Tuesday, March 24, 2015

Ringberg 2015: Andy Dessler ECS > 2K and more

POSTSCRIPT:  The presentation slides for all the talks are now posted and Gavin has a post on Real Climate

Andy Dessler posted his Ringberg 2015 talk on climate sensitivity.


Fernando Leanme said...

It reminds me of the essay "How to inflate a life jacket using a vacuum bottle".

Arthur said...

Hey, he uses a reference no-feedbacks "Planck" response at constant relative humidity, rather than constant temperature change! That's something I thought was absolutely needed, I didn't realize it had been seriously done. Excellent! Basically with that definition, no-feedbacks sensitivity is 2 K to doubling, which is the main point that comes out of his argument.

BBD said...

Good for AD, although it's a shame that he's had to keep repeating increasingly sophisticated versions of this message for so long.

Since paleoclimate basically doesn't work unless ECS is at least ~2C there should be no need to labour this point. Central estimates of ECS below 2C can be presumed to be wrong.

* * *

Nobody cares what you think, Fernando.

KAP said...

Referring back to an earlier comment I made on a thread from a few days ago, if you regress surface temperature to lagged ln(CO2), the slope of that line gives you ECS directly as 3.1, right in line with the result here by Andy.


Mulitply the slope, 451, by ln(2) (because we're doubling CO2) to give 311. Since GISS temperture is measured in hundredths of a degree, that's 3.11 C per doubling.

Andrew Dessler said...

Arthur: Yes, the constant RH framework is vastly superior to the standard decomposition. See Held, I., and K. M. Shell (2012), Using relative humidity as a state variable in climate feedback analysis, J. Climate, 25, 2578-2582, doi: 10.1175/JCLI-D-11-00721.1 for a detailed discussion.