With regards to the recent US Supreme Court decision describing carbon dioxide as a pollutant and requiring the EPA to again look into regulating it, it turns out that there is a fascinating side issue into what claims greenhouse denialists are actually prepared to make when their claims will be thoroughly scrutinized.
A group of denialists hazily associated with the Competitive Enterprise Institute, (the organization responsible for the unintentionally hilarious CO2 – We Call It Life advertisements) and including Patrick Michaels (who can’t tell the difference between degrees and radians), and Chris de Freitas (who publishes papers without telling his peer-reviewers), put together an amicus curiae brief in support of the EPA’s position not to regulate CO2 emissions.
Professor Ian Enting, from the University of Melbourne, was one of the lead authors of the Chapter “CO2 and the carbon Cycle” in the 1994 IPCC Report in Radiative Forcing of Climate. He has provided me with an excerpt from his forthcoming book “Why Greenhouse Denial Isn’t Science”. As he explains, it’s fascinating not so much for what it says, but what it’s not prepared to say…
In the form brought to the Supreme Court, the state of Massachussetts and others were seeking remedy from the US Federal Environmental Protection Agency (EPA) for its failure to act certain greenhouse gas emissions. As part of this process, with the permission of the court, various Amici Curiae (friends of court) briefs were lodged, one by a group of climate scientists (in support of the plaintiffs — Massachussetts) and by a group of climatologists and scientists (in support of the respondents — the EPA). In this book, this latter brief will be termed “the sceptics’ brief” and is examined in this section. Those named as the climatologists and scientists in the sceptics’ brief were Sallie Balinas, John R. Christy, Chris de Freitas, David Legates, Anthony Lupo, Patrick Michaels, Joel Schwartz and Roy W. Spencer, with counsel from the Competitive Enterprise Institute.
In the context of the `pretend debate’ about the reality of human-induced climate change, the sceptics’ brief, like the case as a whole, is most remarkable for what was not said. With the prospect of having their views tested in court, the brief differed greatly from their various statements in the media.
The sceptics’ brief emphasised the uncertainties in the issue, particularly with respect to net costs. The effect of this on the case would seem to have been reduced by the failure of the respondents (EPA) to invoke this argument. Issues of complexity were noted in a dissenting opinion. Perhaps the greatest departure from earlier sceptics’ positions is the statement
A far better estimate of future warming comes by reconciling climate model projections of the future with real-life data — that is, with the known historical behaviour of climate as greenhouse gases have increased. This is because models are more plausible when they are in agreement with actual observations. As is shown below, the expected warming from such increases then becomes 1.8 degrees Celsius for this century, which is clearly below the low end of the National Assessment’s range.
If you look at the summary for policymakers from the latest IPCC assessment report, 1.8 degrees isn’t all that different to the IPCC’s various warming scenarios – as best I can tell, the “A1B” scenario best represents the “business as usual” scenario. 1.8 degrees is below the IPCC’s expected value, but it’s within the confidence interval.