In the aftermath of Hurricane Sandy, there has been much discussion about global warming and increased hurricane intensity and damage. An example can be found in a recent Huffpo article which quotes some prominent climate scientists:
“But we can see that climate change is playing a role in setting the context for these storms,” (Michael) Mann continued, “in particular the record levels of North Atlantic ocean warmth that is available to feed these storms with energy and moisture.”
“Kevin Trenberth, head of the Climate Analysis Section at the USA National Center for Atmospheric Research and one of the world’s foremost experts on changes to global energy and water cycles, suggested in an email message that Hurricane Sandy represents the “new normal.”"
http://www.huffingtonpost.com/2012/10/29/hurricane-sandy-climate-change_n_2038859.html
However, recent peer reviewed study on this topic has come out in the Journal of Climate: Weinkle, J., Maue, R. and Pielke Jr., R. 2012. Historical global tropical cyclone landfalls. Journal of Climate 25: 4729-4735. They conclude that while damage and economic loss has increased recently “…the increase in losses can be explained entirely by societal changes (such as increasing wealth, structures, population, etc.) in locations prone to tropical cyclone landfalls, rather than by changes in annual storm frequency or intensity.” http://www.co2science.org/articles/V15/N50/C2.php
And in an article on this study, Peilke notes the following:
- 1971 had the most global landfalls with 30, far exceeding the second place, 25 in 1996.
- 2011 tied for second place for the fewest global landfalls with 10 (and 3 were intense, tying 1973, 1981 and 2002).
- The US is currently in the midst of the longest streak ever recorded without an intense hurricane landfall.
– There have been frequent four-year periods with more than 25 landfalling major hurricanes, or more than a 100% increase of what has been observed over the past 4 years.
http://www.globalwarming.org/2012/12/17/no-long-term-trend-in-frequency-strength-of-landfalling-hurricanes/
Pielke also concludes: “Anyone who’d like to argue that the world is experiencing a ‘new normal’ with respect to tropical cyclones is simply mistaken.”
So what does the evidence and the science say?
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I’m expecting someone to comment on the hurricane expertise of Mann and Trenberth vs. Pielke. After all, expertise is usually an issue in questions like this.
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@Fannylight: From latest report from the IPCC on weather extremes, SREX Summary for Policy Makers (Table SPM.1):
“Observed: Low confidence in any observed long-term (i.e., 40 years or more) increases in tropical cyclone activity, after accounting for past changes in observing capabilities.” http://ipcc-wg2.gov/SREX/images/uploads/SREX-SPMbrochure_FINAL.pdf
Although from the same table the projections do call for more intensity in some basin and more precipitation. But that has not yet been observed so it’s still speculation and nothing like a “new normal”.
Chosen Answer:
The new normal is people misrepresenting science to score points against people whom they disagree with. Actually, that’s probably an old normal.
Pielke and co looked at storms which hit land. Not all storms, only the ones that cross land.
Trenberth said “The past few years have been marked by unusually severe extreme weather characteristic of climate change. The oceans are warmer and the atmosphere above the oceans is warmer and wetter. This new normal changes the environment for all storms and makes them more intense and with much more precipitation.” (from Mike’s link).
Now, I’m not saying that the Pielke research is flawed. I’m saying his assertion that Trenberth is wrong based on Pielke’s own research is flawed. He’d need to show that Trenberth is also disregarding the proportion of storms which do not cross land, or produce another paper which analyses all the storms and contradicts Trenberth’s claims about increased intensity and precipitation for Trenberth to be convincingly proven wrong.
by: Gas By Fannylight
on: 24th December 12