An article appears in the Mail on Sunday today focusing on the Intergovernmental Panel on Climate Change’s (IPCC) forthcoming Fifth Assessment Report (AR5) which it bills this as the ‘world’s most authoritative climate study’.
It’s fair to say that AR5 is expected to be the most comprehensive review of climate change science to date. The first part of the report, from its Working Group I (WGI), has been worked on by more than 800 scientists from around the world who have assessed more than 9,000 scientific publications and taken into account more than 50,000 comments from over 1000 expert reviewers.
The WGI report is now in its final stages and the major conclusions will be finalised and released on 27 September. It is at that point that we should debate its findings and their implications.
Further parts of the report, from its Working Group II and III, as well as a final version of the whole report will be published next year.
The Mail article also discusses the recent pause in warming, which the Met Office looked at in a series of papers, released in July. Many of the issues raised in the article are addressed in those reports, which you can see on our website.
The article also goes on to mention some of the claims made in a commentary published by Nic Lewis yesterday. This is a lengthy and technical commentary covering several topics and will require time to provide as helpful a response as possible, so further comment will be released in due course.
There are a couple of points raised in the Mail story which should be addressed now, however.
The article states that the Met Office’s ‘flagship’ model (referring to our Earth System Model known as HadGEM2-ES) is too sensitive to greenhouse gases and therefore overestimates the possible temperature changes we may see by 2100.
There is no scientific evidence to support this claim. It is indeed the case that HadGEM2-ES is among the most sensitive models used by the IPCC (something the Met Office itself has discussed in a science paper published early this year), but it lies within the accepted range of climate sensitivity highlighted by the IPCC.
Equally when HadGEM2-ES is evaluated against many aspects of the observed climate, including those that are critical for determining the climate sensitivity, it has proved to be amongst the most skilful models in the world.
Finally, in our aim to provide the best possible scientific advice to the UK Government, the Met Office draws on all the scientific evidence available to us. This includes many other physically based climate models from leading research centres around the world, which provide a range of climate sensitivities and a range of potential future warming.