The Shared Socioeconomic Pathways (SSPs) were developed as a framework for exploring alternative futures with challenges for climate change mitigation and adaptation. Whilst origi-nally developed at the global scale, the SSPs have been increasingly interpreted at the national scale in order to inform national level climate change policy and impact assessments, including mitigation and adaptation actions. Here, we present a set of quantitative SSP scenario projections, based on narratives and semi-quantitative trends, for the UK (the UK-SSPs) for a wide range of sectors that are relevant to the UK climate research, policy and business communities. We show that a mixed-methods approach that combines computational modelling with an interpretation of stakeholder storylines and empirical data is an effective way of generating a comprehensive range of quantitative indicators across sectors and geographic areas in a specific national context. The global SSP assumptions of low challenges to climate adaptation lead to similar socioeconomic outcomes in UK-SSP1 and UK-SSP5, although based on very different dynamics and underlying drivers. Convergence was also identified in indicators related to more efficient natural resource use in the scenarios with low challenges to climate change mitigation (UK-SSP1 and UK-SSP4). Alternatively, societal inequality played a strong role in scenarios with high challenges to adaptation leading to convergence in indicator trends (UK-SSP3 and UK-SSP4).

Regional analyses of risks from climate change require reproducible, consistent and robust approaches to downscaling global socioeconomic scenarios, with coherent processes that work across multiple projects and communities. We address this need by developing an iterative approach to stakeholder-based Shared Socioeconomic Pathway (SSP) downscaling and co-design, enabling us to extend SSPs while maintaining their consistency from global to sub-national scales. We apply this approach to extend a set of SSPs for the United Kingdom, developing a broad range of user-oriented scenario products including (a) a set of key categories of socioeconomic drivers and their dimensions, (b) extended scenario narratives, (c) system diagrams, and (d) semi-quantitative trends of key socioeconomic indicators. Importantly, the co-design process out-lined in this study was implemented fully online, providing valuable lessons on the implications of the online approach for participatory involvement, stakeholder inclusiveness and representativeness. In addition to presenting the approach and its resulting scenario products, we highlight how it contributes to adding detail and nuance, as well as geographic, temporal and sectoral extension to the scenarios. Furthermore, we discuss the benefits of the approach as a reproducible and robust roadmap to SSP downscaling, with respect to deepening the co-design process and increasing scenario legitimacy and validation.

Half of the European Union (EU) land and the livelihood of 10 million farmers is threatened by unsustainable land-use intensification, land abandonment and climate change. Policy instruments, including the EU Common Agricultural Policy (CAP) have so far failed to stop this environmental degradation. BESTMAP will: 1) Develop a behavioural theoretical modelling framework to take into account complexity of farmers’ decision-making; 2) Develop, adapt and customize a suite of opensource, flexible, interoperable and customisable computer models linked to existing data e.g. LPIS/IACS and remote sensing e.g. Sentinel-2; 3) Link economic, individual-farm agent-based, biophysical ecosystem services and biodiversity and geostatistical socio-economic models; 4) Produce a simple-to-use dashboard to compare scenarios of Agri-Environmental Schemes adoption; 5) Improve the effectiveness of future EU rural policies’ design, monitoring and implementation.