How do climate scientists explain the ‘pause’ (‘hiatus’)?

Anthony Watts says that the number of explanations for the ”pause’ in global warming has now reached 52, one for each week in the year. I used inverted commas to signify that no one knows whether it is a pause or simply a cessation, and no one knows how long it will last. There are two main views: one is that the warming will (soon) resume with a vengeance, and the other is that we’re in for a decade or two of cooling. I think we are allowed to take our pick, and in fact my pick is that I don’t know, and wait to see. Nature will tell us all in time.

Well, it is claimed that excuse #53 has arrived, and in The Conversation, a website about which I feel less than gruntled, given that while it is about universities and proclaims academic rigour it seems to me to be largely an excuse for academics to portray their opinions as science. The piece in question is by a British academic, Professor Rob MacKenzie of the University of Birmingham, and is a bit of a puzzle. You can read it here.

My guess is that it was originally written for a British newspaper or website, because its main focus is on the recent trenchant speech by Owen Paterson, the former UK Secretary of State for Environment, about ‘the Green blob’ — the network of NGOs, sympathetic politicians, businesses and believers who keep the UK in a more and more desperate and increasingly futile search for alternative energy sources that will replace coal-fired and nuclear power stations, at great expense to the British taxpayer.

The headline is probably not the author’s, and it proclaims Climate change: it’s only human to exaggerate, but science itself does not. What does that mean, you ask. The author goes on to explain: To exaggerate is human, and scientists are human. Exaggeration and the complementary art of simplification are the basic rhetorical tools of human intercourse. So yes, scientists do exaggerate. So do politicians, perhaps even when, as the UK’s former environment secretary Owen Paterson did, they claim that climate change forecasts are “widely exaggerated”.

What exactly did Paterson say? The sentence in which this phrase occurs goes: I also note that the forecast effects of climate change have been consistently and widely exaggerated thus far. Well, there can hardly be any doubt that the forecasts of catastrophe have been very widely made, from the UN and  within and across all continents. Exaggerated? It depends on what you mean, doesn’t it. Paterson gives examples: The stopping of the Gulf Stream, the worsening of hurricanes, the retreat of Antarctic sea ice, the increase of malaria, the claim by UNEP that we would see 50m climate refugees before now – these were all predictions that proved wrong. I could add a few of Professor Flannery’s forecasts made about Australia.

As it happens, he is absolutely right about the UNEP claim, made in 2005 for 2010. It has disappeared from the UNEP website, but available everywhere by just searching for ‘UNEP fifty million climate refugees’. Paterson’s speech is worth reading — well-written, accessible and a summary of what I would think is the current sceptical wisdom of the possibility of replacing fossil fuels by alternative energy sources anywhere in the next fifty years.

Back to Professor Mackenzie. He argues that when scientists become advocates they are as prone  as anyone else, especially politicians, to use whatever rhetorical devices they have to win an argument. I would agree with that. But that isn’t the case, he says, when scientists use their own very special form of mass media, the peer-reviewed literature. There they are cautious. Yes, I would agree again, but the PR departments of their universities are always looking for a good story, and are prone to sex up the implications of an abstract in their media release, in the hope that a major newspaper will pick it up.

MacKenzie argues that another worry is ‘simplification’, which occurs when scientists have to talk to a lay audience. He’s right there, too. And then he sums it up this way: Scientists, wandering unwarily into the realm of advocacy, may be guilty of taking the results out of context, as may be activists and politicians, but it is not the science itself that is “widely exaggerated”… As a taxpayer I would like to believe that physical and computer models provide evidence to politicians who use it to assess the strength of the arguments of the various advocacy groups. 

Speaking as another taxpayer I would hope that our politicians do not ever accept that physical and computer models provide ‘evidence’. Model runs are model runs. Evidence comes from observation and experimentation. His last paragraph is a shaft directly aimed at Paterson: I do hope, though, that claims of scientific exaggeration are seen for what they are: advocacy targeted not just at winning the rhetorical argument but also aimed, rather cynically, at undermining the evidence.

I said this article is a puzzle. In my view it is self-contradictory in parts. Does it rank as excuse #53 for the pause in global warming? I don’t think so, though I can see how you could make the case. Professor Mackenzie, for all his wisdom about rhetoric and peer review, turns out, in that last paragraph, to be yet another believer in AGW. Of what evidence is he thinking? UK energy policy is not based on evidence, but on models, alarmism and belief. If it were based on evidence it would have been altered ages ago.