I have mentioned Judith Curry and her website Climate etc many times, and I am deeply impressed both with what she does there, and with her capacity to represent her perspective on ‘climate change’ in the public arena and especially to government. She is a senior and well-published scientist in the climate area, and you can read about her, and about her work, here. Her most recent foray in the public domain I’ll come to in a moment.
But first I want to say something about the kind of arena that she encounters in the USA. There, it is fair to say, ‘climate change’ is something that has a sharp partisan divide. Serious Republicans generally think that ‘catastrophic’ anthropogenic global warming (CAGW) is just about a hoax, or at the very least hopelessly exaggerated. Serious Democrats take the opposite view, from the President down. Most Americans, according to Gallup, don’t think the issue is important at all.
And because Congress has lots of committees, and the committees like to call witnesses, there have been a number of occasions when scientists of a sceptical bent have been asked to give evidence. That could happen here, too, but our committee system is different, and it is preoccupied with what the current Government is doing, or not doing. And our committees rarely call for witnesses outside government to give testimony. You would usually need a Royal Commission, like the one on the abuse of children, to provide such an opportunity. Oh, and our parties, at least publicly, agree that ‘climate change’ is a problem; they just differ about what should be done to ‘fix’ it.
So I look at what Professor Curry is able to do in the USA with envy as well as respect. A little while ago she was asked to take part in a discussion on ‘climate change’ organised by the National Association of Regulatory Utility Commissioners (those who regulate the providers of water, electricity, transportation and the like for local governments), and her counterpart was someone representing the orthodox side. Her testimony is really worth reading in full, and with the powerpoint overheads she used. You can see it all here. I think it is a compelling argument for thoughtful consideration of the costs and benefits of what governments are doing. There is no hysteria, denunciation or over-egging.
She began like this.
In my brief opening remarks, I’m going to focus on areas of uncertainty, disagreement, and confusion in the debate about climate change.
Confusion. Climate science is complicated and can be confusing. But the confusion is exacerbated by politicization of the science and also misleading communication by the media. The recent Sense of the Senate Resolution illustrates the problem.
“Climate change is real and not a hoax” (98-1)
“Climate change is real; and human activity significantly contributes to climate change.” (50-49)
The Senate resolutions highlight the differences and confusion between the scientific versus the political definitions of climate change. The scientific definition states that climate change can be due to natural processes OR persistent human caused changes. The political definition is that climate change is caused by humans. The UN Framework Convention on Climate Change established the political definition in the 1990s.
The political definition effectively defines naturally caused climate change out of existence. However, natural climate change versus human caused climate change is at the heart of the scientific debate. My remarks today will be directed at pointing out the importance of natural climate variability.
So, what do climate scientists agree on? Scientists agree that
*Surface temperatures have increased since 1880
*Humans are adding carbon dioxide to the atmosphere
*Carbon dioxide and other greenhouse gases have a warming effect on the planet.
However there is considerable disagreement about the most consequential issues:
*Whether the warming since 1950 has been dominated by human causes
*How much the planet will warm in the 21st century
*Whether warming is ‘dangerous’
*And whether we can actually do anything to prevent climate change.
Why do scientists disagree? There are a number of reasons:
*Insufficient observational evidence
*Disagreement about the value of different types of evidence
*Disagreement about the appropriate logical framework for linking and assessing the evidence
*Assessments of areas of ambiguity & ignorance.
And finally, the politicization of the science can torque the science in politically desired directions. Uncertainty and disagreement drive scientific progress. However, when a scientific issue becomes politicized, and scientists attempt to speak consensus to power, then a scientific discussion of uncertainties is regarded as an undesirable political act.
If only there were a public arena in Australia where this straightforward and eminently supportable case could be put! There isn’t one, and apart from a Melbourne invited gathering at which I spoke (as did Professor Karoly and others) I can’t immediately recall any such public occasion.
Here’s a bit more of Professor Curry.
The politicization of climate science, and effectively defining natural climate variability out of the public dialogue, has had a very unfortunate impact on the progress of climate science. Have you heard the story about the drunk searching for his lost keys under a streetlight, since that is the only place where he can see anything? Well something similar has been happening with climate science. You find what you shine a light on.
Motivated by the UN Framework Convention and the Intergovernmental Panel on Climate Change and government funding, climate scientists have been focusing primarily on greenhouse gases and to a lesser extent other anthropogenic factors. Other factors important for understanding climate variability have been relatively neglected, I have highlighted long-term ocean oscillations and solar indirect effects, since I think that these are potentially very important on decadal to century timescales…
So what is causing the warming? The recent IPCC AR5 concluded: It is extremely likely that more than half of the observed increase in global average surface temperature from 1951 to 2010 was caused by [humans]. The best estimate of the human induced contribution is similar to the observed warming over this period. The IPCC does NOT have a consistent or convincing explanation for the large warming between 1910 and 1940, the cooling between 1940 and 1975, and the flat temperatures in the 21st century. Until the IPCC is able to explain these variations, I find their high confidence that humans have caused virtually all of the warming since 1950 to be unconvincing.
This is reasoned, sensible stuff, and I commend her whole post to readers. If you disagree, you have to be able to show where she is wrong. No one has been able to do so. What her orthodox critics do is to point to something else, rather than defend their position against her critique.
Given her prominence, and the way the American political system works, it is not surprising that she, along with a few other sceptical scientists, is now the subject of what can fairly been described as a smear campaign. That is perhaps the cost of the more open political system in the USA, and I’ll make that the subject of my next essay.