A recent comment here brought up the frequent contrarian argument that there is a signature patern to enhanced greenhouse gas warming that is missing in the observational data despite showing up in the models. This is notably absent from the How to talk to a climate sceptic guide, something I hope to rectify Real Soon Now(tm).
I left a comment response but thought I may as well put it here in a new thread as it is OT over there.
Here is the referenced graph:
Figure 9.1. Zonal mean atmospheric temperature change from 1890 to 1999 (Â°C per century) as simulated by the PCM model from (a) solar forcing, (b) volcanoes, (c) wellmixed
greenhouse gases, (d) tropospheric and stratospheric ozone changes, (e) direct sulphate aerosol forcing and (f) the sum of all forcings. Plot is from 1,000 hPa to 10 hPa
(shown on left scale) and from 0 km to 30 km (shown on right). See Appendix 9.C for additional information. Based on Santer et al. (2003a).
My response was this:
I had a look at your AR4 link (AR4WG1_Print_Ch09.pdf) and the graphs you referenced. I think you, or the site your are getting this from, are misinterpreting them. They show six images, one for each of solar, volcanic, GHG, ozone, sulphates and all forcings, images of the zonal warming by height in the atmosphere.
I believe that these are produced using the observed forcings, and therefore are not what we would expect to see if, for example, all of the recent warming were from solar, or all from ozone etc. So you can not take the observed warming pattern and meaningfully compare it to any one of the individual forcing graphs.
For a comparison of solar forcing vs CO2 forcing of equal and large magnitudes see this Real Climate article and the graphs in that.
I think that the real signature of an enhanced greenhouse is a cooling stratosphere, and this observation is much clearer than the observations of only mild warming in the tropical troposphere (findings of which are already being contradicted).
While we are all talking about patterns of warming, doesn’t the stratospheric cooling strike any of the denialist websites as requiring some explanation? Because that is the real signature of an enhanced greenhouse effect, and on that point the observations and the models are in very strong agreement.