Is Global Warming Making Tornadoes Worse?

[RYSE cross-post]

Like most natural disasters, the tragic tornadoes in the Southeast and Midwest have triggered a veritable storm of media attention. One question that has come up repeatedly in both mainstream and environmental outlets is this: Could global warming be making tornadoes stronger and more frequent?

Joe Romm, one of the Web’s most thorough climate bloggers, published a detailed post on the subject. He quoted two scientists “who have done more research and publication on extreme weather and climate change than most,” Kevin Trenberth and Tom Karl. Trenberth is head of the Climate Analysis Section of the National Center for Atmospheric Research, and Karl is the director of NOAA’s National Climatic Data Center.

Karl explained that, while several studies show that conditions favorable for tornadoes are more common with more greenhouse gases, “the results are not conclusive.” However, “…what we can say with confidence is that heavy and extreme precipitation events often associated with thunderstorms and convection are increasing and have been linked to human induced changes in atmospheric composition.”

Trenberth, meanwhile told the New York Times that “it’s not the right question to ask if this storm or that storm is due to global warming, or is it natural variability. Nowadays, there’s always an element of both.”

April 2011 did set a new monthly record of 875 tornadoes in the U.S., which coincided with record high temperatures throughout the world. We know the climate is changing, so it seems logical that tornadoes, which are part of the climate, should be affected. But overall, it seems that the specific connection between greenhouse gases and tornadoes has not been explored deeply enough to produce a definite answer.

We must not lose sight of the big picture, though. We’re seeing not just tornadoes, but also record droughts and wildfires, unusually heavy rainfalls, historic floods, and deadly heat waves, in the U.S. and throughout the world. In addition, NOAA has reported that our current emissions path could lead to semi-permanent Dust Bowls in the Southwest and other regions. Experts have been warning for years that climate change would make events like these more common, and in this case, the connection with greenhouse gases is well understood.

Whether or not monster tornadoes add to the proof that our climate is disrupted, they show, painfully, how much our civilization relies on a stable environment, and how dramatic changes in weather patterns can cause damage that even the wealthiest nations struggle to shake off.

Bill McKibben showed us the big picture in his piece for the Washington Post:

Caution: It is vitally important not to make connections….It is far better to think of these as isolated, unpredictable, discrete events. It is not advised to try and connect them in your mind with, say, the fires now burning across Texas—fires that have burned more of America by this date than any year in our history. Texas, and adjoining parts of Oklahoma and New Mexico, are drier than they’ve ever been—the drought is worse than the Dust Bowl. But do not wonder if it’s somehow connected….

There have been tornadoes before, and floods—that’s the important thing. Just be careful to make sure you don’t let yourself wonder why all these records are happening at once: why we’ve had unprecedented megafloods from Australia to Pakistan in the last year. Why it’s just now that the Arctic has melted for the first time in thousands of years….

Because if you asked yourself what it meant that the Amazon has just come through its second hundred-year-drought in the last four years, or that the pine forests across the western part of this continent have been obliterated by a beetle in the last decade—well, you might have to ask other questions. Like, should President Obama really just have opened a huge swath of Wyoming to new coal-mining? Should Secretary of State this summer sign a permit allowing a huge new pipeline to carry oil from the tar sands of Alberta? You might have to ask yourself: do we have a bigger problem than four-dollar-a-gallon gasoline?

….Better to join with the US House of Representatives, which earlier this spring voted 240-184 to defeat a resolution saying simply “climate change is occurring, is caused largely by human activities, and poses significant risks for public health and welfare.” Propose your own physics; ignore physics altogether. Just don’t start asking yourself if last year’s failed grain harvest from the Russian heatwave, and Queensland’s failed grain harvest from its record flood, and France and Germany’s current drought-related crop failures, and the death of the winter wheat crop in Texas, and the inability of Midwestern farmers to get corn planted in their sodden fields might somehow be related. Surely the record food prices are just freak outliers, not signs of anything systemic….

If you got upset about any of this, you might forget how important it is not to disrupt the record profits of our fossil fuel companies. If worst ever did come to worst, it’s reassuring to remember what the US Chamber of Commerce told the EPA in a recent filing: there’s no need to worry because “populations can acclimatize to warmer climates via a range of range of behavioral, physiological, and technological adaptations.” I’m pretty sure that’s what they’re telling themselves in Joplin today.

Enough said.


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