Impact assessment for the Sixth Carbon Budget  

The Sixth Carbon Budget defines the UK’s legally binding emissions cap for 2033–2037, mandating a 78% reduction in greenhouse gas emissions compared to 1990 levels. As required by the Climate Change Act, the budget was set following statutory advice from the Climate Change Committee (CCC), which recommended a cap of 965 MtCO₂e. This level was adopted by the UK Government as the preferred option, balancing emissions reduction ambition with technical feasibility, economic implications, and international obligations.

To support this decision, the UK Government carried out a detailed Impact Assessment using the UK TIMES model (UKTM). The assessment tested multiple pathways and policy options, evaluating their impact on emissions, costs, system transitions, and societal outcomes through to 2050. UKTM enabled an integrated analysis of the full UK energy and land-use systems, identifying least-cost trajectories consistent with the CCC recommendation. The modelling was central to assessing whether the target was achievable and to understanding trade-offs between early action, long-term flexibility, and economic impact.

This work fed into a broader analytical programme that included consultations, scenario development, and stakeholder engagement. The resulting evidence base helped to confirm that the recommended Sixth Carbon Budget target was deliverable and aligned with the UK’s goal of reaching net zero by 2050.