Blog Archive

Monday, January 20, 2014

Eli Rabett: Curry vs. Curry

by Eli Rabett, "Rabett Run," January 20, 2014

Dana NuccitelliAnd ThenSou and Bart have comments on last week's Senate Environmental and Public Works Committee testimony by Prof Andy Dessler and Prof. Judith Curry.

Prof. Curry has issued a challenge to those (Mike Mann usw) who think she was being economical with the truth:
Since you have publicly accused my Congressional testimony of being ‘anti-science,’  I expect you to (publicly) document and rebut any statement in my testimony that is factually inaccurate or where my conclusions are not supported by the evidence that I provide.
Now some, not Eli to be sure, might point out that there is more than a bit of lawerly verbage in there given the cherry orchard that the evidence that somebunny provides can omit, but the bunnies are forgiving beasts.

In Prof. Judith Curry's testimony she claimed that

However, several key elements of the AR5 WGI report point to a weakening of the case for attributing most of the warming to human influences, relative to the previous assessment
  • Lack of warming since 1998 and the growing discrepancies between observations and climate model projections
  • Evidence of decreased climate sensitivity to increases in atmospheric CO2 concentrations
  • Evidence that sea level rise during 1920-1950 is of the same magnitude as in 1993-2012
  • Increasing Antarctic sea ice extent
Permit the Rabett to start at the bottom.  Eli and the Weasel previously noted Prof. Curry really does not believe that increasing Antarctic sea ice extent casts any doubt on the AR5's conclusions because she knows why the sea ice in Antarctica has been increasing (or perhaps not increasing as much, that may be another interesting tale of whom do you believe, theory or observation, as a recent preprint casts doubt on the magnitude).  In a 2010 PNAS paper, "Accelerated warming of the Southern Ocean and its impacts on the hydrological cycle and sea ice" Prof. Curry's abstract reads: 
The observed sea surface temperature in the Southern Ocean shows a substantial warming trend for the second half of the 20th century. Associated with the warming, there has been an enhanced atmospheric hydrological cycle in the Southern Ocean that results in an increase of the Antarctic sea ice for the past three decades through the reduced upward ocean heat transport and increased snowfall. The simulated sea surface temperature variability from two global coupled climate models for the second half of the 20th century is dominated by natural internal variability associated with the Antarctic Oscillation, suggesting that the models’ internal variability is too strongleading to a response to anthropogenic forcing that is too weak. With increased loading of greenhouse gases in the atmosphere through the 21st century, the models show an accelerated warming in the Southern Ocean, and indicate that anthropogenic forcing exceeds natural internal variability. The increased heating from below (ocean) and above (atmosphere) and increased liquid precipitation associated with the enhanced hydrological cycle results in a projected decline of the Antarctic sea ice. (emphasis added)
Of course the Weasel thinks the entire paper is the stadium wave in forecasting form, but Eli will be generous given that Prof. Curry thinks that the paper was a good thing given her comments over at Stoat's. (The paper has vanished from the Ga Tech cache btw.)  OTOH, a forecast of growth of sea ice through increased snow fall has a pretty simple and obvious mechanism going back to at least the 1990s.  The range of temperature at which snow falls is rather small basically because there has to be a significant amount of water vapor in the atmosphere, and when it gets really cold there ain't, so the only way for snow to fall is transport from warmer areas.  This makes sense if the Southern Ocean is warming, which cannot be gainsaid (Skeptical Science has two useful debunkers which demystify Prof. Curry's claim in depth from which the next two images are borrowed):

and, of course, while there may be more sea ice, Antarctica itself is losing mass at a furious rate due to warming

But perhaps Prof. Curry's position has now shifted to that enunciated by Mark B:
Liu and Curry, defended by The Team, selected inappropriate data and time periods, ignored data that doesn’t match the IPCC message, manipulated results, clearly engaged in misconduct, dismissed dissenting views, and ultimately pushed the notion that Antarctic Sea Ice will melt, based on fudged computer models, when data clearly shows otherwise. Read ‘The Antarctic Ice Illusion: CurryGate and the Corruption of Science’ by Montfork. It’s one of the best books written on climate science, though I can’t personally vouch for any of its conclusions.
Prof. Curry appears to have publicly documented and rebutted Prof. Curry's statement in Prof. Curry's testimony about Antarctic sea ice increase weakening the evidence for man made climate change. Many thanks.

While Antarctic sea ice increase is taking place, according to Prof. Curry, it is inaccurate to say that it is evidence against man-caused climate change, but according to her own published work, and that of others dating back to decades before her work, it is actually evidence for man-made climate change because of the forecast increase in snow fall. Prof. Curry's own work contradicts her own testimony.  Bunnies can now debate to what extent she gets an out by demanding that such a demystification be limited to the evidence that Prof. Curry provided, given that Prof. Curry probably provided Prof. Curry's CV with a list of publications as part of the evidence.  Moreover, this appears to be another case of where the models are too optimistic, as Prof. Curry herself states in Prof. Curry's paper.

To paraphrase Richard Alley: Prof. Curry looks at one part of the data, ignores much and and advises nulo problemo; Prof. Dessler looks at the entire picture and says, hey the models tell us we got a problem, we need to do something quick, and the Earth is over in the corner screaming bloody murder.

Comments hilarious:
Joshua said...
I think that you're missing a key point. The Professor Curry who wrote that paper is not an activist - in fact she thinks that scientists being activists is undermines science. The Professor Curry who testified before Congress is an activist, who appeared at the behest of Republican politicians so as to boost the viability of the policies they support. And don't forget that the Professor Curry who blogs strongly opposes any appeal to authority, whereas the Professor Curry who is making highly public statements about climate change feels that it is important for Professor Curry to lend her qualifications and professional recognition to the cause of climate "skepticism."

I hope that clears things up a bit.
EliRabett said...
Eli's head is spinning.

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