Nowhere is the clash between politics and science more stark than in the climate change reports released by the Intergovernmental Panel on Climate Change. The scientific ideal is a neutral, objective piece of communication which clearly lays out what is known and what is not and then hands the issue over to governments and their populaces to work out what to do.

But every description of the challenge of climate change - the way it is framed, the scale of the problem - has political consequences. As the scientific warnings become more stark, the pressure on politicians to tamper with the process only increases. There's no simple solution to this, although it is important to continually stress the difference between the descriptive and the prescriptive. This is difficult where what's at stake is who's to blame for the changes that climate change will cause - a blame game with big political and moral consequences.