- Bishop Hill blog

There are a lot of people venting about David Rose's article in the Mail on Sunday and I keep pressing them to be clear about whether Rose has got anything of substance wrong. As far as I can see, the only person who has made any kind of a case is James Annan.

Today it's Myles Allen's turn. Writing in the pages of the Guardian he says this:

...I find David [Rose] quoting me in the Mail on Sunday as saying that "until recently he believed that the world might be on course for a catastrophic temperature rise of more than five degrees this century" and "adding that warming is likely to be significantly lower".

I have argued for years that the odds on a high climate sensitivity are largely irrelevant to the warming we should expect over the coming century, and I certainly never suggested to David that my assessment of the odds on any particular level of warming by 2100 had changed. Sure, current rates of warming in the highest-response models are looking iffy, for reasons that may or may not be relevant to their forecasts for 2100, but at the rate emissions are rising, you don't need a particularly high climate response to get to four degrees by 2100 and five degrees not long thereafter. The only time I mentioned five degrees in our conversation was in the context of the long-term response to doubling CO2.

Myles has previously issued a press release telling us that warming could be as high as 11°C (see p4 here) a position he has repeated on other occasions (see transcript here):

What we found – here are the two just sort of accepted consensus range of uncertainty in the warming expected if, for example, one were to double pre-industrial carbon dioxide levels–that’s a level of carbon dioxide which is expected within the next few decades– would be between 1.5 and 4.5 degrees Centigrade...Anyway, that is the consensus up until now. What we found is these models being fed back to us from our participants show– by just varying the things within the ranges of uncertainty, varying certain aspects of the model within the range of uncertainty– these models are giving us warmings to that same increasing carbon dioxide, ranging to up to over 10 degrees Centigrade.

I'm therefore not sure he is protesting much. Like so many others, this looks as though it's being seen to be rude to the sceptic rather than actually making a case of any substance.