In several recent posts, we’ve been reviewing the provenance of the radiative forcing estimate of about 4 wm-2 and the logarithmic form for estimating climate response to increased CO2 levels. This has led on the one hand to several primary references, including Lacis et al 1981 and, on the other hand, to references to realclimate […]
Over the last week or so, I’ve reported on my efforts to locate the provenance of the functional forms for the relationship between levels of CO2 and other greenhouse gases and temperature. Lubo has also chipped in on the topic from a different perspective proposing a derivation of a log formula from first principles. We’ve […]
David Holland has written in raising an excellent point about the failure of IPCC WG1 to release the Review Editor comments. In our examination of specific issues e.g. the Briffa truncation, the handling of trends, etc., the Author Responses (online through an earlier CA initiative) show that the IPCC authors often made unconvincing and tendentious […]
Yesterday I collated IPCC AR3 and AR4 “expositions” of the enhanced greenhouse effect, observing that, in my opinion, they were so baby food as to be essentially useless to a scientist from another discipline. Today I’m going to drill a little deeper in the expositions, going to a 1995 journal comment by Houghton and to […]
One of the fundamental questions for someone interested in the impact of doubled CO2 is exactly how (1) the greenhouse effect works; and (2) how the “enhanced” greenhouse effect works. AR4 FAQ 3.1 poses the question: I’m going to show their answer to this question in full because the answer does not rise about a […]
In our summary of IPCC AR1 (1990) on radiative forcing, I noted that the logarithmic relationship and 4 wm-2 values were attributed to: Hansen et al (1988), which in turn cited Lacis et al 1981; and Wigley (1987) which is not presently available to me (or to Wigley himself) and appears not to have been […]
AR4 (chapter 1 on the History of Climate Science) contains the remarkable statement: The strong effect of cloud processes on climate model sensitivities to greenhouse gases was emphasized further through a now-classic set of General Circulation Model (GCM) experiments, carried out by Senior and Mitchell (1993). They produced global average surface temperature changes (due to […]
It is very difficult for the general public to understand that IPCC does not carry out independent due diligence. The answers of Michael Mann in 2003 to questions from Sen Inhofe are well worth re-reading in the present context. Mann says that it is “against the mission” of IPCC to “carry out independent programs” or […]
As an innocent bystander to the climate debates a couple of years ago, I presumed that IPCC would provide a clear exposition of how doubled CO2 actually leads to 2.5-3 deg C. The exposition might involve considerable detail on infra-red radiation since that’s relevant to the problem, but I presumed that they would provide a […]
Michael Smith asks: Since we are discussing uncertainty intervals, I have a question — probably a dumb one, but what the heck. In the Summary for Policy Makers, IPCC 4th AR, there is a graph “Figure SPM.1” on page 3. See here: http://www.ipcc.ch/pdf/assessment-report/ar4/syr/ar4_syr_spm.pdf The graph show “Global average surface temperature” since 1850. It includes individual […]
Climate Audit 