The best summary of the ‘climate change’ issue I have read for a long time

This is my last post for the year, and given that ‘climate change’ has been the dominant theme in 2015, and that the Paris Agreement has been accepted, at least in Paris, I thought I would finish the year with a simple piece on the ‘climate change’ issue. Most of it is the text of the verbal remarks that Professor Judith Curry made to a Senate Committee she was delivering her testimony to in early December. There’s nothing new in it, but she said it accessibly and well. For those who don’t know who she is, Professor Curry is probably the most distinguished climate scientist in the USA who  disputes the alarmism of the Obama administration and the scientists who support it.

There are others like her, like Professor Will Happer from Princeton, and Professor Richard Lindzen from MIT, not to mention Professors Spencer and Christy who manage the UAH satellite temperature database. But Ms Curry runs a very good website as well. It is my ‘go-to’ site for finding out, and for reading debate between the various sides of the climate science issue. On her website comments and essays are nearly always temperate and well-researched, though there are couple of regular commentators whose purpose seems to be to derail whatever the subject of the post is.

This is what she said.

Prior to 2009, I felt that supporting the IPCC consensus on climate change was the responsible thing to do. I bought into the argument: “Don’t trust what one scientist says, trust what an international team of a thousand scientists has said, after years of careful deliberation.” That all changed for me in November 2009, following the leaked Climategate emails, that illustrated the sausage making and even bullying that went into building the consensus.

I starting speaking out, saying that scientists needed to do better at making the data and supporting information publicly available, being more transparent about how they reached conclusions, doing a better job of assessing uncertainties, and actively engaging with scientists having minority perspectives. The response of my colleagues to this is summed up by the title of a 2010 article in the Scientific American: Climate Heretic Judith Curry Turns on Her Colleagues.

I came to the growing realization that I had fallen into the trap of groupthink. I had accepted the consensus based on 2nd order evidence: the assertion that a consensus existed. I began making an independent assessment of topics in climate science that had the most relevance to policy.

What have I concluded from this assessment?

Human-caused climate change is a theory in which the basic mechanism is well understood, but whose magnitude is highly uncertain. No one questions that surface temperatures have increased overall since 1880, or that humans are adding carbon dioxide to the atmosphere, or that carbon dioxide and other greenhouse gases have a warming effect on the planet. However there is considerable uncertainty and disagreement about the most consequential issues: whether the warming has been dominated by human causes versus natural variability, how much the planet will warm in the 21st century, and whether warming is ‘dangerous’.

The central issue in the scientific debate on climate change is the extent to which the recent (and future) warming is caused by humans versus natural climate variability. Research effort and funding has focused on understanding human causes of climate change. However we have been misled in our quest to understand climate change, by not paying sufficient attention to natural causes of climate change, in particular from the sun and from the long-term oscillations in ocean circulations.

Why do scientists disagree about climate change? The historical data is sparse and inadequate. There is disagreement about the value of different classes of evidence, notably the value of global climate models. There is disagreement about the appropriate logical framework for linking and assessing the evidence. And scientists disagree over assessments of areas of ambiguity and ignorance.

How then, and why, have climate scientists come to a consensus about a very complex scientific problem that the scientists themselves acknowledge has substantial and fundamental uncertainties?

Climate scientists have become entangled in an acrimonious political debate that has polarized the scientific community. As a result of my analyses that challenge IPCC conclusions, I have been called a denier by other climate scientists, and most recently by Senator Sheldon Whitehouse. My motives have been questioned by Representative Grijalva, in a recent letter sent to the President of Georgia Tech.

There is enormous pressure for climate scientists to conform to the so-called consensus. This pressure comes not only from politicians, but from federal funding agencies, universities and professional societies, and scientists themselves who are green activists. Reinforcing this consensus are strong monetary, reputational, and authority interests.

In this politicized environment, advocating for CO2 emissions reductions is becoming the default, expected position for climate scientists. This advocacy extends to the professional societies that publish journals and organize conferences. Policy advocacy, combined with understating the uncertainties, risks destroying science’s reputation for honesty and objectivity – without which scientists become regarded as merely another lobbyist group.

I would like to thank the committee for raising the issue of data versus dogma in support of improving the integrity of climate science.

This concludes my testimony.

There is a good video of her responding to Senator Markey during the hearing, here.

Why don’t we in Australia have people of her calibre holding senior positions in universities and speaking out about the flaws in the official doctrine promulgated by the IPCC? The flaws and uncertainties are not so hard to find, after all, as Judith Curry points out. One reason is that, in contrast to the US, there is general, if tepid, acceptance within our major political parties that ‘global warming’ is important and probably a worry. In the USA the Republicans and Democrats differ sharply on this question.

The second is that within the bureaucracy, with a few exceptions (like sea-level in NSW), there is also agreement that something has to be done. To speak out against that apparent certainty is, for people seeking employment, to risk appointment, promotion and funding. It is one pernicious aspect of current political correctness; there are others. Yes, we have excellent people who speak out, like Professor Bob Carter, Dr Jennifer Marohasy, Joanne Nova, Garth Paltridge, Alan Moran, and several others. But all of them, like me, have had to put up with official disapproval and hostility. In the Federal Parliament there has been only one politician, Dr Dennis Jensen, who has voiced the critical side.

In the new year I’ll resume posting on 11 January, all being well. In the meantime a Merry Christmas and a Happy New Year to you all. And just for fun, Geoff Derrick’s sardonic comment on CoP21.

The Idiocene


Join the discussion 20 Comments

  • David says:

    Merry Christmas Don. I am looking forward to reading your posts next year.

  • dlb says:

    Thanks Don for being a voice that needs to be heard.
    You must be starting to hit the mark as a few critics are now showing up.

  • Dasher says:

    Senator Markey looked very lightweight when Curry spoke to him. Literally nothing to say apart from a silly boiler plate comment about the hottest year (hottest by how much Senator?) and yet this man wields considerable power. I agree we need a sensible debate but I won’t hold my breath. It underscores the importance of people like you Don ( and of course Curry, Linden et al.)..not because you necessarily have the answer but because you do shine a light on some of the utter tripe that passes for settled science or informed opinion. Don’t weaken, keep up the good work in 2016 and all the best to you and you family for the festive season.

  • steve jackson says:

    I’ve read everything you have written on this subject Don..thanks for your articulate intelligence and relaxed style. Always refreshing to read what you have to say, and reading you always puts me in a better mood about this issue! I’m sure you are aware you have many readers like me who appreciate what you do, so please continue to do what you do so well. Cheers, Steve.

  • bobo says:

    I’m not particularly familiar with Judith Curry’s perspective, how is her view at odds with the latest IPCC physical sciences basis synthesis report? From my fleeting acquaintance with her work it seems that she never actually contradicts it.

    I do have to say that it is curious that she essentially presented a nice narrative, a story, as her testimony. It’s an odd thing for a scientist to do, to say the least. It appears more hand-wavy vaudeville than anything serious, playing to her fan-base.

    • Read some of the hundred of detailed posts on her blog: I must have missed the “hand-wavy vaudeville” in amongst the lucid common sense of a hard working courageous scientist.

    • David says:

      Hi Bobo

      As I see it Curry is still in the tent and so broadly accepts the science, (unlike David Evans) but balks at the implications.

      Her main argument is that insufficient resources are devoted to identifying other possible causes of global warming. Her favorite candidates are natural internal variability and solar variability” plus the unknown unknowns.

      Curry’s is “waiting for Godot”

      • David says:

        What you will find mainly find these wait_&_see arguments in the grey literature, submissions to Congress etc. However, I could find no empirical examination of solar variability in her published articles.

        I would have thought

        (1) Curry should practice what she preaches and spend a bit more time looking at this issue.

        (2) Curry has looked at the issues, but does not “agree” with her findings. .

        • donaitkin says:


          You are a tough judge. Solar variability is the research province of solar physicists, and JC’s published work is mostly in the areas of hurricanes, remote sensing, climate modelling and related areas of climate science. But I’m surprised that you could find no evidence of at least her interest in the area of ‘solar variability’ and her capacity to bring forward published research that might be of interest to her readers. Just searching for ‘solar variability’ on her website produced 50 posts in which it was mentioned.

          Perhaps you could devote some proper time over the next few weeks to reading widely in her website. She does draw responses from the orthodox as well as sceptics, and the debates there are always worth reading. You might even come to see that much of the science is not at all settled.

          • David says:

            I don’t mean to be tough. Its just that I have noticed that while the idea does appear frequently on her web page it does not appear in her empirical research, as far as I could see.

            But as you say there may be good reasons for this.

            But my guess is that she has spent a few rainy afternoons adding sun spot data and the like to her models but it has made no difference.

    • dasher says:

      I have read many articles against Curry’s work, many by her peers. Much of it is personal abuse which always makes me wonder the strength of their arguments. It is also typical of the conversation on climate change. Those who deviate from the orthodoxy are heretics which is a worry. It is also why I won’t hold my breath waiting for a sensible debate. I get back to Senator Markey dreadful performance against Curry ..and he apparently is the hero in this story! By the way I thought her testimony was OK for what is was mean’t to do..she could have explained ( which she acknowledged) to Markey why the “hottest year on record” was not such a big deal ( slight increase above flatline) but of course if it was not for Steyn she would not even had a chance to respond against his abuse.

  • Doug~Cotton says:

    If you are interested in what is the correct physics which explains all observed data anywhere, and is also confirmed by experiments with centrifugal force, you’ll find it in my website and my blog and linked papers, videos and a book.

  • JMO says:

    Wishing you and your family have a rea Christmas. I have enjoyed reading your postings.

  • Alan says:

    The house of cards is collapsing –…/homogenized-us-warming-trend-may-be-grossly-exagg..

  • […] I was astonished at the abuse I received — though there were a few supportive commenters as well. I went back over what I had written. Where was I grossly wrong? I couldn’t find gross errors. Now hooked on the topic, I began to read even more widely, met some of the prominent sceptics in London, began to explore the blogosphere, and corresponded with some people whose papers I had read. In 2010 Judith Curry, Professor of Earth and Atmospheric Sciences at Georgia Tech., started a website called ‘Climate etc’, which I read every time it was published.  In time I offered her essays that she might like to publish, and four of them appeared in her blog (link below). Two years later I thought I should set up my own website, and that has meant that I have written very little for anyone else. This website consumes a great deal of my time and energy, as I said in the last post for 2015. […]

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