The government has agreed a set of carbon values to be used in policy appraisal and evaluation.
The government has updated its set of carbon values to be used in policy appraisal and evaluation. The Treasury’s Green Book provides the government’s overarching policy and project appraisal framework. These carbon values form part of the Green Book supplementary appraisal guidance for valuing greenhouse gas emissions and energy use.
Carbon valuation in policy appraisal
A major review of government’s approach to carbon valuation was conducted in 2009, and provides our current basis for valuing carbon in policy appraisal. The review was updated in 2021 to reflect the latest evidence, targets and wider context.
Update to traded carbon values: 2018
Government’s short-term traded carbon values for use in policy appraisal and modelling were updated in 2018 using the latest market data and assumptions. The overall methodological approach as in 2017 has been used for the 2018 update.
Update to traded carbon values: 2017
Government’s short-term traded carbon values for use in policy appraisal and modelling were updated in 2017 using the latest market data and assumptions. The overall methodological approach as in 2016 has been used for the 2017 update.
Update to traded carbon values: 2016
Government’s short-term traded carbon values for use in policy appraisal and modelling were updated in 2016 using the latest market data. The same methodological approach as in 2015 has been used for the 2016 update:
Update to traded carbon values: 2015
Government’s short-term traded carbon values for use in policy appraisal and modelling were updated in 2015 accounting for the latest market data and revised assumptions that included the EU-wide 2030 energy efficiency, renewables and GHG targets. Overall, the same methodological approach as in 2014 has been used for the 2015 update:
Update to traded carbon values 2014
Government’s short-term traded carbon values for use in policy appraisal and modeling were updated in 2014 in line with latest market data and revised underlying input assumptions. Some of the underlying modelling assumptions were peer reviewed by 2 independent peer reviewers in parallel with this update. Both sets of values and the peer reviewers’ reports are available:
Update to traded carbon values: 2013
In 2013, 2 updates to the traded carbon values were made in 2013. The values used in policy and project appraisal were updated with latest market data. In addition, a further set of traded carbon values were developed, to be used for modelling decision-making in energy markets. Both sets of values are available:
Update to traded carbon values: 2012
The methodological approach underlying the updated traded carbon values used for appraisal was revised in 2012 following the 2011 update. A market-based approach using futures prices was adopted, and is now used for providing the central estimate of traded carbon values. The work on producing updated values for 2012 was peer reviewed by 2 independent peer reviewers whose reports are included with the update.
Update to traded carbon values: 2011
The 2011 edition of the traded carbon values applied the methodology set out in the 2009 ‘Carbon Valuation in UK Policy Appraisal: A Revised Approach’ (see below for further details) but incorporated new data.
Background information on the 2011 update to the traded carbon values is available:
Guidance on estimating carbon values beyond 2050
In June 2010, the government set out an interim carbon value profile over the 2050 to 2100 period to be used for economic appraisal consistent with the agreed carbon values up to 2050.
Shadow price of carbon
This approach and the values it recommends have been superseded following the review in 2008 and early 2009.
In December 2007, the approach to carbon valuation adopted the use of the shadow price of carbon (SPC) as the basis for incorporating carbon emissions in cost-benefit analysis and impact assessments. However, it takes more account of uncertainty, and is based on a stabilisation trajectory.
The SPC is based on estimates of the lifetime damage costs associated with greenhouse gas emissions, known as the social cost of carbon (SCC).
The following document examines the difference between the 2 methodologies and explains the rationale for adopting SPC values.
Peer reviews by leading academic experts commenting on an earlier draft of the paper were submitted. These and the response by DECC economists are available with this document.
Copyright for these peer reviews resides with the authors.
Social cost of carbon
Carbon valuation for policy appraisal no longer uses the social cost of carbon.
The social cost of carbon (SCC) measures the full cost of an incremental unit of carbon (or greenhouse gas equivalent) emitted now, calculating the full cost of the damage it imposes over the whole of its time in the atmosphere. It measures the externality that needs to be incorporated into our decisions on policy and investment options.
The SCC matters because it signals what society should, in theory, be willing to pay now to avoid the future damage caused by incremental carbon emissions.
Because the amount of damage caused by each incremental unit of carbon in the atmosphere depends on the concentration of atmospheric carbon today and in the future, the SCC varies according to the emissions and concentration trajectory the world is on.
The SCC is conceptually different from:
- the market price of carbon, which reflects the value of traded carbon emissions (for example, through the EU Emissions Trading System, EU ETS)
- the marginal abatement cost, which reflects the cost of reducing emissions (rather than the damage if those emissions continue)
In January 2002, a Government Economic Service working paper Estimating the social cost of carbon emissions suggested £19/tCO2 within a range of £10 to £38/tCO2. This cost was set to rise at a rate of £0.27/tCO2 per year to reflect the increasing marginal cost of emissions.
Following the publication of the ‘Stern review on the economics of climate change’, and work commissioned by the Inter-departmental Group on the Social Cost of Carbon, the methodological approach was changed to incorporate use of the shadow price of carbon.
The Inter-departmental group on the social cost of carbon commissioned the research.
Last updated 2 September 2021 + show all updates
Added 2021 review on valuing greenhouse gas emissions in policy appraisal.
Update to traded carbon values: 2018.
2017 traded carbon values published.
2016 traded carbon values published
Update to traded carbon values 2015 published
'Updated short-term values used for modelling purposes 2014' and 'Updated short-term traded carbon values used for UK policy appraisal (2014)' have been added to the collection.