• Energy Research

AbstractAn increasing number of research programs seek to support adaptation to climate change through the engagement of large‐scale transdisciplinary networks that span countries and continents. While transdisciplinary research processes have been a topic of reflection, practice, and refinement for some time, these trends now mean that the global change research community needs to reflect and learn how to pursue collaborative research on a large scale. This paper shares insights from a seven‐year climate change adaptation research program that supports collaboration between more than 450 researchers and practitioners across four consortia and 17 countries. The experience confirms the importance of attention to careful design for transdisciplinary collaboration, but also highlights that this alone is not enough. The success of well‐designed transdisciplinary research processes is also strongly influenced by relational and systemic features of collaborative relationships. Relational features include interpersonal trust, mutual respect, and leadership styles, while systemic features include legal partnership agreements, power asymmetries between partners, and institutional values and cultures. In the new arena of large‐scale collaborative science efforts, enablers of transdisciplinary collaboration include dedicated project coordinators, leaders at multiple levels, and the availability of small amounts of flexible funds to enable nimble responses to opportunities and unexpected collaborations.

AbstractBangladesh is one of the most climate-sensitive countries globally, creating significant challenges for future development. Here we apply an integrated assessment model — Delta Dynamic Integrated Emulator Model (ΔDIEM) — to the south-west coastal zone of Bangladesh to explore the outcomes of four contrasting and plausible development trajectories under different climate and socio-economic scenarios: (1) embankment rehabilitation; (2) build elevation via controlled sedimentation; (3) planned migration (managed retreat) and (4) ‘do nothing’ (unplanned migration and abandonment). Embankment rehabilitation reduces flood risk, but at a high economic cost and enhancing waterlogging. Planned and unplanned migration combined with limited infrastructure management and governance both result in significant abandonment. Building elevation through sedimentation has the potential for increased environmental and economic sustainability but raises equity issues. Poverty and inequality persist across all scenarios, and outmigration from the coastal zone continues, although the magnitude is sensitive to assumptions about sea-level rise, socio-economic development and development trajectory. Integrated assessment tools linking the environment, people and policy choices, such as the ΔDIEM used here, highlight the complex interactions occurring in a dynamic delta environment. Such analysis supports informed management, development and adaptation.

The impacts of climate change on people's livelihoods have been widely documented. It is expected that climate and environmental change will hamper poverty reduction, or even exacerbate poverty in some or all of its dimensions. Changes in the biophysical environment, such as droughts, flooding, water quantity and quality, and degrading ecosystems, are expected to affect opportunities for people to generate income. These changes, combined with a deficiency in coping strategies and innovation to adapt to particular climate change threats, are in turn likely to lead to increased economic and social vulnerability of households and communities, especially amongst the poorest.

As the scientific consensus concerning global climate change has increased in recent decades, research on potential impacts of climate change on water resources has been given high importance. However in Sub-Saharan Africa, few studies have fully evaluated the potential implications of climate change to their water resource systems. The Volta River is one of the major rivers in Africa covering six riparian countries (mainly Ghana and Burkina Faso). It is a principal water source for approximately 24 million people in the region. The catchment is primarily agricultural providing food supplies to rural areas, demonstrating the classic water, food, energy nexus. In this study an Integrated Catchment Model (INCA) was applied to the whole Volta River system to simulate flow in the rivers and at the outlet of the artificial Lake Volta. High-resolution climate scenarios downscaled from three different Global Climate Models (CNRM-CM5, HadGEM2-ES and CanESM2), have been used to drive the INCA model and to assess changes in flow by 2050s and 2090s under the high climate forcing scenario RCP8.5. Results show that peak flows during the monsoon months could increase into the future. The duration of high flow could become longer compared to the recent condition. In addition, we considered three different socio-economic scenarios. As an example, under the combined impact from climate change from downscaling CNRM-CM5 and medium+ (high economic growth) socio-economic changes, the extreme high flows (Q5) of the Black Volta River are projected to increase 11% and 36% at 2050s and 2090s, respectively. Lake Volta outflow would increase +1% and +5% at 2050s and 2090s, respectively, under the same scenario. The effects of changing socio-economic conditions on flow are minor compared to the climate change impact. These results will provide valuable information assisting future water resource development and adaptive strategies in the Volta Basin.

Regular sediment inputs are required for deltas to maintain their surface elevation relative to sea level, which is important for avoiding salinization, erosion, and flooding. However, fluvial sediment inputs to deltas are being threatened by changes in upstream catchments due to climate and land use change and, particularly, reservoir construction. In this research, the global hydrogeomorphic model WBMsed is used to project and contrast 'pristine' (no anthropogenic impacts) and 'recent' historical fluvial sediment delivery to the Ganges-Brahmaputra-Meghna, Mahanadi, and Volta deltas. Additionally, 12 potential future scenarios of environmental change comprising combinations of four climate and three socioeconomic pathways, combined with a single construction timeline for future reservoirs, were simulated and analysed. The simulations of the Ganges-Brahmaputra-Meghna delta showed a large decrease in sediment flux over time, regardless of future scenario, from 669 Mt/a in a 'pristine' world, through 566 Mt/a in the 'recent' past, to 79-92 Mt/a by the end of the 21st century across the scenarios (total average decline of 88%). In contrast, for the Mahanadi delta the simulated sediment delivery increased between the 'pristine' and 'recent' past from 23 Mt/a to 40 Mt/a (+77%), and then decreased to 7-25 Mt/a by the end of the 21st century. The Volta delta shows a large decrease in sediment delivery historically, from 8 to 0.3 Mt/a (96%) between the 'pristine' and 'recent' past, however over the 21st century the sediment flux changes little and is predicted to vary between 0.2 and 0.4 Mt/a dependent on scenario. For the Volta delta, catchment management short of removing or re-engineering the Volta dam would have little effect, however without careful management of the upstream catchments these deltas may be unable to maintain their current elevation relative to sea level, suggesting increasing salinization, erosion, flood hazards, and adaptation demands.

Tides are a key component in coastal extreme water levels. Possible changes in the tides caused by mean sea-level rise (SLR) are therefore of importance in the analysis of coastal flooding, as well as many other applications. We investigate the effect of future SLR on the tides globally using a fully global forward tidal model: OTISmpi. Statistical comparisons of the modelled and observed tidal solutions demonstrate the skill of the refined model setup with no reliance on data assimilation. We simulate the response of the four primary tidal constituents to various SLR scenarios. Particular attention is paid to future changes at the largest 136 coastal cities, where changes in water level would have the greatest impact. Spatially uniform SLR scenarios ranging from 0.5 to 10 m with fixed coastlines show that the tidal amplitudes in shelf seas globally respond strongly to SLR with spatially coherent areas of increase and decrease. Changes in the M2 and S2 constituents occur globally in most shelf seas, whereas changes in K1 and O1 are confined to Asian shelves. With higher SLR tidal changes are often not proportional to the SLR imposed and larger portions of mean high water (MHW) changes are above proportional. Changes in MHW exceed ±10% of the SLR at ~10% of coastal cities. SLR scenarios allowing for coastal recession tend increasingly to result in a reduction in tidal range. The fact that the fixed and recession shoreline scenarios result mainly in changes of opposing sign is explained by the effect of the perturbations on the natural period of oscillation of the basin. Our results suggest that coastal management strategies could influence the sign of the tidal amplitude change. The effect of a spatially varying SLR, in this case fingerprints of the initial elastic response to ice mass loss, modestly alters the tidal response with the largest differences at high latitudes.