Getting the message right on nature‐based solutions to climate change

Nature‐based solutions (NbS)—solutions to societal challenges that involve working with nature—have recently gained popularity as an integrated approach that can address climate change and biodiversity loss, while supporting sustainable development. Although well‐designed NbS can deliver multiple benefits for people and nature, much of the recent limelight has been on tree planting for carbon sequestration. There are serious concerns that this is distracting from the need to rapidly phase out use of fossil fuels and protect existing intact ecosystems. There are also concerns that the expansion of forestry framed as a climate change mitigation solution is coming at the cost of carbon rich and biodiverse native ecosystems and local resource rights. Here, we discuss the promise and pitfalls of the NbS framing and its current political traction, and we present recommendations on how to get the message right. We urge policymakers, practitioners and researchers to consider the synergies and trade‐offs associated with NbS and to follow four guiding principles to enable NbS to provide sustainable benefits to society: (1) NbS are not a substitute for the rapid phase out of fossil fuels; (2) NbS involve a wide range of ecosystems on land and in the sea, not just forests; (3) NbS are implemented with the full engagement and consent of Indigenous Peoples and local communities in a way that respects their cultural and ecological rights; and (4) NbS should be explicitly designed to provide measurable benefits for biodiversity. Only by following these guidelines will we design robust and resilient NbS that address the urgent challenges of climate change and biodiversity loss, sustaining nature and people together, now and into the future.

Socio-economic outcomes of ecological infrastructure investments

Ecological infrastructure refers to naturally functioning ecosystems that deliver valuable services to people, such as filtered water and disaster risk reduction. With natural resources becoming scarcer, there is a growing interest in reinvesting in naturally functioning ecosystems in the form of ecological infrastructure, with the assumption that ecological infrastructure complements engineered infrastructure. In many low- and middle-income countries, ecological infrastructure interventions are seen as a key strategy to simultaneously alleviate poverty and improve ecosystem functioning. However, the socio-economic outcomes of ecological infrastructure investments remain poorly documented. We address this knowledge gap by synthesizing research (n = 53 cases) that analyses how ecological infrastructure investments affect ten different socio-economic dimensions, such as income and food security in low- and middle-income countries. We find that ecological infrastructure investments primarily lead to positive outcomes for short-term income and natural capital, whereas positive outcomes for other socio-economic dimensions are less frequently observed. Cases with a high degree of participant involvement in the early implementation of ecological infrastructure investments are significantly more likely to capture positive outcomes across a variety of socio-economic dimensions. Analogously, cases spanning multiple methods – rather than adopting either a qualitative or a quantitative approach – report positive outcomes across more dimensions.

A review of nature-based solutions for urban water management in European circular cities: a critical assessment based on case studies and literature

Nature-based solutions (NBS) can protect, manage and restore natural or modified ecosystems. They are a multidisciplinary, integrated approach to address societal challenges and some natural hazards effectively and adaptively, simultaneously providing human well-being and biodiversity benefits. NBS applications can be easily noticed in circular cities, establishing an urban system that is regenerative and accessible. This paper aims to offer a review on NBS for urban water management from the literature and some relevant projects running within the COST Action ‘Implementing nature-based solutions for creating a resourceful circular city’. The method used in the study is based on a detailed tracking of specific keywords in the literature using Google Scholar, ResearchGate, Academia.edu, ScienceDirect and Scopus. Based on this review, three main applications were identified: (i) flood and drought protection; (ii) the water-food-energy nexus; and (iii) water purification. The paper shows that NBS provide additional benefits, such as improving water quality, increasing biodiversity, obtaining social co-benefits, improving urban microclimate, and the reduction of energy consumption by improving indoor climate. The paper concludes that a systemic change to NBS should be given a higher priority and be preferred over conventional water infrastructure.

Pitfalls of Tree Planting Show Why We Need People-Centered Natural Climate Solutions

Scientists, corporations, mystics, and movie stars have convinced policymakers around the world that a massive campaign to plant trees
should be an essential element of global climate policy. Public dialogue
has emphasized potential benefits of tree planting while downplaying
pitfalls and limitations that are well established by social and ecological
research. We argue that if natural climate solutions are to succeed while
economies decarbonize (Griscom et al. 2017), policymakers must recognize and avoid the expense, risk, and damage that poorly designed and hastily implemented tree plantings impose on ecosystems and people.

We propose that people-centered climate policies should be developed
that support the social, economic, and political conditions that are compatible with the conservation of Earth’s diversity of terrestrial ecosystems. Such a shift in focus, away from tree planting and toward people and ecosystems, must be rooted in the understanding that natural climate solutions can only be effective if they respond to the needs of the rural and indigenous people who manage ecosystems for their livelihoods.

To motivate this shift in focus, we highlight ten pitfalls and misperceptions that arise when large-scale tree planting campaigns fail to acknowledge the social and ecological complexities of the landscapes they aim to transform. We then describe more ecologically effective and socially just strategies to improve climate mitigation efforts.

Predicting the long-term social and ecological impacts of tree-planting programs: Evidence from northern India

Planting trees has long been a major forest improvement and management activity globally. Forest plantations take years, even decades to mature and establish. Yet most national and international projects to support plantations are of relatively short duration, which presents a major challenge to near-term accountability as well as assessment of longer-term social and ecological impacts. Here, we address this challenge by identifying and empirically validating a set of predictive proxy indicators (PPIs)—measures on key variables taken during program implementation that are predictive of longer-term impacts—for community-oriented tree-planting efforts in northern India. Using process-tracing and qualitative comparative analysis, we find that clusters of PPIs explained vegetation growth trajectories and other outcomes over more than a decade in 23 randomly selected public forest plantations in Kangra district, Himachal Pradesh. PPIs relating to property rights and local livelihood benefits, community-led monitoring and enforcement, and seedling survival rate, together, were associated with successful long-term forest plantation outcomes, including more tree cover and socio-economic benefits for local communities. The causal pathways identified in this study suggest that measuring and comparing indicator values in specific spatial and temporal contexts can help to assess the likelihood and directionality of the long-term social and ecological impacts of forest plantations. In addition to the empirical contribution it makes, this study also demonstrates a novel approach to understanding long-term impacts of public forest plantations relevant to country contexts around the world.

Agricultural diversification promotes multiple ecosystem services without compromising yield

Enhancing biodiversity in cropping systems is suggested to promote ecosystem services, thereby reducing dependency on agronomic inputs while maintaining high crop yields. We assess the impact of several diversification practices in cropping systems on above- and belowground biodiversity and ecosystem services by reviewing 98 meta-analyses and performing a second-order meta-analysis based on 5160 original studies comprising 41,946 comparisons between diversified and simplified practices. Overall, diversification enhances biodiversity, pollination, pest control, nutrient cycling, soil fertility, and water regulation without compromising crop yields. Practices targeting aboveground biodiversity boosted pest control and water regulation, while those targeting belowground biodiversity enhanced nutrient cycling, soil fertility, and water regulation. Most often, diversification practices resulted in win-win support of services and crop yields. Variability in responses and occurrence of trade-offs highlight the context dependency of outcomes. Widespread adoption of diversification practices shows promise to contribute to biodiversity conservation and food security from local to global scales.

Evaluating nature-based solutions for climate mitigation and conservation requires comprehensive carbon accounting

Nature-based solutions (NbS) can address climate change, biodiversity loss, human well-being and their interactions in an integrated way. A major barrier to achieving this is the lack of comprehensiveness in current carbon accounting which has focused on flows rather than stocks of carbon and led to perverse outcomes. We propose a new comprehensive approach to carbon accounting based on the whole carbon cycle, covering both stocks and flows, and linking changes due to human activities with responses in the biosphere and atmosphere. We identify enhancements to accounting, namely; inclusion of all carbon reservoirs, changes in their condition and stability, disaggregated flows, and coverage of all land areas. This comprehensive approach recognises that both carbon stocks (as storage) and carbon flows (as sequestration) contribute to the ecosystem service of global climate regulation. In contrast, current ecosystem services measurement and accounting commonly use only carbon sequestration measured as net flows, while greenhouse gas inventories use flows from sources to sinks. This flow-based accounting has incentivised planting and maintaining young forests with high carbon uptake rates, resulting, perversely, in failing to reveal the greater mitigation benefit from protecting larger, more stable and resilient carbon stocks in natural forests. We demonstrate the benefits of carbon storage and sequestration for climate mitigation, in theory as ecosystem services within an ecosystem accounting framework, and in practice using field data that reveals differences in results between accounting for stocks or flows. Our proposed holistic and comprehensive carbon accounting makes transparent the benefits, trade-offs and shortcomings of NbS actions for climate mitigation and sustainability outcomes. Adopting this approach is imperative for revision of ecosystem accounting systems under the System of Environmental-Economic Accounting and contributing to evidence-based decision-making for international conventions on climate (UNFCCC), biodiversity (CBD) and sustainability (SDGs).

Transdisciplinary science for improved conservation outcomes

Major advances in biology and ecology have sharpened our understanding of what the goals of biodiversity conservation might be, but less progress has been made on how to achieve conservation in the complex, multi-sectoral world of human affairs. The failure to deliver conservation outcomes is especially severe in the rapidly changing landscapes of tropical low-income countries. We describe five techniques we have used to complement and strengthen long-term attempts to achieve conservation outcomes in the landscapes and seascapes of such regions; these are complex social-ecological systems shaped by interactions between biological, ecological and physical features mediated by the actions of people. Conservation outcomes occur as a result of human decisions and the governance arrangements that guide change. However, much conservation science in these countries is not rooted in a deep understanding of how these social-ecological systems work and what really determines the behaviour of the people whose decisions shape the future of landscapes. We describe five scientific practices that we have found to be effective in building relationships with actors in landscapes and influencing their behaviour in ways that reconcile conservation and development. We have used open-ended inductive enquiry, theories of change, simulation models, network analysis and multi-criteria analysis. These techniques are all widely known and well tested, but seldom figure in externally funded conservation projects. We have used these techniques to complement and strengthen existing interventions of international conservation agencies. These five techniques have proven effective in achieving deeper understanding of context, engagement with all stakeholders, negotiation of shared goals and continuous learning and adaptation.

Ten golden rules for reforestation to optimize carbon sequestration, biodiversity recovery and livelihood benefits

Urgent solutions to global climate change are needed. Ambitious tree‐planting initiatives, many already underway, aim to sequester enormous quantities of carbon to partly compensate for anthropogenic CO2 emissions, which are a major cause of rising global temperatures. However, tree planting that is poorly planned and executed could actually increase CO2 emissions and have long‐term, deleterious impacts on biodiversity, landscapes and livelihoods. Here, we highlight the main environmental risks of large‐scale tree planting and propose 10 golden rules, based on some of the most recent ecological research, to implement forest ecosystem restoration that maximizes rates of both carbon sequestration and biodiversity recovery while improving livelihoods. These are as follows: (1) Protect existing forest first; (2) Work together (involving all stakeholders); (3) Aim to maximize biodiversity recovery to meet multiple goals; (4) Select appropriate areas for restoration; (5) Use natural regeneration wherever possible; (6) Select species to maximize biodiversity; (7) Use resilient plant material (with appropriate genetic variability and provenance); (8) Plan ahead for infrastructure, capacity and seed supply; (9) Learn by doing (using an adaptive management approach); and (10) Make it pay (ensuring the economic sustainability of the project). We focus on the design of long‐term strategies to tackle the climate and biodiversity crises and support livelihood needs. We emphasize the role of local communities as sources of indigenous knowledge, and the benefits they could derive from successful reforestation that restores ecosystem functioning and delivers a diverse range of forest products and services. While there is no simple and universal recipe for forest restoration, it is crucial to build upon the currently growing public and private interest in this topic, to ensure interventions provide effective, long‐term carbon sinks and maximize benefits for biodiversity and people.

A conceptual model of the social–ecological system of nature-based solutions in urban environments

This article provides a perspective on nature-based solutions. First, the argument is developed that nature-based solutions integrate social and ecological systems. Then, theoretical considerations relating to relational values, multifunctionality, transdisciplinarity, and polycentric governance are briefly outlined. Finally, a conceptual model of the social–ecological system of nature-based solutions is synthesised and presented. This conceptual model comprehensively defines the social and ecological external and internal systems that make up nature-based solutions, and identifies theoretical considerations that need to be addressed at different stages of their planning and implementation The model bridges the normative gaps of existing nature-based solution frameworks and could be used for consistent, comprehensive, and transferable comparisons internationally. The theoretical considerations addressed in this article inform practitioners, policymakers, and researchers about the essential components of nature-based solutions. The conceptual model can facilitate the identification of social and ecological interconnections within nature-based solutions and the range of stakeholders and disciplines involved.

The economic costs of planting, preserving, and managing the world’s forests to mitigate climate change

Forests are critical for stabilizing our climate, but costs of mitigation over space, time, and stakeholder group remain uncertain. Using the Global Timber Model, we project mitigation potential and costs for four abatement activities across 16 regions for carbon price scenarios of $5–$100/tCO2. We project 0.6–6.0 GtCO2 yr−1 in global mitigation by 2055 at costs of 2–393 billion USD yr−1, with avoided tropical deforestation comprising 30–54% of total mitigation. Higher prices incentivize larger mitigation proportions via rotation and forest management activities in temperate and boreal biomes. Forest area increases 415–875 Mha relative to the baseline by 2055 at prices $35–$100/tCO2, with intensive plantations comprising <7% of this increase. Mitigation costs borne by private land managers comprise less than one-quarter of total costs. For forests to contribute ~10% of mitigation needed to limit global warming to 1.5 °C, carbon prices will need to reach $281/tCO2 in 2055.

Anthropogenic modification of forests means only 40% of remaining forests have high ecosystem integrity

Many global environmental agendas, including halting biodiversity loss, reversing land degradation, and limiting climate change, depend upon retaining forests with high ecological integrity, yet the scale and degree of forest modification remain poorly quantified and mapped. By integrating data on observed and inferred human pressures and an index of lost connectivity, we generate a globally consistent, continuous index of forest condition as determined by the degree of anthropogenic modification. Globally, only 17.4 million km2 of forest (40.5%) has high landscape-level integrity (mostly found in Canada, Russia, the Amazon, Central Africa, and New Guinea) and only 27% of this area is found in nationally designated protected areas. Of the forest inside protected areas, only 56% has high landscape-level integrity. Ambitious policies that prioritize the retention of forest integrity, especially in the most intact areas, are now urgently needed alongside current efforts aimed at halting deforestation and restoring the integrity of forests globally.

The greenhouse gas offset potential from seagrass restoration

Awarding CO2 offset credits may incentivize seagrass restoration projects and help reverse greenhouse gas (GHG) emissions from global seagrass loss. However, no study has quantified net GHG removal from the atmosphere from a seagrass restoration project, which would require coupled Corg stock and GHG flux enhancement measurements, or determined whether the creditable offset benefit can finance the restoration. We measured all of the necessary GHG accounting parameters in the 7-km2 Zostera marina (eelgrass) meadow in Virginia, U.S.A., part of the largest, most cost-effective meadow restoration to date, to provide the first seagrass offset finance test-of-concept. Restoring seagrass removed 9,600 tCO2 from the atmosphere over 15 years but also enhanced both CH4 and N2O production, releasing 950 tCO2e. Despite tripling the N2O flux to 0.06 g m−2 yr−1 and increasing CH4 8-fold to 0.8 g m−2 yr−1, the meadow now offsets 0.42 tCO2e ha−1 yr−1, which is roughly equivalent to the seagrass sequestration rate for GHG inventory accounting but lower than the rates for temperate and tropical forests. The financial benefit for this highly successful project, $87 K at $10 MtCO2e−1, defrays ~10% of the restoration cost. Managers should also consider seagrass co-benefits, which provide additional incentives for seagrass restoration.

Strengthening synergies: how action to achieve post-2020 global biodiversity conservation targets can contribute to mitigating climate change

The climate and biodiversity crises are fundamentally connected and more integrated approaches are needed to address them effectively. To directly tackle the interconnected factors behind them, actions which
capitalize on the contributions of nature, commonly known as Naturebased Solutions (NbS), can play a more central role. The one-year delay in the 2020 Conferences of Parties to the UNFCCC and the CBD caused by the COVID-19 crisis provides a unique opportunity to bring new scientific advances to inform and strengthen the links between both international agendas and their national implementation. To facilitate the alignment and better understand the potential synergies between these agendas, there is a need to assess the role that achieving biodiversity conservation targets can play in efforts to mitigate climate change. This report presents the first results of ongoing research aiming to inform progress by making explicit and quantifying the role that achieving biodiversity conservation targets can play in securing the emissions reductions needed to meet the objectives of the Paris Agreement. This report, the first output of this effort, looks at the carbon stocks associated with areas identified as possible priorities to meet proposed global biodiversity conservation targets.

The analysis presented here identifies the regions where global action will deliver the most to achieve post-2020 biodiversity conservation goals and mitigate climate change. It shows that the strategic choice of areas to be managed for conservation, increasing such areas to 30% of land globally,
could safeguard more than 500 gigatons of carbon. When prioritizing
areas for conservation management, taking account of biodiversity and
carbon together can secure 95% of the biodiversity benefits and nearly
80% of the carbon stock that could be obtained by prioritizing based on
either value alone. [Continued]

Mapping carbon accumulation potential from global natural forest regrowth

To constrain global warming, we must strongly curtail greenhouse gas emissions and capture excess atmospheric carbon dioxide. Regrowing natural forests is a prominent strategy for capturing additional carbon, but accurate assessments of its potential are limited by uncertainty and variability in carbon accumulation rates. To assess why and where rates differ, here we compile georeferenced measurements of carbon accumulation. Climatic factors explain variation in rates better than land-use history, so we combine the field measurements with 66 environmental covariate layers to create a global, one-kilometre-resolution map of potential aboveground carbon accumulation rates for the first 30 years of natural forest regrowth. This map shows over 100-fold variation in rates across the globe, and indicates that default rates from the Intergovernmental Panel on Climate Change (IPCC) may underestimate aboveground carbon accumulation rates by 32 per cent on average and do not capture eight-fold variation within ecozones. Conversely, we conclude that maximum climate mitigation potential from natural forest regrowth is 11 per cent lower than previously reported owing to the use of overly high rates for the location of potential new forest. Although our data compilation includes more studies and sites than previous efforts, our results depend on data availability, which is concentrated in ten countries, and data quality, which varies across studies. However, the plots cover most of the environmental conditions across the areas for which we predicted carbon accumulation rates (except for northern Africa and northeast Asia). We therefore provide a robust and globally consistent tool for assessing natural forest regrowth as a climate mitigation strategy.

Evaluating Policy and Legal Frameworks of Urban Green Infrastructure Development in Ethiopia

Policy monitoring and evaluation are important elements of the policy cycle, this help to initiate policy-makers to assess the proper implementation and adjust it as appropriate. This paper aims to evaluate the existing policy, strategies, and institutional arrangement on the development of urban green infrastructure in the three study areas; namely Hawassa, Wolayita Sodo, and Bodity town. Analyzing policy documents, key informant interview, and questionnaire survey were used to collect the required data. Descriptive statistics and policy analysis were also used to analyze the collected data from different sources. The study revealed that different strategies and standards were developed by the federal government, but it is not practically exercised at the regional and local level. The majority of government officials and experts agreed that existing policies and strategies related to UGI is not properly implemented. On the other hand, lack of policy and strategies are the major limitation in the development and management of UGI. Almost majority of the respondents confirmed that weak institutional arrangement has contributed to the poor implementation of UGI development. Lack of attention and awareness, the weak institutional arrangement is the main responsible factors for the absence of proper policy and poor implementation of strategies concerning UGI. Thus, actions needed for all the development of proper policies and strategies to improve UGI development.

Conversion of coastal wetlands, riparian wetlands and peatlands increases greenhouse gas emissions: A global meta‐analysis

Land‐use/land‐cover change (LULCC) often results in degradation of natural wetlands and affects the dynamics of greenhouse gases (GHGs). However, the magnitude of changes in GHG emissions from wetlands undergoing various LULCC types remains unclear. We conducted a global meta‐analysis with a database of 209 sites to examine the effects of LULCC types of constructed wetlands (CWs), croplands (CLs), aquaculture ponds (APs), drained wetlands (DWs), and pastures (PASs) on the variability in CO2, CH4, and N2O emissions from the natural coastal wetlands, riparian wetlands, and peatlands. Our results showed that the natural wetlands were net sinks of atmospheric CO2 and net sources of CH4 and N2O, exhibiting the capacity to mitigate greenhouse effects due to negative comprehensive global warming potentials (GWPs; −0.9 to −8.7 t CO2‐eq ha−1 year−1). Relative to the natural wetlands, all LULCC types (except CWs from coastal wetlands) decreased the net CO2 uptake by 69.7%−456.6%, due to a higher increase in ecosystem respiration relative to slight changes in gross primary production. The CWs and APs significantly increased the CH4 emissions compared to those of the coastal wetlands. All LULCC types associated with the riparian wetlands significantly decreased the CH4 emissions. When the peatlands were converted to the PASs, the CH4 emissions significantly increased. The CLs, as well as DWs from peatlands, significantly increased the N2O emissions in the natural wetlands. As a result, all LULCC types (except PASs from riparian wetlands) led to remarkably higher GWPs by 65.4%−2,948.8%, compared to those of the natural wetlands. The variability in GHG fluxes with LULCC was mainly sensitive to changes in soil water content, water table, salinity, soil nitrogen content, soil pH, and bulk density. This study highlights the significant role of LULCC in increasing comprehensive GHG emissions from global natural wetlands, and our results are useful for improving future models and manipulative experiments.

Integrating climate adaptation and biodiversity conservation in the global ocean

The impacts of climate change and the socioecological challenges they present are ubiquitous and increasingly severe. Practical efforts to operationalize climate-responsive design and management in the global network of marine protected areas (MPAs) are required to ensure long-term effectiveness for safeguarding marine biodiversity and ecosystem services. Here, we review progress in integrating climate change adaptation into MPA design and management and provide eight recommendations to expedite this process. Climate-smart management objectives should become the default for all protected areas, and made into an explicit international policy target. Furthermore, incentives to use more dynamic management tools would increase the climate change responsiveness of the MPA network as a whole. Given ongoing negotiations on international conservation targets, now is the ideal time to proactively reform management of the global seascape for the dynamic climate-biodiversity reality.

Green and grey infrastructures approaches in flood reduction

Purpose: This paper aims to advance the idea of sustainable flood reduction. Flood reduction through the use of the drainage system is considered an unsustainable approach that decreases the use of water. In contrast, the Water Sensitive City is a sustainable concept aimed at increasing the value of water for human needs and reduce flooding. Design/methodology/approach: The current approach of relying on drainage systems is ineffective and must be combined with green infrastructures to reduce flooding. Green infrastructures can increase infiltration rates or facilitate rain harvesting. The study developed four scenarios that combine green and grey infrastructures and used the Soil and Water Assessment Tool (SWAT) model to select the most effective scenario based on the remaining amount of flood volume in every scenario. Findings: Green infrastructures that are related to increased infiltration and rain-harvesting instruments reduced flooding by 22.3 and 27.7 per cent, respectively. Furthermore, a combination of the two types of green infrastructures reduced flooding up to 45.5 per cent. Conversely, applying only grey infrastructures (by increasing drainage capacity) to reduce the flooding to zero is unfeasible, as this requires more than double the current capacity. Therefore, a combination of green and grey infrastructures can significantly reduce flooding in a water sensitive and feasible manner. Originality/value: Applying a combination of green and grey infrastructures is a new and effective approach to reduce flooding in the Kedurus Catchment Area.

A systematic review of the human health and social well-being outcomes of green infrastructure for stormwater and flood management

Background: The increase in frequency and intensity of urban flooding is a global challenge. Flooding directly impacts residents of industrialized cities with aging combined sewer systems, as well as cities with less centralized infrastructure to manage stormwater, fecal sludge, and wastewater. Green infrastructure is growing in popularity as a sustainable strategy to mimic nature-based flood management. Although its technical performance has been extensively studied, little is known about the effects of green stormwater infrastructure on human health and social well-being. Methods: We conducted a multidisciplinary systematic review of peer-reviewed and gray literature on the effects of green infrastructure for stormwater and flood management on individuals’, households’, and communities’ a) physical health; b) mental health; c) economic well-being; and d) flood resilience and social acceptance of green infrastructure. We systematically searched databases such as PubMed, Web of Science, and Scopus; the first 300 results in Google Scholar; and websites of key organizations including the United States Environmental Protection Agency. Study quality and strength of evidence was assessed for included studies, and descriptive data were extracted for a narrative summary. Results: Out of 21,213 initial results, only 18 studies reported health or social well-being outcomes. Seven of these studies used primary data, and none allowed for causal inference. No studies connected green infrastructure for stormwater and flood management to mental or physical health outcomes. Thirteen studies were identified on economic outcomes, largely reporting a positive association between green infrastructure and property values. Five studies assessed changes in perceptions about green infrastructure, but with mixed results. Nearly half of all included studies were from Portland, Oregon. Conclusions: This global systematic review highlights the minimal evidence on human health and social well-being relating to green infrastructure for stormwater and flood management. To enable scale-up of this type of infrastructure to reduce flooding and improve ecological and human well-being, widespread acceptance of green infrastructure will be essential. Policymakers and planners need evidence on the full range of benefits from different contexts to enable financing and implementation of instfrastructure options, especially in highly urbanized, flood-prone settings around the world. Therefore, experts in social science, public health, and program evaluation must be integrated into interdisciplinary green infrastructure research to better relate infrastructure design to tangible human outcomes.

Time equals money? Valuing ecosystem-based adaptation in a developing country context

To guide investments in ecosystem-based adaptation (EbA) in developing countries, numerous stated preference valuation studies have been implemented to assess the value of ecosystem services. These studies increasingly use time payments as an alternative to money. There is limited knowledge, however, about how to convert time to money and how the type of payment affects willingness to pay (WTP). In this study, the results of choice experiments using time and money payments are compared in the context of EbA measures in Vietnam. Six, of which five individual-specific, conversion rates are applied. WTP estimates are found to be higher for time payments. Moreover, the type of payment vehicle as well as the conversion rate has substantial effect on mean WTP and WTP distributions. We discuss implications of these results for the conversion of time to money and the use of resulting WTP estimates in cost benefit analyses in developing countries.

Nurturing ecosystem-based adaptations in South Africa’s Garden Route: a common pool resource governance perspective

Increasing human demands for ecosystem services due to climate change, population growth, poverty, lack of employment, tourism, and concomitant coastal property development threatens adaptive capacity in South Africa’s coastlines. Adaptation strategies frequently propose ecosystem-based adaptation (EBA) as a model for transformative change. However, several studies point to difficulties implementing EBA across the world. The aim of this paper is to assess to what extent social-ecological systems approaches and common pool resource (CPR) governance theories could inform EBA. Data obtained from interviews and surveys with policy makers and residents in South Africa’s Garden Route District were interpreted using the robustness framework (RF) and the design principles (DPs), two common tools for analyzing CPR governance. We found that the Garden Route coast is threatened by negative interactions between hard public and private infrastructures and ecological infrastructures (the cornerstone of EBA) which are driven by weak local government bodies and asymmetrical power relations. By coding the data for elements/interactions within the RF and then identifying and mapping the DPs onto the RF, we also revealed ways to leverage transformative EBA in the Garden Route. Our analyses suggest that the interactions between human-made and ecological infrastructures, as well as power relation, should be at the core of any development debate. Trade-offs should aim for maximum congruence between sustainability and equity in ecosystem services provisioning. This paper provides some considerations for researchers and decision makers to leverage transformative EBA that could potentially apply to areas experiencing similar challenges.

Global priority areas for ecosystem restoration

Extensive ecosystem restoration is increasingly seen as being central to conserving biodiversity1 and stabilizing the climate of the Earth2. Although ambitious national and global targets have been set, global priority areas that account for spatial variation in benefits and costs have yet to be identified. Here we develop and apply a multicriteria optimization approach that identifies priority areas for restoration across all terrestrial biomes, and estimates their benefits and costs. We find that restoring 15% of converted lands in priority areas could avoid 60% of expected extinctions while sequestering 299 gigatonnes of CO2—30% of the total CO2 increase in the atmosphere since the Industrial Revolution. The inclusion of several biomes is key to achieving multiple benefits. Cost effectiveness can increase up to 13-fold when spatial allocation is optimized using our multicriteria approach, which highlights the importance of spatial planning. Our results confirm the vast potential contributions of restoration to addressing global challenges, while underscoring the necessity of pursuing these goals synergistically.

Evaluating wider benefits of natural flood management strategies: An ecosystem-based adaptation perspective

Climate change is projected to alter river flows and the magnitude/frequency characteristics of floods and droughts. Ecosystem-based adaptation highlights the interdependence of human and natural systems, and the potential to buffer the impacts of climate change by maintaining functioning ecosystems that continue to provide multiple societal benefits. Natural flood management (NFM), emphasising the restoration of innate hydrological pathways, provides important regulating services in relation to both runoff rates and water quality and is heralded as a potentially important climate change adaptation strategy. This paper draws together 25 NFM schemes, providing a meta-analysis of hydrological performance along with a wider consideration of their net (dis) benefits. Increasing woodland coverage, whilst positively linked to peak flow reduction (more pronounced for low magnitude events), biodiversity and carbon storage, can adversely impact other provisioning service-especially food production. Similarly, reversing historical land drainage operations appears to have mixed impacts on flood alleviation, carbon sequestration and water quality depending on landscape setting and local catchment characteristics. Wetlands and floodplain restoration strategies typically have fewer disbenefits and provide improvements for regulating and supporting services. It is concluded that future NFM proposals should be framed as ecosystem-based assessments, with trade-offs considered on a case-by-case basis.

Environmental and climate policy integration: Targeted strategies for overcoming barriers to nature-based solutions and climate change adaptation

Nature-based adaptation planning is a challenging endeavor, not least because it requires transdisciplinary approaches to unite different actors’ efforts and capacities. However, empirical knowledge on associated governance processes is scarce and fragmented. Against this background, this paper examines the integration of nature-based approaches for climate change adaptation into municipalities’ daily planning practices and associated governance. A city-to-city learning lab was established to systematically analyze selected urban development projects step-by-step, from the initial idea, to comprehensive and detailed planning, procurement, implementation, maintenance and follow-up. The results show the numerous constraints municipal staff face and how they use targeted strategies to overcome them and tap into existing drivers. We identify five, complementary strategies: i) targeted stakeholder collaboration; ii) strategic citizen involvement; iii) outsourcing; iv) the alteration of internal working structures; and v) concealed science–policy integration. Importantly, these strategies reveal an increasing need for relational approaches that, in turn, require individuals to develop the cognitive/emotional capacity to establish trust, communicate inclusively and promote social learning, while at the same time dealing with an increasingly complex and uncertain working environment. We conclude that tapping into the potential of nature-based solutions for climate adaptation governance requires more financial and human resources, and capacity development to support personal development, systematic mainstreaming and, ultimately, more sustainable development.