I just never thought it would be someone respectable, like Peter Gleick.
Let's review what the IPCC has to say about tornadoes (IPCC 4AR WG1 Ch3 FAQ3.3 p308):
Observational evidence for changes in small-scale severe weather phenomena (such as tornadoes, hail and thunderstorms) is mostly local and too scattered to draw general conclusions; increases in many areas arise because of increased public awareness and improved efforts to collect reports of these phenomena.
They clarify this, a little, in section 18.104.22.168, again stressing that the question of tornadoes depends on local measurements, which are too variable to use for any global conclusions. But basically they punt on the issue. Fair enough.
Gleick makes a cursory effort about sticking to the science:
More extreme and violent climate is a direct consequence of human-caused climate change (whether or not we can determine if these particular tornado outbreaks were caused or worsened by climate change).
but then he just can't help himself:
The extreme nature of the ongoing severe weather is well described by Jeff Masters on his Weather Blog. The 3-day total of preliminary tornado reports from this week's outbreak is nearing 300, close to the 323 preliminary tornado reports logged during the massive April 14 - 16 tornado outbreak. That outbreak has 155 confirmed tornadoes so far, making it the largest April tornado outbreak on record.
You don't have to look very far to disprove this -- in fact, you don't even have to look farther than the Drudge Report, which today links to this story:
5 P.M. UPDATE: Hundreds treated at DCH
"The loss of life is the greatest from an outbreak of U.S. tornadoes since April 1974, when 329 people were killed by a storm that swept across 13 Southern and Midwestern states."
When are activists going to learn that they will never make their case by falsifying the science, and that, in fact, they only harm their cause when they do so? You cannot draw conclusions about climate based on weather. You can only do it via long-term (decadal or more) statistics.
Please tattoo this on your foreheads, so you don't ruin this for those of us trying to communicate actual, real science, with all its inconvenient unknowns and uncertainties.