Researchers at MIT have updated their climatic models and reached conclusions generally in line with the Hadley Centre in the UK, in terms of the amount of warming that would occur by 2100 under a business-as-usual case, in which no significant emissions reductions are achieved:
[T]here is now a nine percent chance (about one in 11 odds) that the global average surface temperature would increase by more than 7Â°C (12.6Â°F) by the end of this century, compared with only a less than one percent chance (one in 100 odds) that warming would be limited to below 3Â°C (5.4Â°F).
It is difficult to express how enormous a change 7Â°C would be. Conservative estimates of the point at which anthropogenic climate change should be considered ‘dangerous’ tend to cluster around the 2Â°C target adopted by the European Union, and others. As the MIT model suggests, a world that does not mitigate emissions may face a 99% probability of experiencing average warming a full degree above that target.
When politicians talking about climate change say that they ‘accept the science,’ people should be asking them if these kinds of projections are part of the science they accept. If so, they ought to be asked why they are treating climate change with such an utter lack of seriousness, concentrating far more on matters of fleeting political concern. In retrospect, it seems that people three or four generations from now will judge our current leaders largely on the basis of their failure to respond effectively to this threat.