Tornadoes – Blame Sins of Emission?

“Storms Kill Over 250 Americans In States Represented By Climate Pollution Deniers,” announces a blog post on ThinkProgress.Org. If the blogger does not actually claim that the southland is being punished for its sins of emission, he apparently sees poetic justice in the devastation, or at least irony:

The congressional delegations of these states — Alabama, Tennessee, Mississippi, Georgia, Virginia, and Kentucky — overwhelmingly voted to reject the science that polluting the climate is dangerous. They are deliberately ignoring the warnings of scientists.

The real irony, though, is that blaming tornadoes on global warming is unscientific. “Tornadoes whipped up by wind, not climate: officials,” reports Physorg.com. Some pertinent excerpts:

“If you look at the past 60 years of data, the number of tornadoes is increasing significantly, but it’s agreed upon by the tornado community that it’s not a real increase,” said Grady Dixon, assistant professor of meteorology and climatology at Mississippi State University.

“It’s having to do with better (weather tracking) technology, more population, the fact that the population is better educated and more aware. So we’re seeing them more often,” Dixon said.

But he said it would be “a terrible mistake” to relate the up-tick to climate change.

. . .

Craig Fugate, administrator of the Federal Emergency Management Agency (FEMA), also dismissed Thursday climate change as a factor in the deadly tornadoes: “Actually what we’re seeing is springtime,” he said.

. . .

However, the stronger-than-usual tornadoes affecting the southern states were actually predicted from examining the planet’s climatological patterns, specifically those related to the La Nina phenomenon.

“We knew it was going to be a big tornado year,” [David Imy of NOAA] said. But the key to that tip-off was unrelated to climate change: “It is related to the natural fluctuations of the planet.”

If anything, Prof. Dixon does not go far enough. If we consider only the strong-to-violent (category F3-F5) tornadoes — those that have been monitored for decades — the long-term trend is down; the monsters have become less frequent in recent decades.

Source: NOAA, State of the Climate Tornadoes Annual 2008

Climatologist Roy Spencer, who lives and works in tornado-stricken Alabama, demolishes the warming-tornado link on his blog. Some choice excerpts:

If there is one weather phenomenon global warming theory does NOT predict more of, it would be severe thunderstorms and tornadoes.

Tornadic thunderstorms do not require tropical-type warmth. In fact, tornadoes are almost unheard of in the tropics, despite frequent thunderstorm activity.

. . .

For example, the poster child for active tornado seasons was the Superoutbreak of 1974, which was during globally cool conditions. This year, we are seeing much cooler than normal conditions through the corn belt, even delaying the planting schedule. Cool La Nina years seem to favor more tornadoes, and we are now coming out of a persistent La Nina. The global-average temperature has plummeted by about 1 deg. F in just one year.

. . .

It is well known that strong to violent tornado activity in the U.S. has decreased markedly since statistics began in the 1950s, which has also been a period of average warming. So, if anything, global warming causes FEWER tornado outbreaks…not more. In other words, more violent tornadoes would, if anything, be a sign of “global cooling”, not “global warming”.

Anyone who claims more tornadoes are caused by global warming is either misinformed, pandering, or delusional.