Climate Change Act 2008 · seven Orders
UK carbon budgets: seven ceilings, one duty-holder
A carbon budget is a five-year cap on the net UK carbon account, set by Order under the Climate Change Act 2008.
Seven have been set, from 3,018 MtCO2e for 2008–2012 to 535 MtCO2e for 2038–2042.
They bind the Secretary of State, not companies.
Definition
What is a carbon budget?
Section 4(1) of the Climate Change Act 2008 makes it the Secretary of State’s duty to set, for each five-year period from 2008–2012 onwards, an amount for the net UK carbon account: the carbon budget.
The same subsection makes it the Secretary of State’s duty to ensure the net UK carbon account for each period does not exceed that budget.
Each budget is set by its own Order, and each Order states the budget in tonnes of carbon dioxide equivalent.
The seven budgets
All seven, Order by Order
The first three budgets were set together in 2009; each later one was set by its own Order.
| Budget | Period | Level (MtCO2e) | Order (article 2) | Made |
|---|---|---|---|---|
| CB1 | 2008–2012 | 3,018 | SI 2009/1259 | 20 May 2009 |
| CB2 | 2013–2017 | 2,782 | SI 2009/1259 | 20 May 2009 |
| CB3 | 2018–2022 | 2,544 | SI 2009/1259 | 20 May 2009 |
| CB4 | 2023–2027 | 1,950 | SI 2011/1603 | 29 June 2011 |
| CB5 | 2028–2032 | 1,725 | SI 2016/785 | 20 July 2016 |
| CB6 | 2033–2037 | 965 | SI 2021/750 | 23 June 2021 |
| CB7 | 2038–2042 | 535 | SI 2026/695 | 25 June 2026 |
The seventh budget, set by the Carbon Budget Order 2026, was made on 25 June 2026 and came into force the next day.
The Climate Change Committee published its response to Parliament passing it on 24 June 2026.
UK carbon budgets, MtCO2e
- CB1, 2008–20123,018
- CB2, 2013–20172,782
- CB3, 2018–20222,544
- CB4, 2023–20271,950
- CB5, 2028–20321,725
- CB6, 2033–2037965
- CB7, 2038–2042535
Each figure is article 2 of its Order; the Orders state tonnage only.
Who is bound
They bind government, not companies
A carbon budget is a national ceiling that the Secretary of State must set and stay under.
It creates no obligation on any company, so “complying with carbon budgets” is not something a business can do.
The 2050 target in section 1(1) has the same shape: it is the Secretary of State’s duty to ensure the 2050 account is at least 100% below the 1990 baseline.
That target was 80% until SI 2019/1056 changed it on 27 June 2019.
Percentages
Why this page gives tonnes, not percentages
The Orders state tonnage only; percentage equivalents come from government commentary, and every one needs its baseline year, 1990.
The government’s own figures for the sixth budget differ: 78% in its 2021 announcement, about 76% computed on its guidance page from the 965 MtCO2e cap.
The UK’s 2035 Nationally Determined Contribution, submitted on 30 January 2025, commits to at least 81% below 1990 by 2035; it is a Paris Agreement commitment, and the sixth budget has not been amended to match it.
Scope
UK-wide, not devolved
These budgets are set under the UK Act.
Scotland and Wales have their own climate legislation, the Climate Change (Scotland) Act 2009 and the Environment (Wales) Act 2016, which this page does not cover.
The Act behind the budgets, and its adaptation duties, are on the Climate Change Act 2008 page.
Frequently asked
UK carbon budgets, answered
What is a carbon budget?
Under section 4(1) of the Climate Change Act 2008, a carbon budget is the amount the Secretary of State sets for the net UK carbon account for a five-year period.
The Secretary of State must then ensure the account for that period does not exceed it.
How many UK carbon budgets are there?
Seven have been set by Order, covering 2008 to 2042.
The seventh, set by the Carbon Budget Order 2026 (SI 2026/695), is 535 MtCO2e for 2038–2042.
Do carbon budgets apply to companies?
No. Section 4(1) makes them the Secretary of State’s duty.
A carbon budget creates no obligation on any company, so a company cannot “comply with” one.
What is the seventh carbon budget?
The Carbon Budget Order 2026, made on 25 June 2026 and in force on 26 June 2026, sets the budget for 2038–2042 at 535,000,000 tonnes of carbon dioxide equivalent.
Is the carbon budget the same as the UK’s 2035 target?
No. The sixth carbon budget (2033–2037) is set under the Climate Change Act.
The UK’s 2035 Nationally Determined Contribution, submitted on 30 January 2025, commits to at least 81% below 1990 levels by 2035 under the Paris Agreement.
The sixth budget has not been amended to match it.
What percentage reduction is each carbon budget?
The Orders state tonnes only, never a percentage.
Government commentary gives percentages against the 1990 baseline, and for the sixth budget its own figures differ: 78% in the 2021 announcement, about 76% computed on its guidance page.
Sources
Primary sources
Every figure on this page is article 2 of its Order or a section of the Act.
- legislation.gov.ukClimate Change Act 2008, section 4
The Secretary of State’s duty to set each carbon budget and stay within it.
- legislation.gov.ukClimate Change Act 2008, section 1
The 2050 target: at least 100% below the 1990 baseline.
- legislation.gov.ukSI 2009/1259, article 2
The first three budgets.
- legislation.gov.ukSI 2011/1603, article 2
The fourth budget, 2023–2027.
- legislation.gov.ukSI 2016/785, article 2
The fifth budget, 2028–2032.
- legislation.gov.ukSI 2021/750, article 2
The sixth budget, 2033–2037.
- legislation.gov.ukThe Carbon Budget Order 2026 (SI 2026/695), article 2
The seventh budget, 535,000,000 tonnes for 2038–2042; made 25 June 2026, in force 26 June 2026.
- legislation.gov.ukSI 2019/1056, article 2
Changed 80% to 100% on 27 June 2019.
- GOV.UK (DESNZ)UK’s 2035 Nationally Determined Contribution
The international commitment, a separate instrument from the carbon budgets.
- GOV.UKCarbon budgets (guidance)
Government commentary; its percentage equivalents appear in no Order.
- Climate Change CommitteeCarbon budgets, targets and progress
The statutory adviser’s hub, including its response to Parliament passing the seventh budget (24 June 2026).