The Climate Change Act requires the Government to publish interim five-year carbon budgets which set carbon emissions limits. The carbon budgets set progressively lower emissions limits and act as a roadmap towards achieving the 2020 and 2050 targets. The first three carbon budgets were set in law in May 2009 and cover the periods 2008-12, 2013-17 and 2018-22.
The fourth carbon budget was set in June 2011 and covers 2023-27. For the first four carbon budgets the emissions limits have been set as 3018, 2782, 2544 and 1950 million tonnes of carbon dioxide equivalent (MtCO2e). The Government plans to review the target set for the fourth carbon budget in 2014 in light of the emissions reductions expected from sectors covered by the EU Emissions Trading Scheme.