What About Global Warming and Tornadoes?

There has been recent discussion about a possible link between the recent rash of mid-west tornadoes and global warming. Bill McKibben implies a link in his 5/23/11 Opinion Piece in the Washington Post. Discussion of this assertion is warranted.

In 2010, John Holdren, President Obama's Assistant for Science and Technology, and Director of the White House Office of Science and Technology Policy, spoke at Berkeley on Science and Technology for Sustainable Well-Being. He points out that the phenomena called Global Warming is well established (although, as any scientific hypothesis, subject to potential overturn through further investigation, but this is very unlikely for a phenomena as widely documented and successfully modeled as global warming).

The increased energy density of a warmer atmosphere is predicted by extensive numerical models to lead to intensified droughts and storms. Holdren suggests that rather than Global Warming, we should call this phenomena Global Climate Disruption.

Modeling indicates that the frequency of tornadoes is not expected to increase - while enhanced temperature of  warm and humid air masses colliding with cold air masses makes tornadoes more likely, a decrease in atmospheric shear with increased global temperature is expected to counteract an increase in tornado frequency. However, an increase in the intensity of tornadoes that do form may be a  result of global warming, and may be evident in the EF5 tornadoes that have recently ravished Tuscaloosa Alabama and Joplin Missouri (although I would suggest that more modeling would be appropriate before possibly stating this more strongly).

Even though we cannot be 100% confident of anthropogenic global warming, and consequent global climate disruption, I believe we should move very aggressively toward implementing policy (e.g., a carbon tax and rebate) and technology (e.g., solar power, and sequestration of carbon dioxide in building materials) to reduce atmospheric carbon dioxide content to 350 parts per million - see James Hansen's 2008 paper on why this limit is expected to be required to avoid a potential disaster for humanity.

Holdren suggests that policy makers should not ignore global warming - thus betting with the public's welfare against unfavorable odds. I agree. As McKibben, I find reprehensible the vote this spring by the U.S. House of Representatives (240 to 184)  to defeat a resolution saying that “climate change is occurring, is caused largely by human activities, and poses significant risks for public health and welfare.”

I suggest that McKibben's assertion of a link between global warming and the damage to Joplin and Tuscaloosa should not be casually dismissed.