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

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 DECCMA1 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.

A framework for identifying and selecting long term adaptation policy directions for deltas.

Deltas are precarious environments experiencing significant biophysical, and socio-economic changes with the ebb and flow of seasons (including with floods and drought), with infrastructural developments (such as dikes and polders), with the movement of people, and as a result of climate and environmental variability and change. Decisions are being taken about the future of deltas and about the provision of adaptation investment to enable people and the environment to respond to the changing climate and related changes. The paper presents a framework to identify options for, and trade-offs between, long term adaptation strategies in deltas. Using a three step process, we: (1) identify current policy-led adaptations actions in deltas by conducting literature searches on current observable adaptations, potential transformational adaptations and government policy; (2) develop narratives of future adaptation policy directions that take into account investment cost of adaptation and the extent to which significant policy change/political effort is required; and (3) explore trade-offs that occur within each policy direction using a subjective weighting process developed during a collaborative expert workshop. We conclude that the process of developing policy directions for adaptation can assist policy makers in scoping the spectrum of options that exist, while enabling them to consider their own willingness to make significant policy changes within the delta and to initiate transformative change.

Adaptation and development trade-offs: fluvial sediment deposition and the sustainability of rice-cropping in An Giang Province, Mekong Delta.

Deltas around the globe are facing a multitude of intensifying environmental change and development-linked pressures. One key concern is the reduction in the quantity of suspended sediment reaching and building floodplains. Sediment deposition provides multiple services to deltaic social-ecological systems, in particular, countering the subsidence of the delta-body, and providing plentiful nutrients. Experiencing particularly rapid change is the Vietnamese Mekong Delta (VMD). In An Giang Province an increasing number of high dyke rings, which exclude the flood and facilitate triple rice-cropping, simultaneously prevent much of the sediment load from reaching the floodplain. This paper explores the trade-offs implicit in the decision to shift from (i) doublecropping (higher sediment deposition) to (ii) triple cropping (lower sediment deposition) by asking: what is the impact of the shift on VMD farmers? Is it sustainable? And what is the significance of the associated sediment exclusion? A novel survey of An Giang rice farmers was conducted, investigating key agricultural practices, and uniquely, the farmers' estimates of annual sediment deposition depth. The survey elicits some key changes under the adapted system (ii), particularly, unsustainable trajectories in the yield to fertiliser ratio which penalise land-poor farmers. Furthermore, the value (to farmers) of the sediment contribution to agricultural fertilisation which is lost due to triple-cropping is estimated at USD 15 (±5) million annually. We argue that our growing understanding of the importance of sediment in the deltaic social-ecological system may be revealing an emergent risk; arising from conflicting long and short-term adaptation and agricultural development objectives.

Presenting Triple-Wins? Assessing Projects That Deliver Adaptation, Mitigation and Development Co-benefits in Rural Sub-Saharan Africa.

The concept of climate compatible development (CCD) is increasingly employed by donors and policy makers seeking 'triple-wins' for development, adaptation and mitigation. While CCD rhetoric is becoming more widespread, analyses drawing on empirical cases that present triple-wins are sorely lacking. We address this knowledge gap. Drawing on examples in rural sub-Saharan Africa, we provide the first glimpse into how projects that demonstrate triple-win potential are framed and presented within the scientific literature. We identify that development projects are still commonly evaluated in terms of adaptation or mitigation benefits. Few are framed according to their benefits across all three dimensions. Consequently, where triple-wins are occurring, they are likely to be under-reported. This has important implications, which underestimates the co-benefits that projects can deliver. A more robust academic evidence base for the delivery of triple-wins is necessary to encourage continued donor investment in activities offering the potential to deliver CCD.

What do we know about UK household adaptation to climate change? A systematic review.

The UK Government's first National Adaptation Programme seeks to create a 'climate-ready society' capable of making well-informed and far-sighted decisions to address risks and opportunities posed by a changing climate, where individual households are expected to adapt when it is in their interest to do so. How, and to what extent, households are able to do this remains unclear. Like other developed countries, research on UK adaptation has focused predominately on public and private organisations. To fill that gap, a systematic literature review was conducted to understand what actions UK households have taken in response to, or in anticipation of, a changing climate; what drives or impedes these actions; and whether households will act autonomously. We found that UK households struggle to build long-term adaptive capacity and are reliant upon traditional reactive coping responses. Of concern is that these coping responses are less effective for some climate risks (e.g. flooding); cost more over the long-term; and fail to create household capacity to adapt to other stresses. While low-cost, low-skill coping responses were already being implemented, the adoption of more permanent physical measures, behavioural changes, and acceptance of new responsibilities are unlikely to happen autonomously without further financial or government support. If public policy on household adaptation to climate change is to be better informed than more high-quality empirical research is urgently needed.

Scenario-based stakeholder engagement: incorporating stakeholders preferences into coastal planning for climate change.

Climate change poses many challenges for ecosystem and resource management. In particular, coastal planners are struggling to find ways to prepare for the potential impacts of future climate change while dealing with immediate pressures. Decisions on how to respond to future risks are complicated by the long time horizons and the uncertainty associated with the distribution of impacts. Existing coastal zone management approaches in the UK either do not adequately incorporate changing stakeholder preferences, or effectively ensure that stakeholders are aware of the trade-offs inherent in any coastal management decision. Using a novel method, scenario-based stakeholder engagement, which brings together stakeholder analysis, climate change management scenarios and deliberative techniques, the necessary trade-offs associated with long term coastal planning are explored. The method is applied to two case studies of coastal planning in Christchurch Bay on the south coast of England and the Orkney Islands off the north coast of Scotland. A range of conflicting preferences exist on the ideal governance structure to manage the coast under different climate change scenarios. In addition, the results show that public understanding of the trade-offs that have to be made is critical in gaining some degree of public support for long term coastal decision-making. We conclude that scenario-based stakeholder engagement is a useful tool to facilitate coastal management planning that takes into account the complexities and challenges of climate change, and could be used in conjunction with existing approaches such as the Shoreline Management Planning process.

Eliciting information from experts on the likelihood of rapid climate change.

The threat of so-called rapid or abrupt climate change has generated considerable public interest because of its potentially significant impacts. The collapse of the North Atlantic Thermohaline Circulation or the West Antarctic Ice Sheet, for example, would have potentially catastrophic effects on temperatures and sea level, respectively. But how likely are such extreme climatic changes? Is it possible actually to estimate likelihoods? This article reviews the societal demand for the likelihoods of rapid or abrupt climate change, and different methods for estimating likelihoods: past experience, model simulation, or through the elicitation of expert judgments. The article describes a survey to estimate the likelihoods of two characterizations of rapid climate change, and explores the issues associated with such surveys and the value of information produced. The surveys were based on key scientists chosen for their expertise in the climate science of abrupt climate change. Most survey respondents ascribed low likelihoods to rapid climate change, due either to the collapse of the Thermohaline Circulation or increased positive feedbacks. In each case one assessment was an order of magnitude higher than the others. We explore a high rate of refusal to participate in this expert survey: many scientists prefer to rely on output from future climate model simulations.