The sixth carbon budget delivery plan was published in October 2025, following court cases brought by groups including Friends of the Earth and ClientEarth1. The plan sets out how the government intends to meet the sixth carbon budget, which covers the five-year period from 2033 to 2037.
The legal challenges concerned the government's earlier failure to publish a plan adequate to meet its legally binding emissions limits. The cases "resulted in the latest delivery plan, published last October", according to Carbon Brief1.
The sixth carbon budget sits within the framework of the Climate Change Act, passed in 2008 by 463 votes to five1. The Act was amended in 2019 by the then-Conservative government to set a long-term goal of cutting emissions to 100% below 1990 levels by 20501. Carbon budgets are binding limits on UK emissions covering successive five-year periods; the UK met its first three, covering 2008 to 2022, and is just over half way through the fourth, covering 2023 to 20271. The sixth and later carbon budgets include the UK's share of emissions from international aviation and shipping1.
In its delivery plan for the sixth carbon budget, the government said roughly a third of UK homes should have heat pumps by 2035 and around half of cars on the road should be electric vehicles1. The Climate Change Committee, which advises the government on carbon budgets, has said electrification and low-carbon electricity supply make up the largest share of emissions reductions in its pathway, with the biggest contributions coming from electrifying transport, heat and industry1.
The government has since set out a draft seventh carbon budget, covering 2038 to 2042, at 535m tonnes of carbon dioxide equivalent, or some 107MtCO2e per year1. This follows the Climate Change Committee's recommendation last year that the UK aim to cut emissions to 87% below 1990 levels under the seventh carbon budget1. In a written statement to parliament, energy secretary Ed Miliband said the target would reduce the UK's exposure to "volatile international fossil-fuel markets and protect bill-payers"1.
"Against the backdrop of heightened geopolitical instability, including the ongoing crisis in the Middle East and its implications for global energy markets, the case for setting a clear and credible long-term pathway for the UK on clean energy and climate action is stronger than ever."
The government's impact assessment for the seventh carbon budget says the UK would need to invest around £880bn over 25 years to meet the budget, but that doing so would yield benefits worth £1,620bn1. It says the budget would help save £445bn up to 2050 from decreasing fossil-fuel imports, and that the UK could cut its reliance on fossil fuels from around three quarters of its energy today to around 15% by 20501.
Why it matters for households
Carbon budgets are legally binding limits on the UK's total emissions, and the delivery plans that accompany them set out the expected pace of change in homes. The sixth carbon budget delivery plan indicates that roughly a third of UK homes should have heat pumps by 20351. For a household, that points to a future in which heating is increasingly electric rather than gas-fired, with the associated changes to how a home is heated and how it draws its energy.
The government's case for the seventh carbon budget rests partly on reducing exposure to fossil-fuel prices. Its impact assessment says the budget would help save £445bn up to 2050 from decreasing fossil-fuel imports, and that the UK could cut its reliance on fossil fuels from around three quarters of its energy today to around 15% by 20501. The assessment is based on fossil-fuel price projections published in 2024, before oil and gas costs surged earlier this year, and says the benefits would be greater, at £1,035bn relative to "no net-zero", if the country faces "persistently high fossil-fuel prices"1.
The government also outlines a less ambitious goal to cut emissions to 83% below 1990 levels by 2040 and a tighter target for 89%1. It says the low end of ambition "increases the risk of underinvestment", while the highest target could face "deliverability risks [that] may undermine [the UK's] credibility"1.
What happens next
There is a deadline of 30 June 2026 to legislate for the seventh carbon budget, subject to parliamentary approval1. The seventh carbon budget must be approved by parliament before the end of June, and the government must then publish a plan to meet it "as soon as reasonably practicable"1. In late May 2026, the Climate Change Committee wrote to Miliband arguing that the 87% by 2040 target "fails to comply with international obligations"1.