Bishop Hill writes:
Over at Climate Audit, Nic Lewis has outlined the latest developments in the saga of the Marvel et al paper, which claimed to have demonstrated that climate sensitivity is low, but appeared to have a whole series of problems, not least of which that it had got its forcing data mucked up, leaving out land-use changes entirely.
In a typically erm…robust article at RealClimate, Gavin Schmidt ignored all the evidence Lewis had presented showing that land-use change had been overlooked, and said that Lewis’s critique was made…without evidence. However, it now seems that he has decided that this position is not tenable, at the journal at least,and a correction has been issued admitting that land-use was indeed missing.
The historical instantaneous radiative forcing time series was also updated to reflect land use change, which was inadvertently excluded from the forcing originally calculated from ref. 22.
Gavin has thanked Nic Lewis for pointing out the error. Unfortunately, he has chosen to ignore four other problems that Lewis has has pointed out.
But hey, one out of five ain’t bad.
Here’s the list of problems:
Lewis enumerates 6 supposedly fundamental problems in the paper. To paraphrase, they are as follows:
- MEA15 is working with the wrong definition of climate sensitivity.
- All previous papers using the historical records to constrain ECS are only constraining ‘effective’ climate sensitivity which is smaller than ECS.
- MEA15 used the wrong iRF and ERF values for F2xCO2.
- MEA15 shouldn’t have used ocean heat content data (or should have done so differently).
- The regressions in MEA15 in the iRF case should have been forced to go through zero.
- The linearity of the different forcings is only approximate.
It’s quite something, really, that time and again climate skeptics are the ones who find the problems at NASA GISS and the “experts” don’t. Maybe Gavin should spend less time bloviating about his background, doing PR outreach, or running from debate, and more time being a real climate scientist.