The impact of uncertainties on the UK's medium-term climate change targets

This paper carries out an assessment of the feasibility of the UK's agreed low carbon pathway over the medium term, with a particular focus on the fourth carbon budget (2023-27). It analyses the uncertainties associated with the specific changes that may be necessary to comply with this carbon budget - including measures to decarbonise electricity, heat and transport. This analysis focuses on 'instrumental' uncertainties associated with specific areas of the energy system (e.g. the decarbonisation of heat in households) and 'systemic' uncertainties that tend to have more pervasive implications for the energy system as a whole (e.g. uncertainties associated with public attitudes). A framework is developed that sets out and analyses the key uncertainties under those two broad categories, in terms of their complexity and their potential impact on the fourth carbon budget. Through the application of this framework the paper also considers strategies to mitigate or manage these uncertainties, and which actors could help develop and implement these strategies.