My thanks to Ned Nikolov, who has alerted me to a new paper by Ben Santer et al entitled ‘Identifying human influences on atmospheric temperature’. The co-author list reads like a who’s who of the senior echelon of the IPCC warmers: Susan Solomon, Tom Wigley, Julie Arblaster and Peter Stott, to name a few among them.
So what do the climate Cluesos have to tell us this time? Have they now successfully identified a human influence on the climate system? The Fun thing about the title is that it is immediately contradicted by the abstract, in which we find this telling passage:
We use simulation output from 20 climate models participating in phase 5 of the Coupled Model Intercomparison Project. This multimodel archive provides estimates of the signal pattern in response to combined anthropogenic and natural external forcing (the finger- print) and the noise of internally generated variability. Using these estimates, we calculate signal-to-noise (S/N) ratios to quantify the strength of the fingerprint in the observations relative to fingerprint strength in natural climate noise.
Watch the pea, very, very carefully.
First of all, notice the interesting new twist on the use of “finger-print“. Previously, this non-scientific term has been employed to refer to the non-appearing tropical tropospheric ‘hotspot’ as the ‘finger-print of anthropogenic global warming’. But now, apparently, it refers to “combined anthropogenic and natural external forcing”. So this term, ‘finger-print‘ implying as it does a unique and specifically human identity, now refers to a putative human influence and solar/cosmic influence lumped together. What kind of ‘fingerprint’ is that?
The main bone of contention in the climate debate is the question of whether the late 20th century warming was predominantly caused by the more active than average Sun, some longer term modes of internal variability, or by increasing human emission of carbon dioxide. Now the ‘Team’ is trying to conflate the solar influence with human influence and contrast these two entirely different factors with internal natural variability, which they call ‘noise’.
Do they think no-one will notice this less than adroit reframing of the climate question which now leaves the main issue wide open? Following this conflation of natural and human influence, will they really continue to tell us that they are still of the opinion that it is ‘very likely’ that human emission of carbon dioxide is responsible for more than half of the (gentle and beneficial) warming of the Earth’s atmosphere (and oceans) since around 1979? Speaking of the oceans, you’ll notice that they don’t speak of the oceans. The title and abstract refers only to the atmosphere. This is a tacit admission by omission – back radiation can’t heat oceans. But something did. That would be the Sun then. At the end of the abstract we get this:
On average, the models analyzed underestimate the observed cooling of the lower stratosphere and overestimate the warming of the troposphere. Although the precise causes of such differences are unclear, model biases in lower stratospheric temperature trends are likely to be reduced by more realistic treatment of stratospheric ozone depletion and volcanic aerosol forcing.
In my opinion they’d be reduced by a lot more if they faced the fact that solar variation has a much bigger effect on stratospheric ozone levels than anything man gets up to. But once again, we see that the Sun has been elbowed out of consideration, it’s all about volcanoes and atmospheric ‘greenhouse gases’. On the upside, there is now top-tier acknowledgement that the models have overestimated tropospheric warming. Unfortunately, there is little indication that the climate Cluesos are going to pick up the trail of the real warming culprit looking at any ‘finger-prints‘ through their distorted and dusty magnifying glass.