UKESM contribution to policy

Scientific papers based on UKESM1 simulations form an important contribution to the Intergovernmental Panel on Climate Change (IPCC) – 6th Assessment Report (AR6). The IPCC provides policymakers with regular scientific assessments on climate change, its implications and potential future risks, as well putting forward adaptation and mitigation options.

An emphasis of UKESM is on interactions and future feedbacks involving the physical climate system, the carbon cycle, atmospheric composition and aerosols:

• Using the CO₂ emission-driven version of UKESM1 (em-UKESM1) we can provide estimates of available carbon emissions to keep global warming below key targets e.g. 1.5 or 2°C.
• We will use em-UKESM1 to sample a range of “overshoot” future scenarios, where global warming exceeds a given target before returning to it at a later date.
• We will assess the risk of abrupt changes in the Earth system and the potential reversibility of such changes in these overshoot scenarios. This information is urgently required by policymakers.

UKESM1 enables analysis of potential future changes in both the physical climate system (such as rainfall, temperature and storms) while also allowing analysis of changes in the Earth’s biogeochemical systems, such as marine biology, forests and atmospheric gases, all within a single interacting model.

UKESM1 historical and future projections have been analysed to understand the impacts on, for example, storm surges and coastal flooding, fisheries, agriculture and wind potential over discrete regions, such as the Arctic, the North Atlantic-Europe (with ACSIS) and the Southern Ocean/Antarctica (with ORCHESTRA), as well with respect to key regional phenomena, such as global monsoons and the El Nino–Southern Oscillation.

Through European projects (CRESCENDO, ESM2025 and OptimESM), UKESM works with European Earth System Model (ESM) teams and Integrated Assessment Models (IAMs) to improve the representation of key processes in the Earth system models and develop more reliable simulations of future climate change.

Policy briefings and events, where we talk to policymakers directly, are a key part of how we communicate the results of the research from Earth system modelling.