Applying the global RCP–SSP–SPA scenario framework at sub-national scale: A multi-scale and participatory scenario approach

Abstract

To better anticipate potential impacts of climate change, diverse information about the future is required, including climate, society and economy, and adaptation and mitigation. To address this need, a global RCP (Representative Concentration Pathways), SSP (Shared Socio-economic Pathways), and SPA (Shared climate Policy Assumptions) (RCP-SSP-SPA) scenario framework has been developed by the Intergovernmental Panel on Climate Change Fifth Assessment Report (IPCC-AR5). Application of this full global framework at sub-national scales introduces two key challenges: added complexity in capturing the multiple dimensions of change, and issues of scale. Perhaps for this reason, there are few such applications of this new framework. Here, we present an integrated multi-scale hybrid scenario approach that combines both expert-based and participatory methods. The framework has been developed and applied within the DECCMA project with the purpose of exploring migration and adaptation in three deltas across West Africa and South Asia: (i) the Volta delta (Ghana), (ii) the Mahanadi delta (India), and (iii) the Ganges-Brahmaputra-Meghna (GBM) delta (Bangladesh/India). Using a climate scenario that encompasses a wide range of impacts (RCP8.5) combined with three SSP-based socio-economic scenarios (SSP2, SSP3, SSP5), we generate highly divergent and challenging scenario contexts across multiple scales against which robustness of the human and natural systems within the deltas are tested. In addition, we consider four distinct adaptation policy trajectories: Minimum intervention, Economic capacity expansion, System efficiency enhancement, and System restructuring, which describe alternative future bundles of adaptation actions/measures under different socio-economic trajectories. The paper highlights the importance of multi-scale (combined top-down and bottom-up) and participatory (joint expert-stakeholder) scenario methods for addressing uncertainty in adaptation decision-making. The framework facilitates improved integrated assessments of the potential impacts and plausible adaptation policy choices (including migration) under uncertain future changing conditions. The concept, methods, and processes presented are transferable to other sub-national socio-ecological settings with multi-scale challenges.

Projected changes in rainfall and temperature over the Philippines from multiple dynamical downscaling models

“…The choice of these time periods allowed all 12 simulations to be considered (the future time period by the~12 km resolution HadGEM3-RA experiments was restricted to 2036-2065). All simulations use the RCP8.5 scenario meaning that, whilst they do not sample the uncertainty due to greenhouse gas forcing, the projections are appropriate for stress testing and adaptation planning where there is a need to generate "worst case" scenarios (e.g., Kebede et al, 2018). The projections of climate change using the RCP8.5 scenario for the chosen time periods aim to provide helpful and timely information for formulating local climate change adaptation and mitigation plans in the Philippines.…”

Building Regional Sustainable Development Scenarios with the SSP Framework

“…(2) The variables and data of regional impact assessment models need bias correction to make them more suitable to the local situation which needs to collect lots of historical data and other relative climate data, but some data are missing [18]. (3) Formulating regional climate policies needs to consider global temperature goals and stakeholders [18,[25][26][27][28]. If policies are in conflict with stakeholders, it is difficult to be carried out.…”

“…To meet the global temperature goal within 1.5-2 • C and address climate change and social economic development, SSPs have been developed with a multi-scale scenario at the global-country-region scale [28]. To achieve climate change adaptation and mitigation, some governments have implemented climate policies and other measures.…”

Archetyping shared socioeconomic pathways across scales: an application to central Asia and European case studies

“…Recent examples of the application of global SSPs include subnational and subsectoral SSP narratives for the southeastern United States (Absar and Preston 2015) and Latin America (Jones and Kok 2014), coastal SSPs (Merkens et al 2016), and more recently, deltas across West Africa and South Asia (Kebede et al 2018) and European heat-stress SSPs (Rohat et al 2019). These applications differ in sectoral and geographic scope but are methodologically similar in that they develop subglobal narratives that are "nested" within, i.e., are consistent with, the scenario logic of the global SSPs.…”