tornado hesitate to draw conclusions about what is going on with the weather right now. In the days after the storm, the editors at the environmental website Yale Environment 360 asked several climate experts to answer the question: Is extreme weather linked to global warming? Andrew Watson, a professor of environmental sciences at the University of East Anglia in England, responded, “My answer to this question as posed is no. However, if you were to ask instead whether I expect that human-caused climate change will lead to more extreme weather events, the answer would be yes.”

This type of reticence surely comes in part from healthy scientific skepticism — the hesitancy to over-interpret data and the impulse to accumulate decades’ worth of statistics before drawing conclusions. But it also seems likely that climate scientists are triply cautious with their public statements because of they way they’ve been dragged into the culture wars. Recall that the university where Andrew Watson works was implicated, and then vindicated, in the phony scandal called Climategate, in which skeptics used out-of-context bits from stolen e-mails to make it sound as if researchers were engaged in some great conspiracy. Climate scientists have become the abortion doctors of the scientific establishment: maligned, ridiculed, harassed, and even physically threatened. Several climate scientists in Australia, which had been debating a tax on carbon emissions, received so many death threats that their universities moved their offices to “secure facilities.”

Kevin Trenberth, a senior scientist at the Climate Analysis Section of the U.S. National Center for Atmospheric Research, is more willing than most climate scientists to link current extreme weather with climate change. He explained to me that climate change is not directly causing events such as the Joplin tornado. It is, however, “loading the dice” by increasing the amount of energy in the atmosphere, making events that would occur naturally all the more powerful and violent.

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