To ask Her Majesty's Government how much of the estimated £324 billion to £404 billion cost of implementing the Climate Change Act 2008, as set out in the March 2009 impact assessment by the Department of Energy and Climate Change, will be borne by the public sector; and how much by the private sector.

The Climate Change Act sets out a long-term target for UK net greenhouse gas reductions and a framework of five-yearly carbon budgets, the level of which will be set using advice from the Committee on Climate Change. The costs presented in the Climate Change Act impact assessment (IA) are based on the estimated reduction in UK gross domestic product (GDP) from the constraints the Act creates on UK net greenhouse gas emissions.

The costs are estimated for an indicative trajectory to reach the long-term target of an 80 per cent reduction in UK net emissions (compared to 1990 levels) by 2050. The estimate of the costs comes from modelling work performed by the Committee on Climate Change, which has stated:

"A combination of existing technologies, and those currently under development, could deliver the required global emissions reduction at an economic cost of 1-3 per cent of GDP in 2050 in line with the conclusions of the Stern Review. The UK could achieve an emissions reduction of 80 per cent below 1990 levels at a cost of 1-2 per cent of GDP in 2050."

The Climate Change Act does not propose specific policies or their method of implementation. The £324 billion to £404 billion cost is an estimate of the underlying technology and behaviour change costs required to deliver the reductions over the period between 2008 and 2050. The incidence of this cost will depend on the specific design of the policies that are implemented—the share of the cost borne by the public or private sector is contingent on policy decisions between now and 2050.

Any new policies put forward to meet each of the five-yearly carbon budgets will be subject to an individual impact assessment which will look in detail at the costs and benefits of the specific policy and will identify the distributional impacts on the private and public sectors.