Yet another ‘consensus’ document

People send me things from time to time, with the explicit or implicit suggestion that reading whatever it is will change my views on whatever it is about. Sometimes they are scientific papers. More often they are appeals, claims, expressions of outrage, or a combination of all three. They are intended for the broader public, and usually for ‘policymakers’ — meaning politicians.

Professor Lowe’s speech to the National Press Club, to which I devoted my last two posts, is an example. Hot on its heels comes another, entitled ‘Scientific Consensus on Maintaining Humanity’s Life Support Systems in the 21st Century. Information for Policy Makers’, and you can read it here. The statement seems to have started at Stanford University in California with the assistance, or perhaps prodding, of Governor Jerry Brown. The document I read has 520 signatures, but the website suggests that there are now more than 1700. More about all that in a moment.

The executive summary starts with the following call to action: ‘Earth is rapidly approaching a tipping point. Human activities are causing alarming levels of harm to our planet.’ Let’s stop there a moment. ‘Tipping point’ is a metaphor widely used by global warming alarmists. It suggests unstoppable, runaway processes, which must be prevented by the concerted action sought in the document. I did some work  on ‘tipping points’ a few years ago, and couldn’t find any evidence of them. They are conjectures, based on the fact that glaciations come and go, and something must start them and end them, and the shift seems to take place pretty quickly, in geological time scales. I’ll go back and see if anything more has appeared in the literature since then. If it has, I’ll do a post on it.

Then come five ‘human impacts of key concern’. The first is ‘climate disruption’, a relatively new term used because ‘global warming’ doesn’t resonate any more, perhaps because warming has paused: ‘more, faster climate change than since humans first became a species’. The text later in the document doesn’t mention at all that there is no evidence to link extreme weather events to increased temperature, or that temperature has paused, or that the projections for the future are based on models that have neither been validated nor shown to be good predictors of temperature. The examples it gives of the Sandy storm in New York, floods in Australia, and fires in Australia and the USA, are neither extreme in historic terms nor causally linked to temperature (which has paused …). And there is tons of evidence for all that. Why is not mentioned? It would get in the way of the shock-horror predictions for the fate of humanity unless something is done now, I guess.

Species extinction is the next awful cab off the rank, and there are claims of extreme kinds about what is actually happening, and will happen unless, again, something is done right now to prevent it. This is not an area that I have done much work on, but I did comment on a cool account of extinction back in January. The actual corpses of the extinct are somewhat hard to produce, even if it is true (which I doubt) that ‘the most conservative analyses indicate that human-caused extinction of other species is now proceeding at rates that are 3-80 times faster than the extinction rate that prevailed before people were abundant on Earth’. And viruses and insects seem to be doing well, no matter how hard we try to diminish their number and their effect on us.

Enough! Why do people put out such unbalanced stuff? Well, it is intended to be a call to action, by people who really care, so they are not much interested in a balanced account of our situation. And are there politicians who will fall for it? Well, yes there are, and one of them is close to us. This is what our Prime Minister said the other day in response to a Dorothy Dixer from Independent Rob Oakeshott, MP: ‘I absolutely accept the science [of climate change] and do not believe that it is possible for a person of reason to have any other view’. There you go. Ms Gillard probably thinks that this document embodies  the science of climate change, and of course it does, but not all of that science, by any means.

You probably want to know something about the signatories. Well they include such notably balanced climate scientists as James Hansen, Peter Gleick, Michael Mann and David Suzuki, and in our part of the world, David Karoly, and Lesley Hughes of the Climate Commission. The interesting signatory for me is Kenneth Arrow, Nobel Laureate in Economics in 1972, and the originator of the impossibility theorem named after him, and much else besides that I worked on as a graduate student in the 1960s and thereafter. I hadn’t known that he had been a lead author for one of the IPCC Reports. Indeed, I hadn’t known that he was still alive (he’s 92 and an emeritus professor at Stanford).

When you come across a statement like ‘the vast majority of scientists … agree’ your best action is to move on. Appeals to consensus only suggest that as a reader you are not allowed to make up your own mind. In the field of global warming, as I have said many times, the core propositions are straightforward, and any reasonably interested and educated lay person can get to understand what they are quite quickly. There’s a lot of hard slog if you want to go much further. But consensus is such a weak weapon to enter public debate with. That is being used so frequently now suggests to me a level of desperation on the part of the users.