By ANDREW C. REVKIN
MAY 22, 2013
As I explained earlier this week, questions related to any impact of human-driven global warming on tornadoes, while important, have almost no bearing on the challenge of reducing human vulnerability to these killer storms. The focus on the ground in Oklahoma, of course, will for years to come be on recovery and rebuilding — hopefully with more attention across the region to developing policies and practices that cut losses the next time.
The vulnerability is almost entirely the result of fast-paced, cost-cutting development patterns in tornado hot zones, and even if there were a greenhouse-tornado connection, actions that constrain greenhouse-gas emissions, while wise in the long run, would not have a substantial influence on climate patterns for decades because of inertia in the climate system.
Some climate scientists see compelling arguments for accumulating heat and added water vapor fueling the kinds of turbulent storms that spawn tornadoes. But a half century of observations in the United States show no change in tornado frequency and a declining frequency of strong tornadoes.
Does any of this mean global warming is not a serious problem? No.
It just means assertions that all weird bad weather is, in essence, our fault are not grounded in science and, as a result, end up empowering those whose prime interest appears to to be sustaining the fossil fuel era as long as possible. I was glad to see the green blog Grist acknowledge as much.
On Tuesday, I sent the following query to a range of climate scientists and other researchers focused on extreme weather and climate change:
The climate community did a great service to the country in 2006 in putting out a joint statement [from some leading researchers] on the enormous human vulnerability in coastal zones to hurricanes — setting aside questions about the role of greenhouse-driven warming in changing hurricane patterns….
In this 2011 post I proposed that climate/weather/tornado experts do a similar statement for Tornado Alley.
I’d love to see a similar statement now from meteorologists, climatologists and other specialists studying trends in tornado zones. Any takers?
Before you dive in to the resulting discussion, it’s worth reading Andrew Freedman’s helpful Climate Central piece, “Making Sense of the Moore Tornado in a Climate Context,” and a Daily Beast post by Josh Dzieza. The National Oceanic and Atmospheric Administration has posted a helpful new fact sheet, “Tornadoes, Climate Variability, and Climate Change.”
Read on for the conversation on tornadoes and global warming, with some e-mail shorthand fixed.
First, I’m posting the comments that were focused on policy, then those focused on the details of the science:
Roger Pielke, Jr., professor of environmental studies, the University of Colorado:
People love to debate climate change, but I suspect that the community’s efforts are far better placed focusing attention on warnings and response. That is what will save lives and continue the really excellent job that has been done by NOAA and the National Weather Service. I’d much rather see a community statement highlighting the importance of NOAA/NWS funding!
There will always be fringe voices on all sides of the climate debate. With the basic facts related to tornadoes so widely appreciated (unlike perhaps drought, floods, hurricanes), I think that those who see climate change in every breeze are not particularly problematic or worthy of attention.
Here are some of those basic facts:
1. No long-term increase in tornadoes, especially the strongest ones.
2. A long-term decline in loss of life (the past year saw a record low total for more than a century).
3. No long-term increase in losses, hint of a decrease.
4. To date 2013 has been remarkably inactive.
5. The Moore tornado may have been the strongest one this year, bad luck had it track through a populated area (Bill Hooke brilliantly explained the issue here).
6. That said, climatology shows that Moore sits at the center of a statistical bullseye for tornado strikes for May 20th.
Kerry Emanuel, professor of atmospheric science, Massachusetts Institute of Technology (a signer of the 2006 statement):
I see the political problem with tornadoes as quite different from the hurricane problem we wrote about some years ago. To my knowledge, there are no massive subsidies to build in tornado regions, nor is insurance premium price fixing a big problem. Also, federal flood insurance is largely irrelevant to this problem. About the only thing in common is federal disaster relief, but it is hard to believe that people only build houses in huge swaths of tornado-susceptible territory because they believe they will be bailed out.
As you mention in your blog, the issues here revolve around such practical measures as safe rooms, and the role of government in mandating or subsidizing them. Perhaps one positive outcome of the latest horror story is that safe rooms in public buildings such as schools and hospitals will be mandated, given that they are apparently not all that expensive.
In my view, the data on tornadoes is so poor that it is difficult to say anything at all about observed trends, and the theoretical understanding of the relationship between severe thunderstorms in general (including hail storms) and climate is virtually non-existent. I regard this as a research failure of my profession and expect there will be a great deal more work on this in the near future. What little exists on the subject (e.g. the Trapp et al. paper from a few years ago) suggests that warming will increase the incidence of environments conducive to severe thunderstorms in the U.S. But this counts on climate models to get these factors right, and it may be premature to put much confidence in that.
Daniel Sutter, a professor of economics (focused on tornadoes), Troy University, offered the following thought after citing the Dot Earth comments of Kevin Simmons, his co-author on a recent book on tornadoes and society:
I would just add that the high cost per life saved through safe rooms which Kevin and I find in our research really indicates that tornado safety is about reducing and not eliminating risk. Safe rooms provide essentially absolute protection, but are expensive enough that many would likely judge them too expensive. We need to focus on ways to reasonably reduce risk. For instance, have engineers inspect schools and make sure the safest areas are indeed being used for shelter, or to see if there are relatively inexpensive designs that could strengthen interior hallways some.
I hate to say anything before I know for sure what the final story is from the Plaza Heights school, but the two schools yesterday appear to have provided pretty decent protection, especially since many homes around Briarwood school looked totally destroyed. Wind engineers have developed safe room designs which are great and engineering marvels, but we probably need designs that provide a good measure of safety at a portion of the price.0
Also with regard to your previous post about flimsy homes, consider the contrast between how cars and houses are marketed. Cars are sold under brand names, and we have a dual system of federal regulation of designs for safety and auto makers designing cars that are safer than federal regulations require, with certification by the Insurance Institute for Highway Safety. Houses are mainly sold without brand names (I couldn’t tell you who built the house I own here in Alabama) with safety assurances coming through building codes. Many times we see that homes perform poorly in tornadoes or hurricanes, while during a commercial break on the Weather Channel last night there was a car ad touting the model’s crash test rating from the IIHS. If houses are indeed flimsy, there is probably a systematic reason for this. Read more…