It will be interesting to see how the climate change pseudoskeptics spin the latest research from Kerry Emmanuel. He's the guy whose 2005 paper suggesting climate change is making tropical cyclones stronger prompted the use of the "Hurricane Katrina=global warming meme. Al Gore even used the image of a hurricane emerging from a smokestack to promote An Inconvenient Truth, and his slide show included a large section on a causal connection. But now Emmanuel admits he might have been wrong.
Might is the operative word here. In a new paper in the March issue of Bulletin of the American Meteorological Society he describes "a new technique for deriving hurricane climatologies from global data." Using that new analysis, he and his MIT colleagues ran 200 years of simulations based on the same global climate models used by the IPCC and conclude that a warmer world may not make hurricanes stronger after all. On the other hand, hurricane frequency might increased. Or not. And it depends on what ocean you're talking about.
There is an overall tendency toward decreasing frequency of events in the Southern Hemisphere, consistent with direct simulations of tropical cyclones using global climate models, and power dissipation and storm intensity generally increase, as expected from theory and prior work with regional tropical cyclone models. On the other hand, there is a tendency toward increased frequency of events in the western North Pacific.
...global power dissipation increases somewhat more than that over the next 200 yr in simulations driven by climate models undergoing global warming. This suggests either that the greater part of the large global increase in power dissipation over the past 27 yr cannot be ascribed to global warming, or that there is some systematic deficiency in our technique or in global models that leads to the underprediction of the response of tropical cyclones to global warming. (emphasis mine).
Emmanuel is getting praise from all sides for his willingness to follow the data where they lead. Once he was the go-to guy for the notion that global warming is making hurricanes worse. Three years later, he's the one warning that may not be true. Roger Pielke Jr. calls him a "great scientist." That he is. It's not every day that a scientist achieves fame by casting doubt. Shedding light is the more common method. But that's science for you.
Aside from reputation building, the real story here ;;;;; and the one that will almost certainly be twisted out of all recognition by the usual suspects ;;;;; is not that the consensus on anthropogenic global warming (AGW) is weaker. As Houston Chronicle reporter Eric Berger notes in a blog post in support of his story on the paper:
If you're a skeptic, and you welcome these results, please remember that these are the same climate models you bash when they show global temperatures steadily rising during the next century.
In other words, if you don't buy the prevailing consensus, then you can't embrace Emmanuel's new findings to support your objection to the consensus. But then, the entire anti-AGW community is characterized by cognitive dissonance.
I'll leave the last word to Andy Revkin, whose blog post covers all the relevant points:
...somehow society has to learn how to be comfortable with this aspect of the scientific enterprise, while not fuzzing out because things aren't crystal clear. As Stephen Schneider, a veteran climatologist at Stanford, recently mused, the question is, "Can democracy survive complexity?"
It's clear that Dr. Emanuel's admonition about the need for a lot more work applies beyond the realm of science, as well.
Emanuel, K., Sundararajan, R., Williams, J. (2008). Hurricanes and Global Warming: Results from Downscaling IPCC AR4 Simulations. Bulletin of the American Meteorological Society, 89(3), 347. DOI: 10.1175/BAMS-89-3-347
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"...or that there is some systematic deficiency in our technique or in global models that leads to the underprediction of the response of tropical cyclones to global warming."
I find it ironic that you now feel the need to emphasize the uncertainty in climate models only when the latest data doesn't support your alarmist rhetoric.
When those of us that have noted the failure of these computer "projections" to predict actual climate conditions have made statements like this you are quick to call us names like "denialist".
Whose the denialist now?
I also love this bit of twisted illogic.
Lance: read the post and the paper again. All I'm saying is: if you embrace the conclusions of Emmanuel's latest research, then you are saying that the climate models are good, at least as far as global warming goes, because his research uses models that say the Earth is warming due to greenhouse gases.
Since when do I have to embrace the premise of your argument to see that it is self-inconsistent?
You rely upon climate models to say that we face anthropogenic global warming. Then you make dire predictions based on this alleged warming (i.e. more frequent and stronger hurricanes). Then, embarrassingly, using these same models this claim is refuted.
Your argument just evaporated of its own accord. I needn't believe its premise to point that out. If you claim that the models were wrong to recover your claim that we face more frequent and stronger tropical storms then you have lost your premise that supports the idea of anthropogenic climate change.
Lance is unaware that Emanuel's prior results are not based on GCMs. Also, there's at least one major forthcoming revision to the models (based on observations) that could change the new results substantially. Finally, there are very strong theoretical grounds for believing that over the very long-term (more than 200 years) TC activity will be enhanced considerably.
Excuse me Mr. Bloom but I am quite aware of Kerry Emanuel's previous work and never stated that it was based on GCMs. His earlier work is hotly contested by Landsea and others who point out the tenuous nature of his "observational" data.
As for your assertion that "...there are very strong theoretical grounds for believing that over the very long-term (more than 200 years) TC activity will be enhanced considerably." That is overstating the issue in your favor, something for which you have demonstrated a great propensity.
There is ample "theoretical grounds" that temperature gradients will be less dynamic in a warmer world which lessens both the likelihood and severity of storms, and that the conditions for vertical wind shear, a factor that mitigates tropical storm formation, will also increase.