Assumptions
Global Warming Potentials
The CAT uses Global Warming Potential (GWP) values from the IPCC’s Fourth Assessment Report (AR4) for all figures and time series.
Historical emissions
Historical emissions data were obtained from the ‘Final UK greenhouse gas emissions national statistics: 1990-2017’ (UK Government, 2019l). Provisional emission data for 2018 was also included (UK Government, 2019m). The UK provides inventory data to the UNFCCC that includes emissions from Overseas Territories and Crown Dependencies, which are not covered by UK climate policy and are not included in government emission projections. For this reason, we have chosen to use national emission statistics rather than UNFCCC inventory emissions.
Pledges and targets
For the 2020 target, we took the average emission level across the five years of the UK’s third carbon budget and subtracted the projected level of removals from LULUCF in that year (UK Government, 2019a). LULUCF is projected to provide an accounting contribution of -16 MtCO2e in 2020. For comparability between countries, the CAT presents all targets excluding LULUCF.
For the 2030 target, we took the average emission level across the five years of the UK’s fifth carbon budget and subtracted the projected level of removals from LULUCF in that year (UK Government, 2019a). LULUCF is projected to provide an accounting contribution of -11 MtCO2e in 2030.
For the 2050 net-zero target, we took the upper and lower projections of the CCC’s LULUCF emissions in 2050 (Core Scenario and Further Ambition minus Energy crops, agroforestry & hedges) and added this to the zero emission baseline (Committee on Climate Change, 2019e).
Current policy projections
The current policy projections from 2018 to 2030 were obtained from greenhouse gas emission projections updated annually by the UK Government which were then harmonised to the latest historical and provisional (2018) data (UK Government, 2019a). The UK’s annual emission projection report presents projections considering future impacts of policy measures enacted as of July 2018 (For details of the policies included, see Annex D of the BEIS Updated Energy and Emissions Projections 2018 report) (UK Government, 2019k). The CAT assesses the policies contained in the ‘Existing Policies’ scenario.
Planned policy projections
The planned policies projection shown in the CAT is taken from the UK government’s ‘Reference Scenario’ which includes all the policies contained within the aforementioned ‘Existing Policies’ scenario, as well as policies where “decisions on policy design are sufficiently advanced to allow robust estimates of impact (i.e. including "planned" policies).” It is then harmonised with historical and provisional emissions as above (For details of the policies included, see Annex D of the BEIS Updated Energy and Emissions Projections 2018 report).
Further analysis
Latest publications
Stay informed
Subscribe to our newsletter