Dessler: "What matters is that this mole hill will be blown up to a mountain by advocates who want to use this difference to launch attacks on the IPCC."

Yep. And it looks like one of the usual suspects is launching a preemptive strike.

Benny Big Eye

Andrew, AFAIK the IPCC doesn't have a category that can be used to reflect something like a 51% likelihood.  Unless a new category has been invented, all they have is "as likely as not" for 33% to 66%, moving up to "likely" for 66% to 90%.  There is no "more likely than not" as quoted in the AP story.    

Steve-

You're correct.  Footnote 7 of the TAR WGI SPM did not list anything like that.  On the other hand, "more likely than not" has a reasonably simple interpretation --- more so than words such as "likely".  I'll be quite interested to see what actually comes out in the report.

Sure enough, they added a couple categories and changed the ranges, as would make sense in order to reflect finer-grained results.

Virtually certain > 99% probability of occurrence,
Extremely likely > 95%,
Very likely > 90%,
Likely > 66%,
More likely than not > 50%,
Unlikely < 33%,
Very unlikely < 10%,
Extremely unlikely < 5%

Hmm, "less likely" seems to be missing in action.  Maybe they don't use it anywhere.  

I attended the biennial Galveston Bay conference last week and saw a great presentation by one of your collegues, Jennifer Irish.  Basically it floored everyone.  The gist was that hurricane intensity (max. sustained winds) maybe a poor way of gaging storm strength and subsequent damage.  Rather, storm size (distance from eye to area of max. winds) and wind speed are a better indicator of storm surge (the most damaging aspect of the storm) height.  Katrina and Rita, a category 3 and barely a 2, were very large, intense storms, fueled by passage over warm loop currents in the Gulf, which radically dropped in wind speed during eye wall replacement cycles and increasing shear.  Turns out the drops in wind speed did little to reduce their storm surge and destruction.  I think when the NOAA and AMS folks state that AGW's effect on storm intensity is unknown, they are doing so knowing that max. wind speed is a tricky thing to predict and isn't essentially tied to sea surface temps.  However, it turns out that AGW caused increases in storm size and subsequent damage maybe more easy to predict using sea surface temp changes.  More work needs to be done investigating how AGW will effect Gulf loop currents, etc.  Any thoughts?

Lastly, Larry Soward, the commissioner of the Texas Council on Environmental Quality (our air and water quality agency) and the govenor's former chief of staff, gave the closing address.  Started out normal, great job everyone etc., and then suddenly it seemed like he dropped his notes and went on a tear about how there is no downside to the reduction of green house gases.  He discussed the adverse effects of climate change and rising seas on Texas very eloquently.  The conference gave him a spontaneous standing ovation.  Afterwards I learned it was the first time he gave this address.  This is the agency that will have to approve new coal fired power plants in Texas.

Andrew Sipocz

That's quite interesting about Soward. Do you know if his address was recorded?

www.grist.org

I don't believe so, neither were the press present.  It was an astounding pronouncement.  We'll have to see what happens when the agency he heads reviews the dozen or so coal-fired power plants that TXU wants to build.

Andrew Sipocz

We need good news!  Very encouraging.  We should all remember Texas also has a lot of progressive reform minded citizens.  I forget that too from time to time.

Texas is number one in wind power, I think?  In growth and installed capacity.

http://amazngdrx.blogharbor.com/blog

Hi Andrew,

Could i ask you to put me on the right track here, since i'm discussing global warming and hurricanes in another forum.

The trouble i'm having is to define which statements that are acceptable in light of the WMO and/or the IPCC consensus. I'll use Katrina here as an example - but this really isn't about it. The discussion boils down to these two statements:
Katrina was caused by global warming
Katrina was not caused by global warming

From my personal reading both of these two statements are wrong. I know that its not possible to pin down the attribution in intensity to a single event, and i'm also well aware that the AMO probably has a much larger impact on north atlantic cyclones, and that land-use changes and development is the real culprit in the damages from hurricanes (both for Katrina and in general), since i do read prometheus once in a while...

Hopefully you can help me in assessing whether i'm correct or entirely off track in this. I don't mind being wrong - i'd rather correct any mistakes that i've made.

Thank you,

Kim.

Kim-

It is impossible to attribute (at least with our current knowledge) any single event to global warming.  Ditto for saying that global warming had no effect on any single event.  

So, as you surmised, both statements are wrong: we cannot say what effect global warming had on Katrina.  

What can you say?  From the IPCC: Based on a range of models, it is likely that future tropical cyclones (typhoons and hurricanes) will become more intense, with larger peak wind speeds and more heavy precipitation associated with ongoing increases of tropical SSTs.