The past few days have seen a big increase in media coverage of climate science as the world awaits the release of the IPCC’s AR5 WGI report at the end of this week.
Media stories have focused on a wide range of issues, with some looking at Arctic sea ice and others claiming that climate models exaggerate the rate of future warming.
In fact it has just been announced that this year Arctic sea ice reached its sixth lowest minimum extent since satellite records began in 1979 and all those years have occurred in the last decade. The long-term decline of Arctic sea ice is one of the most visible of many different signs that our world is warming – a point which few people dispute.
It is also well-established that if we increase concentrations of greenhouse gasses in the atmosphere, then global temperatures will rise. The debate is about how much the world will warm, where it will warm fastest and what the implications are for us.
It claims the Met Office climate model used to make those projections, HadCM3, contains an error and that, because of this error, the projections overestimate warming. The GWPF’s article, however, accepts that the claims of an error have not been substantiated.
UKCP09 used a sophisticated method that used both model projections and observations to provide a range of potential future warming which attempts to take in the uncertainties in model parameters. The GWPF article fails to note that UKCP09 also used information from many other climate models, and that the projections were independently reviewed prior to publication.
Ultimately there is nothing in the GWPF article which undermines UKCP09 or the way climate models, including the Met Office’s HadCM3, project future temperature changes.