In the run up to the 2009 budget, Green Alliance has asked five leading commentators to explain how they see the risks of climate change and to set out why these are risks we cannot afford to take.

Britain finds itself at an historic moment; the threat of climate change is clear, the Committee on Climate Change has outlined the path we must take in reducing emissions from all sectors of the economy and Government action on an unprecedented scale is both necessary and urgent. This action will come at a price and, in times of economic uncertainty, there is a risk it will appear too expensive and difficult.

The private sector will need to do much, but government expenditure to kick start major programmes in energy efficiency, research and development and low carbon infrastructure will be absolutely essential if the targets in the Climate Change Act are to be met. Part I of this series, produced by Martin Rees, explores the risks of ignoring the science, whilst Part II, by Paul Ekins, sets out what the Government must do in respect of public investment and why.