Complaint to Ofcom Regarding “The Great Global Warming Swindle”

So for example the estimate in the IPCC’s 2007 report that the global mean temperature is likely to rise by between 1.1C-6.4C this century with a “best guess” of 3C (http://tinyurl.com/2xl4c6, PDF) is not a forecast: it represents a range of scenarios such as those described above; and much of the uncertainty is due to uncertainty about human behaviour, not uncertainty about climate science.

An authoritative example of the use of these scenarios is the IPCC Special Report on Emissions Scenarios (SRES) (http://tinyurl.com/3co3n3). The SRES included a set of four alternative “families” of future scenarios for industrial activity (and greenhouse gas emissions). These families were characterised by population, technological development, economic growth, and environmental outlook. These characteristics all are highly uncertain for the future, and would all change how the climate would appear. The IPCC stresses that the SRES scenarios are not predictions or forecasts – see http://tinyurl.com/2lhfvu.

The film maker should have been aware of all this, as it is all publicly available information; and most of the contributors to the programme were certainly aware of it. Thus this section of the Channel 4 programme was an apparent attempt to mislead the viewer in order to promote an agenda, and was a betrayal of the public’s trust.]

(In breach of the 2003 Communications Act Section 265, Ofcom 5.4, 5.5, 5.7, 5.11, 5.12)

[Comment 93: It is not true that the IPCC has overestimated the CO₂ increases that have occurred in the last thirty years – see Figure 1 of the Proceedings of the National Academy of Sciences of the United States of America, at http://tinyurl.com/2d7uwu (PDF).

Furthermore, models do not predict more warming than is occurring: they match the observations well. For example, models driven with historical changes in CO₂ and other factors accurately “hindcast” temperatures over the past century (http://tinyurl.com/2v4x2t [IPCC 2001]), and a 1980s NASA climate model accurately predicted the temperature increases over the past two decades (http://tinyurl.com/29e53y [RealClimate]). Climate projections are made for a variety of scenarios, which reflect uncertainties in future emissions of CO₂ and other pollutants, not just the 1% per annum increase implied by Michaels (see Comment 92, above).]

(In breach of Ofcom 5.7)