Key Innovations in Financing Nature-Based Solutions for Coastal Adaptation

The implementation of nature-based solutions (NBSs) for coastal adaptation to climate change is limited by a well-documented lack of finance. Scholars agree that financial innovation represents a solution to this problem, particularly due to its potential for mobilising private investments. It remains unclear however how exactly innovative solutions address the specific barriers found in NBS implementation and, given the distinctive local characteristics of NBSs, to what extent successful innovations can be replicated in other locations. This study addresses this issue by reviewing the literature and case studies of innovative financial solutions currently implemented in NBS projects, highlighting which financial barriers these arrangements address and which contextual conditions affect their applicability. We find that there is no “low-hanging fruit” in upscaling finance in NBSs through financial innovation. Innovative solutions are nevertheless expected to become more accessible with the increase in NBS project sizes, the increased availability of data on NBS performance, and the establishment of supportive policy frameworks. The flow of finance into NBS projects can be further enhanced through the external support of both public (de-risking and regulation) and private actors (financial expertise).This research was funded by the European Union’s Horizon 2020 research and innovation Programme, under Grant Agreement no. 101037097.European Union’s Horizon 2020 research and innovation ProgrammePeer Reviewe

Review and classification

The article processing charge was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – 491192747 and the Open Access Publication Fund of Humboldt-Universität zu Berlin.Economic decision analysis is an important tool for developing cost-efficient adaptation pathways in sectors that involve costly adaptation options, such as flood risk management. Standard economic approaches, however, do not consider learning about future changes in climate variables even though a large literature on adaptive planning emphasises the key role of learning over time, because uncertainties about climate change are substantial. An emerging, diverse and fragmented set of economic adaptive decision making approaches, coming under labels such as real-option analysis or optimal control, have started to address this challenge by including the economic valuation of learning in the economic appraisal of adaptation options through making use of so-called climate learning scenarios. We synthesise this literature and classify the climate learning scenarios applied with respect to which climate variable is learned about, which learning sources are employed, how the learning is modelled, which climate data is used for calibrating learning scenarios, which goodness of fit information is provided and how deep uncertainty is handled. Our results show that publications consider learning through observations or do not explicitly state the source of learning. Most authors generate climate learning scenarios through stochastic processes or Bayesian approaches and use climate model output from the IPCC or the UK Met Office to calibrate the learning scenarios. The reviewed literature rarely provides information on the goodness of fit of learning scenarios to the underlying climate data. We conclude that most of the methods used to generate climate learning scenarios are not well-grounded in climate science and are inadequate to represent climate uncertainty. One avenue to improve climate learning scenarios would be to combine a Bayesian approach with emulators that mimic climate model runs based on observations from future moments in time.Peer Reviewe

What drives relocation policies in the Maldives?

The predominant responses to rising sea levels are in situ adaptations. However, increasing rates of sea-level rise will render ex situ adaptations—in the form of relocations—inevitable in some low-lying coastal zones. Particularly small island states like the Maldives face this significant adaptation challenge. Here, government action is necessary to move vulnerable communities out of flood-prone areas. Yet, little empirical knowledge exists about the governance of relocations. While the literature often highlights risks and benefits of relocations, it remains unclear how governments organized relocations and what drove relocation policy. Therefore, we examined Maldivian relocation policies from 1968 to 2018 to explain government support of relocations. For this, we used a qualitative research design and extended the multiple streams approach with the theoretical lens of historical institutionalism. To gather data, we conducted semi-structured interviews (n = 23) with relocation policy experts and locals affected by relocations. Interview data was complemented with a desk review of relevant laws, historical records, and policy documents. We find 29 completed and 25 failed cases of relocations in the 50-year period. Key drivers of relocation policies are focusing events, socioeconomic development, and institutionalized island autonomy. We find that relocations were predominantly initiated as means to facilitate economic development, not as a response to rising seas or coastal risk. With current rapid economic development and strengthened democratic institutions, relocations are not considered as a policy option anymore. We conclude that implementing relocations proactively will face significant barriers in the future, which highlights the urgency of successful in situ adaptations in the Maldives.Peer Reviewe

The impacts of sea-level rise on European coasts in a 2°C world. Results and analysis of task 6.5 prepared as part of IMPACT2C: quantifying project impacts under 2°C warming

The European Union is at risk of the adverse effects of rising sea-levels, potentially leading to an increase in number of people affected by flood events and increased damage costs unless adaptation is undertaken. This research answers a question, ‘What are the impacts and costs of sea-level rise around Europe in a 2°C world?’ A 2°C world could occur rapidly under high emissions, or over much longer periods of time under climate mitigation. Climate mitigation is widely seen a way to reduce adverse risk, but in the coastal zone this is less effective and could only offer potential over very long time periods due to a time lag between atmospheric warming and oceanic response, known as the commitment to sea-level rise. As such, global mean sea-level in a 2°C world is projected to be between 0.11m (under high emissions) and 0.52m (under climate mitigation) higher than 1985-2005 levels under the HadGEM2-ES model. This makes quantifying impacts challenging.Using the Dynamic Interactive Vulnerability Assessment (DIVA) modelling framework, the number of people at risk from rising sea levels and flood costs have been analysed for scenarios of 2°C and extending up to a 5°C rise compared with pre-industrial levels in European Union coastal regions. Results indicate that following widespread European practices of continued protection, that between 5,300 and 7,000 people per year may be flooded in a 2°C world of climate mitigation – which could double if climate goes unmitigated. In a 5°C world, annual sea flood costs could be up to €1.2 billion per year, but reduce by one third under climate mitigation. The greatest costs occur around many countries surrounding the North Sea, where relatively, the EU’s smaller economies and small island states benefit most from climate mitigation.Adaptation remains particularly important, with sea dikes costing up to €3.9 billion per year in a 5°C world, decreasing by more than one sixth under climate mitigation. To achieve optimum benefits of adaptation and mitigation, it is essential that shoreline management and climate change adaptation are considered over the long time periods in which sea-level rise operates, taking into account multiple factors of coastal change. This includes a range of engineering techniques, including soft adaptation, accommodation and managed retreat, simultaneously considering wider societal needs and social acceptability of coastal change.<br/

Vulnerability to Poverty and Vulnerability to Climate Change : Conceptual Framework, Measurement and Synergies in Policy

This paper attempts to compare the concepts and metrics related to vulnerability notion as used in the poverty literature with those in the filed of climate change. Such comparison could shed light on the understanding of the perceived and real differences between the two fields and also help to identify possible policy synergies between the climate change and poverty communities. The analysis shows that while vulnerability concepts in both the disciplines are defendable, broader policy relevant statements about vulnerability could be made if the analysis clearly identifies three primitives introduced in Ionescu et al. (2006) namely, the entity that is vulnerable, the stimulus due to which the entity is vulnerable, and the preference criteria on the outcome of concern. The analysis shows significant similarities between the two fields in terms of vulnerability measurement. The link between the vulnerability metrics in the two fields can be established through the introduction of sensitivity notion. The analysis also shows that the vulnerability metrics in both fields demand a stricter restriction (namely, complete reorder) on preference criteria on the outcome(s) of concern. The analysis identifies two issues that, if addressed, could create synergies between vulnerability assessments in the climate change and the poverty communities. First, the climate change community could benefit from exploring a notion analogous to that of poverty. In development policy, the notion of poverty enables one to recognise that there is a need to focus not only on people who are likely to become poor due to some exogenous input, but also on those who already are poor (and may become even poorer). Second, it would be interesting to explore the analogous concepts of mitigation and adaptive capacity in poverty research. Similar to their use in climate research and policy, the analysis of these concepts could lead to the more explicit consideration of the multidimensional nature of both causes and outcomes of poverty, as well as of the multiple time scales on which these occur.vulnerability, poverty, Climate change, Adaptation

A typology for analysing mitigation and adaptation win-win strategies

A sustainability transition in line with achieving global climate goals requires the implementation of win-win strategies (WWS), i.e. socioeconomic activities that enable economic gains while simultaneously contributing to climate change mitigation or adaptation measures. Such strategies are discussed in a variety of scientific communities, such as sustainability science, industrial ecology and symbiosis and circular economy. However, existing analyses of win-win strategies tend to take a systems perspective, while paying less attention to the specific actors and activities, or their interconnections, which are implicated in win-win strategies. Moreover, they hardly address adaptation WWS. To address these gaps and support the identification and enhancement of WWS for entrepreneurs and policy-makers, we propose a typology of WWS based on the concept of a value-consumption chain, which typically connects several producers with at least one consumer of a good or service. A consideration of these connections allows an evaluation of economic effects in a meso-economic perspective. We distinguish 34 different types of WWS of companies, households and the state, for which 23 real-world examples are identified. Further, contrary to prevailing views on the lack of a business case for adaptation, we do identify real-world adaptation WWS, though they remain underrepresented compared with mitigation WWS. Our typology can be used as an entry point for transdisciplinary research integrating assessment of individual transformative socioeconomic activities and highly aggregated approaches assessing, e.g. the macro-economic effects of WWS.Horizon 2020 Framework Programme ()Peer Reviewe

Future urban development exacerbates coastal exposure in the Mediterranean

Changes in the spatial patterns and rate of urban development will be one of the main determinants of future coastal flood risk. Existing spatial projections of urban extent are, however, often available at coarse spatial resolutions, local geographical scales or for short time horizons, which limits their suitability for broad-scale coastal flood impact assessments. Here, we present a new set of spatially explicit projections of urban extent for ten countries in the Mediterranean, consistent with the Shared Socioeconomic Pathways (SSPs). To model plausible future urban development, we develop an Urban Change Model, which uses input variables such as elevation, population density or road network and an artificial neural network to project urban development on a regional scale. The developed future projections for the five SSPs indicate that accounting for the spatial patterns of urban development can lead to significant differences in the assessment of future coastal urban exposure. The increase in exposure in the Extended Low Elevation Coastal Zone (E-LECZ = area below 20 m of elevation) until 2100 can vary, by up to 104%, depending on the urban development scenario chosen. This finding highlights that accounting for urban development in long-term adaptation planning, e.g. in the form of land-use planning, can be an effective measure for reducing future coastal flood risk on a regional scale

Gridded population projections for the coastal zone under the Shared Socioeconomic Pathways

AbstractExisting quantifications of the Shared Socioeconomic Pathways (SSP) used for climate impact assessment do not account for subnational population dynamics such as coastward-migration that can be critical for coastal impact assessment. This paper extends the SSPs by developing spatial projections of global coastal population distribution for the five basic SSPs. Based on a series of coastal migration drivers we develop coastal narratives for each SSP. These narratives account for differences in coastal and inland population developments in urban and rural areas. To spatially distribute population, we use the International Institute for Applied Systems Analysis (IIASA) national population and urbanisation projections and employ country-specific growth rates, which differ for coastal and inland as well as for urban and rural regions, to project coastal population for each SSP. These rates are derived from spatial analysis of historical population data and adjusted for each SSP based on the coastal narratives. Our results show that, compared to the year 2000 (638 million), the population living in the Low Elevated Coastal Zone (LECZ) increases by 58% to 71% until 2050 and exceeds one billion in all SSPs. By the end of the 21st century, global coastal population declines to 830–907 million in all SSPs except for SSP3, where coastal population growth continues and reaches 1.184 billion. Overall, the population living in the LECZ is higher by 85 to 239 million compared to the original IIASA projections. Asia expects the highest absolute growth (238–303 million), Africa the highest relative growth (153% to 218%). Our results highlight regions where high coastal population growth is expected and will therefore face an increased exposure to coastal flooding

Global-scale analysis of socioeconomic impacts of coastal flooding over the 21st century

Building on a global database of projected extreme coastal flooding over the coming century, an extensive analysis that accounts for both existing levels of coastal defences (structural measures) and two scenarios for future changes in defence levels is undertaken to determine future expected annual people affected (EAPA) and expected annual damage (EAD). A range of plausible future climate change scenarios is considered along with narratives for socioeconomic change. We find that with no further adaptation, global EAPA could increase from 34M people/year in 2015 to 246M people/year by 2100. Global EAD could increase from 0.3% of global GDP today to 2.9% by 2100. If, however, coastal defences are increased at a rate which matches the projected increase in extreme sea level, by 2100, the total EAPA is reduced to 119M people/year and the EAD will be reduced by a factor of almost three to 1.1% of GDP. The impacts of such flooding will disproportionately affect the developing world. By 2100, Asia, West Africa and Egypt will be the regions most impacted. If no adaptation actions are taken, many developing nations will experience EAD greater than 5% of GDP, whilst almost all developed nations will experience EAD less than 3% of GDP