I saw your piece "Do you believe in climate change?" in The Guardian. Your piece states that "this is a matter of science and therefore of evidence – and there's lots of it", that a "whole range of different datasets and independent analyses show the world is warming", and that there is "overwhelming evidence for man-made climate change".
Your piece, though, does not specify the analyses or detail the evidence. I ask you to detail a single piece of observational evidence, and supporting analysis, for global warming. There should be enough detail to allow me to reproduce the analysis.
Your piece includes a link to a MetOffice web page named "evidence":
The web page claims this: "the average temperature over the first decade of the 21st century was significantly warmer than any preceding decade in the instrumental record, stretching back 160 years" (emphasis added). If you would present analysis that demonstrates this claim is valid, that would be ample.
Sorry for the delay in getting back to you. I have been away for a while and have been talking to some of my colleagues here, who are more expert in statistics. I believe that you have corresponded with some of them before. Doug McNeall in talking about the significance of global warming makes the point:
"However, I personally would not state the “significance” of linear trends in chapter 3, as occurs in table 3.2, for example. I think that this uncertainty communication could easily get confused with a formal attribution statement. Unfortunately, I don’t have a ready, simple alternative to suggest at the moment. I think that any suggestions that you (or others in the statistical community) might have on this topic would be well received by the climate science community.
As a scientist with Bayesian leanings, I think that discussions of “significance” of trends are often misguided, and distracting. They are too easily conflated with the informal notion of significance, as aptly demonstrated in the recent discussions of the significance (or otherwise) of recent trends of surface warming on the BBC news website. They tend to focus too closely on arbitrary levels of significance, with little justification, and are often misinterpreted. There are many fundamental problems with the philosophy of significance testing, particularly when applied to climate science (see e.g. Ambaum 2010)."
My article was really about the way that people in general misunderstand how science works, rather than trying to present the evidence. Rather than look objectively at the evidence they often expect a right or wrong answer. Their interpretation is based on their belief system and how they view scientists and science generally. As scientists in this field we need to improve the way that we communicate science to help those that do not want to go into the detail themselves. We also need make as much information available as possible about what has gone into our decision making, for those that are interested in the detail.
Your article in The Guardian was written, apparently, because public opinion on global warming is moving away from what you think it should be. Studies of public opinion formation (for any issue) seem to conclude that the biggest drivers are word of mouth and peer pressure. Hence, to understand the reason for the movement in public opinion on global warming, consider what has been motivating word of mouth and peer pressure.
Nowadays, much of that motivation is germinated on blogs. It is on blogs that people who strongly care about a subject tend to congregate. Those people will support and motivate each other, and then talk with their friends and families and colleagues and so on. Public opinion is thereby moved. (There are other factors, of course.)
So how did blogs react to your article? Here are some typical comments from the UK's leading climate blog, Bishop Hill:
Another blog, Climate Resistance, also had a long critical post about your article, with comments such as "That’s an amazing pack of lies from Vicky Pope".
So your article might have helped to strengthen skepticism about global warming.
Please note that in saying the above, I am little more than a messenger. I have no control over comments on blogs.
Would any article in support of global warming bring out such reactions from skeptics? No. Your colleague Richard Betts strongly upholds global warming. Yet Richard is highly regarded by UK skeptics. Another example is Tamsin Edwards at Bristol. Richard and Tamsin are respected, even admired.
I note that your message does not present any piece of observational evidence, despite my asking for one piece. Indeed, there is no observational evidence. The claim about such evidence in your article is untrue.
There is, however, evidence for global warming: from computer models of the global climate system. You were the manager of climate model development, for what is considered by many researchers to be the world's best climate model, at Hadley. Hence I am wondering why your article did not rely on that evidence--?
Assessing observational evidence requires specialized statistical skills (typically time series). You appear to not have those skills. In other words, you wrote an article about a subject that you are not trained in, while implicitly claiming to be an authority on that subject. And you could have written an article about a subject on which you actually are an authority.
You are right about the blogs, although how strongly and quickly this spreads into the general population I am not sure.
I am pleased that you value Richard and Tamsin's contributions so highly, I do too.
Thanks for your summary of the key issues. I will think about how and where to respond to the particular points that you raise.
You are right of course that my expertise is in climate modelling and not in statistics. However, I do have access to colleagues with expertise in a wide range of disciplines and I consult them for advice.