Harnessing the potential of nature-based solutions for mitigating and adapting to climate change

Designing an effective incentive scheme for climate change mitigation in energy forests

Energy forests play a crucial role in carbon sequestration and biodiesel production, offering significant potential for mitigating climate change while enhancing energy security. However, current payment schemes are inefficient due to short durations and failure to consider the heterogeneity among private forest owners, leading to suboptimal budget utilisation. This study introduces an innovative "carrot and stick" incentive scheme that integrates subsidies and taxation within a unified framework. By incorporating the social carbon price concept and a principal-agent mechanism into the Land Expectation Value model, the proposed scheme incentivises private forest owners to optimize carbon reductions by accounting for soil quality. Soil quality influences timber yield-contributing to carbon storage in wood biomass-and seed yield, which reduces carbon emissions by substituting diesel with biodiesel. An empirical analysis of Pistacia chinensis forests demonstrates that the proposed scheme can extend optimal rotation ages, especially for forests on low-quality soil. Tailored subsidies that reflect forest heterogeneity further prolong rotation ages, albeit at the cost of government payments in information rents. Meanwhile, taxation ensures alignment between sustainable forest management, biodiesel utilisation, and carbon neutrality objectives. This approach offers actionable insights for policymakers in designing future incentive schemes that promote sustainable forest management and enhance the contribution of forests to climate change mitigation.

Susceptibility to Photosynthesis Suppression From Extreme Storms Is Highly Site-Dependent

Extreme storms are becoming more intense and frequent under climate change. Although these extreme wet events are smaller in extent and duration than drought events, recent evidence suggests the global impact of both extremes is similar. However, the impact of individual extreme storms on photosynthesis-and therefore on vegetation and the carbon cycle-remains difficult to predict, as photosynthesis may be suppressed via waterlogging or increased by the alleviation of moisture stress. Here, we use random forest models to calculate daily photosynthesis anomalies attributable to extreme soil moisture using data from 54 FLUXNET sites across the globe. We hypothesize that photosynthesis' response to a given extreme event is primarily controlled by storm intensity, and to a lesser degree by site vegetation, climate, soil, and topography. However, we find instead that photosynthesis responses are better explained by site characteristics (soil texture, climate, topography, and vegetation density) than by storm intensity, such that the likelihood of waterlogging from a given storm is heavily site-dependent. Although storms that induce waterlogging are roughly as common as those that induce stress alleviation overall, photosynthesis rarely declines at sites not prone to waterlogging. Instead, photosynthesis anomalies at these sites show a much weaker relationship with storm intensity. Increasingly intense storms are therefore unlikely to impact all locations equally. This highlights the potential to use site characteristics to enhance prediction of storm effects on ecosystems and the land carbon sink.

Mitigation justice

Mitigating climate change and social injustice are critical, interwoven challenges. Climate change is driven by grossly unequal contributions to elevated greenhouse gas emissions among individuals, socioeconomic groups, and nations. Yet, its deleterious impacts disproportionately affect poor and less powerful nations, and the poor and the less powerful within each nation. This climate injustice prompts a call for mitigation strategies that buffer the poorest and the most vulnerable against climate change impacts. Unfortunately, all emissions mitigation strategies also reshape social, economic, political, and ecological processes in ways that may create climate change mitigation injustices-i.e., a unique set of injustices not caused by climate change, but by the strategies designed to stem it. Failing to stop climate change is not an answer-this will swamp all adverse impacts of even unjust mitigation in terms of the scope and scale of disastrous consequences. However, mitigation without justice will create uniquely negative consequences for the more vulnerable. The ensuing analysis systematically assesses how climate change mitigation strategies can generate or ameliorate injustices. We first examine how climate science and social justice interact within and among countries. We then ask what there is to learn from the available evidence on how emissions reductions, well-being, and equity have unfolded in a set of countries. Finally, we discuss the intersection between emissions reduction and mitigation justice through actions in important domains including energy, technology, transport, and food systems; nature-based solutions; and policy and governance.

An open-access database of nature-based carbon offset project boundaries

Nature-based climate solutions (NBS) have become an important component of strategies aiming to reduce atmospheric CO2 and mitigate climate change impacts. Carbon offsets have emerged as one of the most widely implemented NBS strategies, however, these projects have also been criticized for exaggerating offsets. Verifying the efficacy of NBS-derived carbon offset is complicated by a lack of readily available geospatial boundary data. Herein, we detail methods and present a database of nature-based offset project boundaries. This database provides the locations of 575 NBS projects distributed across 55 countries. Geospatial boundaries were aggregated using a combination of scraping data from carbon project registries (n = 433, 75.3%) as well as manual georeferencing and digitization (n = 127, 22.1%). Database entries include three varieties of carbon projects: avoided deforestation, afforestation, reforestation and re-vegetation, and improved forest management. An accuracy assessment of the georeferencing and digitizing process indicated a high degree of accuracy (intersection over union score of 0.98 ± 0.015).

Ecosystem resilience response to forest fragmentation in China: Thresholds identification

Ecosystem resilience refers to the ability of ecosystems to maintain stability in structure and function when subjected to disturbances. Global declines in resilience, largely driven by climate variability and water constraints, have attracted significant attention. However, the impact of forest fragmentation, particularly its threshold effects, where a sudden shift in ecosystem structure or function occurs once environmental changes surpass a critical point, remains underexplored. To address this gap, we quantified the spatial and temporal dynamics of forest fragmentation and resilience in China from 1990 to 2022 using long-term land use data and satellite-derived vegetation indices, analyzing the consistency of their temporal trends. Using breakpoint regression, we identified thresholds for the impact of forest fragmentation on resilience and explored their applications in ecological management. The results show that approximately 30 % of forest areas have experienced increased fragmentation. Temporal variations in fragmentation and resilience exhibited an overall negative correlation, modulated by vegetation and underlying moisture conditions. Forest fragmentation created a distinct threshold effect on ecological resilience. Below this threshold, fragmentation does not significantly reduce resilience and may even enhance it. However, once fragmentation exceeds the threshold, resilience decreases significantly. Our findings provide valuable insights into the relationship between landscape spatial patterns and resilience, while the identified thresholds can guide the optimization of landscape management practices.

Design and Application of Mesoporous Catalysts for Liquid-Phase Furfural Hydrogenation

Furfural (FAL), a platform molecule derived from biomass through acid-catalyzed processes, holds significant potential for producing various value-added chemicals. Its unique chemical structure, comprising a furan ring and an aldehyde functional group, enables diverse transformation pathways to yield products such as furfuryl alcohol, furan, tetrahydrofuran, and other industrially relevant compounds. Consequently, optimizing catalytic processes for FAL conversion has garnered substantial attention, particularly in selectivity and efficiency. The liquid-phase hydrogenation of FAL has demonstrated advantages, including enhanced catalyst stability and higher product yields. Among the catalysts investigated, mesoporous materials have emerged as promising candidates because of their high surface area, tunable pore structure, and ability to support highly dispersed active sites. These attributes are critical for maximizing the catalytic performance across various reactions, including FAL hydrogenation. This review provides a comprehensive overview of recent advances in mesoporous catalyst design for FAL hydrogenation, focusing on synthesis strategies, metal dispersion control, and structural optimization to enhance catalytic performance. It explores noble metal-based catalysts, particularly highly dispersed Pd systems, as well as transition-metal-based alternatives such as Co-, Cu-, and Ni-based mesoporous catalysts, highlighting their electronic structure, bimetallic interactions, and active site properties. Additionally, metal-organic frameworks are introduced as both catalysts and precursors for thermally derived materials. Finally, key challenges that require further investigation are discussed, including catalyst stability, deactivation mechanisms, strategies to reduce reliance on external hydrogen sources, and the impact of solvent effects on product selectivity. By integrating these insights, this review provides a comprehensive perspective on the development of efficient and sustainable catalytic systems for biomass valorization.

A Nature-based Solutions Framework for Embedding Climate Change Mitigation and Adaptation into Urban Land Use Plans through Strategic Environmental Assessment (SEA)

Climate change impacts comprise a particular challenge for authorities when reconciling the implications of land use planning decisions. Whilst Strategic Environmental Assessment (SEA) is typically applied to the development of urban land use plans, the selection of mitigation and adaptation strategies for climate change impacts can have knock-on effects on nature. However, Nature-based Solutions (NbSs) could provide an innovative means of addressing climate change mitigation and adaptation without these knock-on effects. The main aim of this research is therefore to propose a conceptual framework for embedding NbSs into the main stages of the SEA process to potentially enhance climate change mitigation and adaptation in urban land use planning. This is achieved through a systematic literature review of academic and grey literature sources, with subsequent content analysis. This study demonstrates the value of matching these manifold NbS approaches to climate change impacts potentially addressed in SEA process stages and suggests how this might be achieved in practice focusing on urban land use plans.

Variable impacts of land-based climate mitigation on habitat area for vertebrate diversity

Pathways to achieving net zero carbon emissions commonly involve deploying reforestation, afforestation, and bioenergy crops across millions of hectares of land. It is often assumed that by helping to mitigate climate change, these strategies indirectly benefit biodiversity. Here, we modeled the climate and habitat requirements of 14,234 vertebrate species and show that the impact of these strategies on species' habitat area tends not to arise through climate mitigation, but rather through habitat conversion. Across locations, reforestation tends to provide species more habitat through both land-cover change and climate mitigation, whereas habitat loss from afforestation and bioenergy cropping typically outweighs the climate mitigation benefits. This work shows how and where land-based mitigation strategies can be deployed without inadvertently reducing the area of habitat for global biodiversity.

The Anthropocene and the biodiversity crisis: an eco-evolutionary perspective

A major facet of the Anthropocene is global change, such as climate change, caused by human activities, which drastically affect biodiversity with all-scale declines and homogenization of biotas. This crisis does not only affect the ecological dynamics of biodiversity, but also its evolutionary dynamics, including genetic diversity, an aspect that is generally neglected. My tenet is therefore to consider biodiversity dynamics from an eco-evolutionary perspective, i.e. explicitly accounting for the possibility of rapid evolution and its feedback on ecological processes and the environment. I represent the impact of the various avatars of global change in a temporal perspective, from pre-industrial time to the near future, allowing to visualize their dynamics and to set desired values that should not be trespassed for a given time (e.g., +2 °C for 50 years from now). After presenting the impact of various stressors (e.g., climate change) on biodiversity, this representation is used to heuristically show the relevance of an eco-evolutionary perspective: (i) to analyze how biodiversity will respond to the stressors, for example by seeking out more suitable conditions or adapting to new conditions; (ii) to serve in predictive exercises to envision future dynamics (decades to centuries) under stressor impact; (iii) to propose nature-based solutions to the crisis. Significant obstacles stand in the way of the development of such an approach, in particular the general lack of interest in intraspecific diversity, and perhaps more generally a lack of understanding that, we, humans, are only a modest part of biodiversity.

Assessing carbon stock change for effective Nature-based Solutions implementation allocation: A framework

Mapping and assessing the carbon stock change (CSC) in urban areas can support the allocation of Nature-based Solutions (NbS) to mitigate climate change and advance urban sustainability. However, an effective framework concerning historical CSC and future simulation to support the allocation of NbS implementation is lacking. To fill this gap, we proposed a framework and applied it in the Zhejiang coastal region based on the assessment of historical (from 1990 to 2020) and predicted future (2030) CSC and local context analysis of urban and ecosystem challenges. Over the past three decades, the Zhejiang coastal region has experienced a considerable C stock loss of 20.34 Tg, predominantly owing to fast urbanization. The severest C stock reduction occurred from 2000 to 2010, with a slowdown in the following decade. Even so, more effective spatial management policies are urgent to mitigate further C stock depletion. Our framework identified 50.51% of the study area as the allocation area for NbS implementations where current and future C sequestration demand existed. Within the allocation area, six NbS types identified from literature were allocated or co-allocated, leading to eight tailored NbS implementations to tackle specific urban and ecosystem challenges of each location. The most widely allocated NbS implementations were "NbS1 × NbS2 × NbS3" and "NbS2 × NbS4", covering 42.86% and 34.69% of the allocation area. NbS2 covered nearly the entire allocation area (98.80%), with its primary role of habitat preservation and to control urban expansion. The proposed framework can be adapted to support various planning decisions regarding the prioritization and spatial allocation of NbS.

How to make land use policy decisions: Integrating science and economics to deliver connected climate, biodiversity, and food objectives

Land use change is crucial to addressing the existential threats of climate change and biodiversity loss while enhancing food security [M. Zurek et al., Science 376, 1416-1421 (2022)]. The interconnected and spatially varying nature of the impacts of land use change means that these challenges must be addressed simultaneously [H.-O. Pörtner et al., Science 380, eabl4881 (2023)]. However, governments commonly focus on single issues, incentivizing land use change via "Flat-Rate" subsidies offering constant per hectare payments, uptake of which is determined by the economic circumstances of landowners rather than the integrated environmental outcomes that will be delivered [G. Q. Bull et al., Forest Policy Econ. 9, 13-31 (2006)]. Here, we compare Flat-Rate subsidies to two alternatives: "Land Use Scenario" allocation of subsidies through consultation across stakeholders and interested parties; and a "Natural Capital" approach which targets subsidies according to expected ecosystem service response. This comparison is achieved by developing a comprehensive decision support system, integrating new and existing natural, physical, and economic science models to quantify environmental, agricultural, and economic outcomes. Applying this system to the United Kingdom's net zero commitment to increase carbon storage via afforestation, we show that the three approaches result in significantly different outcomes in terms of where planting occurs, their environmental consequences, and economic costs and benefits. The Flat-Rate approach actually increases net carbon emissions while Land Use Scenario allocation yields poor economic outcomes. The Natural Capital targeted approach outperforms both alternatives, providing the highest possible social values while satisfying net zero commitments.

What is limiting how we imagine climate change adaptation?

Imaginaries of adaptation are currently dominated by technocratic, homogenous, top-down approaches that hinder sustainable, just, and effective adaptation worldwide. We have identified three practices that contribute to this problem: (1) an assumption of universality in adaptation; (2) a neglect of pluralistic knowledge systems and values; and (3) an oversimplification of adaptation processes. These three practices have been found to lead to reproductions of vulnerabilities, unsustainable outcomes, or ephemeral changes. New ways of conceptualising and doing adaptation are necessary to expand imaginaries and visions around what adaptation can and cannot be. Through two examples (everyday adaptations and nature-based solutions), our review indicates that expanding or adopting alternative imaginaries of adaptation can help localise adaptation practice, particularly by acknowledging the need for multiple forms of knowledge and the iterative nature of adaptation governance processes.

Global suitability and spatial overlap of land-based climate mitigation strategies

Land-based mitigation strategies (LBMS) are critical to reducing climate change and will require large areas for their implementation. Yet few studies have considered how and where LBMS either compete for land or could be deployed jointly across the Earth's surface. To assess the opportunity costs of scaling up LBMS, we derived high-resolution estimates of the land suitable for 19 different LBMS, including ecosystem maintenance, ecosystem restoration, carbon-smart agricultural and forestry management, and converting land to novel states. Each 1 km resolution map was derived using the Earth's current geographic and biophysical features without socioeconomic constraints. By overlaying these maps, we estimated 8.56 billion hectares theoretically suitable for LBMS across the Earth. This includes 5.20 Bha where only one of the studied strategies is suitable, typically the strategy that involves maintaining the current ecosystem and the carbon it stores. The other 3.36 Bha is suitable for more than one LBMS, framing the choices society has among which LBMS to implement. The majority of these regions of overlapping LBMS include strategies that conflict with one another, such as the conflict between better management of existing land cover types and restoration-based strategies such as reforestation. At the same time, we identified several agricultural management LBMS that were geographically compatible over large areas, including for example, enhanced chemical weathering and improved plantation rotations. Our analysis presents local stakeholders, communities, and governments with the range of LBMS options, and the opportunity costs associated with scaling up any given LBMS to reduce global climate change.

Nature-based solutions for improving food security: A systematic global review

Nature-based solutions (NBS) have been promoted as a holistic way to solve a variety of societal issues while benefiting biodiversity at the same time. To date, applications of NBS approaches that help ensure food security have yet been systematically reviewed. In this paper, we critically review the specific NBS for food security, highlighting their limitations, to provide recommendations that promote their applications for improving global food security. We accessed and evaluated publications on four different scholastic databases, and our systematic review of relevant materials indicated that many NBS approaches can be applied to enhance food security dimensions individually or together. However, there is a strong bias towards food availability, and not enough research has been done to link NBS with improvements in food access and utilization. Over 80 % of the reviewed papers were of short-term studies or without specific timeframes, and 25 % offered no information on the economic effectiveness of NBS. Environmental benefits of NBS were explicitly described in about 60 % of these papers, and biodiversity enhancement was measured in only about 10 %. We, therefore, recommend future applications of NBS to safeguard food security be shifted to food access and utilization with careful consultation with local communities to address their specific context, using indicators that are easily measured and managed. Systematic monitoring regimes and robust and diversified financial support systems are also equally important in efforts to successfully implement NBS. Moreover, environmental and societal benefits, especially water productivity and biodiversity, must be incorporated into the planning and design of NBS.

Conservation opportunities through improved management of recently established protected areas in Southeast Asia

Protected areas (PAs) play a crucial role in biodiversity conservation and climate change mitigation.1,2 However, ineffective management can lead to biodiversity loss and carbon emissions from deforestation.3,4,5,6 To address this issue and explore viable solutions, we assessed the impact of PA establishment on avoided deforestation in 80 Southeast Asian PAs using the synthetic control approach.7,8 Our results show that 36 PAs successfully prevented 78,910 ha of deforestation. However, the remaining 44 PAs lost 72,497 ha of forest, impacting the habitat of 226 threatened bird and mammal species. Effective management of these reserves could have potentially avoided up to 2.07 MtCO2e yr-1 in carbon emissions. We estimate that at least $17 million USD per year in additional funding is required to better manage these 44 ineffective PAs and reduce future emissions. Furthermore, we demonstrate that carbon markets have the potential to generate these funds by reducing carbon emissions from deforestation within protected areas. Our findings emphasize that improving PA management is an essential nature-based solution for conserving biodiversity and mitigating climate change.

Cultivating climate resilience in California agriculture: Adaptations to an increasingly volatile water future

California agriculture will undergo significant transformations over the next few decades in response to climate extremes, environmental regulation and policy encouraging environmental justice, and economic pressures that have long driven agricultural changes. With several local climates suited to a variety of crops, periodically abundant nearby precipitation, and public investments that facilitated abundant low-priced irrigation water, California hosts one of the most diverse and productive agroecosystems in the world. California farms supply nearly half of the high-nutrient fruit, tree nut, and vegetable production in the United States. Climate change impacts on productivity and profitability of California agriculture are increasing and forebode problems for standard agricultural practices, especially water use norms. We highlight many challenges California agriculture confronts under climate change through the direct and indirect impacts on the biophysical conditions and ecosystem services that drive adaptations in farm practices and water accessibility and availability. In the face of clear conflicts among competing interests, we consider ongoing and potential sustainable and equitable solutions, with particular attention to how technology and policy can facilitate progress.

On the cost-effectiveness of Nature-based Solutions for reducing disaster risk

The potential of ecosystem-based interventions, also known as Nature-based Solutions (NbS), for Disaster Risk Reduction (DRR) and Climate Change Adaptation (CCA) is now recognized by major national policies and international framework agreements. However, there is limited scientific evidence about their economic viability and equity impacts. We examined English-language peer-reviewed studies, published between 2000 and 2021, which undertook economic evaluations of NbS for DRR and CCA. Based on our results, 71 % of studies indicated that NbS have consistently proven to be a cost-effective approach to mitigating hazards and 24 % of studies found NbS cost-effective under certain conditions. The ecosystem-based interventions most frequently found effective in mitigating hazards are associated with mangroves (80 %), forests (77 %), and coastal ecosystems (73 %). Studies comparing the cost-effectiveness of NbS and engineering-based solutions for mitigating certain hazards showed that NbS are no less effective than engineering-based solutions. Among these studies, 65 % found that NbS are always more effective in attenuating hazards compared to engineering-based solutions and 26 % found that NbS are partially more effective. Our findings illustrate a range of factors, including the geographic locations of the NbS analyzed, their contribution to the restoration and increase of biodiversity, their property rights structure, their source of financing, and the economic methodologies employed to assess cost-effectiveness and distributional effects. The geographic location of the NbS observations included in this analysis was examined considering global projected temperature and precipitation changes.

Reducing heat exposure from personal cooling strategies to green city construction in China's tropical city

With rapid industrialization and urbanization, the risk of summer heat exposure for urban dwellers has increased. The use of air conditioners (ACs) has become the most common personal cooling strategy, but further increasing fossil fuel consumption. As sustainable and affordable cooling strategies, urban parks can reduce heat exposure and substitute a part of air conditioners use. This study evaluates the heat exposure reduction from personal cooling to urban parks based on satellite images, questionnaire surveys, and network analysis in Liuzhou, one tropical city in China. We found that residents with lower income had a higher risk of heat exposure. Among the respondents, 85 % of residents chose to use ACs to alleviate high temperatures in summer, and 81.8 % among them were willing to access park cooling area (PCA) to cool off instead of using ACs. About one third parks could serve as potential alternatives (with temperatures <28 °C) to air conditioning, reducing carbon emissions by 175.93 tons per day during the hot summer and offsetting 2.5 % of urban fossil fuel carbon emissions. The design of parks should give more consideration to elder people and provide a good cooling platform for various social income groups. Future planning should also focus on accessibility to enable residents to fully utilize the parks. Building parks within 34.10 ha would provide a more efficient use of land. This research guides sustainable, high-quality growth in industrial cities and might contribute to promotion of low-carbon cities and social equity.

Harnessing the runoff reduction potential of urban bioswales as an adaptation response to climate change

Nature-based solutions (NbS), including China's Sponge City Program (SCP), can address the challenges urban communities face due to surface runoff and flooding. The current capacity of SCP facilities in urban environments falls short of meeting the demands placed on communities by climate change. Bioswales are a form of SCP facility that plays an important role in reducing surface runoff by promoting infiltration. This study assesses the potential of SCP facilities to reduce runoff in urban communities under climate change using the storm water management model. The study site in Ningbo, China, was used to evaluate the potential role of bioswales in reducing runoff risks from climate change. We found that bioswales were most effective in scenarios when rainfall peaks occurred early and were less effective in right-skewed rainfall events. The overall performance of SCP facilities was similar across all climate scenarios. To maintain the current protection level of SCP facilities, bioswales would need to cover at least 4% of the catchment area. These findings from Ningbo provide a useful method for assessing NbS in other regions and indicative values for the increase in the bioswale coverage needed to adapt to climate change.

Carbon storage through China's planted forest expansion

China's extensive planted forests play a crucial role in carbon storage, vital for climate change mitigation. However, the complex spatiotemporal dynamics of China's planted forest area and its carbon storage remain uncaptured. Here we reveal such changes in China's planted forests from 1990 to 2020 using satellite and field data. Results show a doubling of planted forest area, a trend that intensified post-2000. These changes lead to China's planted forest carbon storage increasing from 675.6 ± 12.5 Tg C in 1990 to 1,873.1 ± 16.2 Tg C in 2020, with an average rate of ~ 40 Tg C yr-1. The area expansion of planted forests contributed ~ 53% (637.2 ± 5.4 Tg C) of the total above increased carbon storage in planted forests compared with planted forest growth. This proactive policy-driven expansion of planted forests has catalyzed a swift increase in carbon storage, aligning with China's Carbon Neutrality Target for 2060.

Urbanization-driven forest soil greenhouse gas emissions: Insights from the role of soil bacteria in carbon and nitrogen cycling using a metagenomic approach

Increasing population densities and urban sprawl have induced greenhouse gas (GHG) emissions from the soil, and the soil microbiota of urban forests play a critical role in the production and consumption of GHGs, supporting green development. However, the function and potential mechanism of soil bacteria in GHG emissions from forests during urbanization processes need to be better understood. Here, we measured the fluxes of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) in Cinnamomum camphora forest soils along an urbanization gradient. 16S amplicon and metagenomic sequencing approaches were employed to examine the structure and potential functions of the soil bacterial community involved in carbon (C) and nitrogen (N) cycling. In this study, the CH4 and CO2 emissions from urban forest soils (sites U and G) were significantly greater than those from suburban soils (sites S and M). The N2O emissions in the urban center (site U) were 24.0 % (G), 13.8 % (S), and 13.5 % (M) greater than those at the other three sites. These results were related to the increasing bacterial alpha diversity, interactions, and C and N cycling gene abundances (especially those involved in denitrification) in urban forest soils. Additionally, the soil pH and metal contents (K, Ca, Mg) affected key bacterial populations (such as Methylomirabilota, Acidobacteriota, and Proteobacteria) and indicators (napA, nosZ, nrfA, nifH) involved in reducing N2O emissions. The soil heavy metal contents (Fe, Cr, Pb) were the main contributors to CH4 emissions, possibly by affecting methanogens (Desulfobacterota) and methanotrophic bacteria (Proteobacteria, Actinobacteriota, and Patescibacteria). Our study provides new insights into the benefits of conservation-minded urban planning and close-to-nature urban forest management and construction, which are conducive to mitigating GHG emissions and supporting urban sustainable development by mediating the core bacterial population.

Assessing the potential of nature-based solutions for restoring soil ecosystem services in croplands

Nature-based solutions (NBSs) are emerging as an innovative approach to maintain or restore the declining soil ecosystem services. The extent to which the implementation of NBSs in croplands improves soil ecosystem services deserves, however, further discussion. This review discusses the potential of prairie strips, grass buffers, agroforestry, cover crops, and organic systems as NBSs in croplands for reducing greenhouse gas emissions, sequestering soil C, improving water and air quality, improving biodiversity, and adapting to climatic fluctuations. It also highlights challenges (if any) with the adoption of the NBSs. Literature indicates incorporation of prairie strips, grass buffers, agroforestry, cover crop, and organic systems into croplands can accumulate soil C, reduce soil erosion and nutrient losses, improve soil biodiversity, and contribute to climate change adaptation in this order: Grass buffers = Prairie strips = Agroforestry > Cover crops > Organic systems. This suggests NBSs based on perennial vegetation offer more promise than those based on annual crops. Buffers and agroforestry (1.0 Mg C ha-1 yr-1) accumulate more soil C than cover crops and organic systems (<0.5 Mg C ha-1 yr-1), but soil C data under prairie strips are still scant. The practices discussed can be effective at balancing environmental quality and crop production. Some challenges and trade-offs of the practices discussed include variable or no soil impacts in the short term (<10 yr), variable and shallow soil C accumulation, no increase in crop yields, and limited management guidelines and policy support. Overall, NBSs can improve soil ecosystem services in croplands and contribute to climate change adaptation.

Global production patterns: Understanding the relationship between greenhouse gas emissions, agriculture greening and climate variability

Climate change due to increased greenhouse gas emissions (GHG) in the atmosphere has been consistently observed since the mid-20th century. The profound influence of global climate change on greenhouse gas (GHG) emissions, encompassing carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), has established a vital feedback loop that contributes to further climate change. This intricate relationship necessitates a comprehensive understanding of the underlying feedback mechanisms. By examining the interactions between global climate change, soil, and GHG emissions, we can elucidate the complexities of CO2, CH4, and N2O dynamics and their implications. In this study, we evaluate the global climate change relationship with GHG globally in 246 countries. We find a robust positive association between climate and GHG emissions. By 2100, GHG emissions will increase in all G7 countries and China while decreasing in the United Kingdom based on current economic growth policies, resulting in a net global increase, suggesting that climate-driven increase in GHG and climate variations impact crop production loss due to soil impacts and not provide climate adaptation. The study highlights the diverse strategies employed by G7 countries in reducing GHG emissions, with France leveraging nuclear power, Germany focusing on renewables, and Italy targeting its industrial and transportation sectors. The UK and Japan are making significant progress in emission reduction through renewable energy, while the US and Canada face challenges due to their industrial activities and reliance on fossil fuels.

Surface engineering for stable electrocatalysis

In recent decades, significant progress has been achieved in rational developments of electrocatalysts through constructing novel atomistic structures and modulating catalytic surface topography, realizing substantial enhancement in electrocatalytic activities. Numerous advanced catalysts were developed for electrochemical energy conversion, exhibiting low overpotential, high intrinsic activity, and selectivity. Yet, maintaining the high catalytic performance under working conditions with high polarization and vigorous microkinetics that induce intensive degradation of surface nanostructures presents a significant challenge for commercial applications. Recently, advanced operando and computational techniques have provided comprehensive mechanistic insights into the degradation of surficial functional structures. Additionally, various innovative strategies have been devised and proven effective in sustaining electrocatalytic activity under harsh operating conditions. This review aims to discuss the most recent understanding of the degradation microkinetics of catalysts across an entire range of anodic to cathodic polarizations, encompassing processes such as oxygen evolution and reduction, hydrogen reduction, and carbon dioxide reduction. Subsequently, innovative strategies adopted to stabilize the materials' structure and activity are highlighted with an in-depth discussion of the underlying rationale. Finally, we present conclusions and perspectives regarding future research and development. By identifying the research gaps, this review aims to inspire further exploration of surface degradation mechanisms and rational design of durable electrocatalysts, ultimately contributing to the large-scale utilization of electroconversion technologies.

Economic assessment of nature-based solutions to reduce flood risk and enhance co-benefits

Flooding is expected to increase due to climate change, urbanisation, and land use change. To address this issue, Nature-Based Solutions (NBSs) are often adopted as innovative and sustainable flood risk management methods. Besides the flood risk reduction benefits, NBSs offer co-benefits for the environment and society. However, these co-benefits are rarely considered in flood risk management due to the inherent complexities of incorporating them into economic assessments. This research addresses this gap by developing a comprehensive methodology that integrates the monetary analysis of co-benefits with flood risk reduction in economic assessments. In doing so, it aspires to provide a more holistic view of the impact of NBS in flood risk management. The assessment employs a framework based on life-cycle cost-benefit analysis, offering a systematic and transparent assessment of both costs and benefits over time supported by key indicators like net present value and benefit cost ratio. The methodology has been applied to the Tamnava basin in Serbia, where significant flooding occurred in 2014 and 2020. The methodology offers valuable insights for practitioners, researchers, and planners seeking to assess the co-benefits of NBS and integrate them into economic assessments. The results show that when considering flood risk reduction alone, all considered measures have higher costs than the benefits derived from avoiding flood damage. However, when incorporating co-benefits, several NBS have a net positive economic impact, including afforestation/reforestation and retention ponds with cost-benefit ratios of 3.5 and 5.6 respectively. This suggests that incorporating co-benefits into economic assessments can significantly increase the overall economic efficiency and viability of NBS.

Nature-based solutions are critical for putting Brazil on track towards net-zero emissions by 2050

Most of the world's nations (around 130) have committed to reaching net-zero carbon dioxide or greenhouse gas (GHG) emissions by 2050, yet robust policies rarely underpin these ambitions. To investigate whether existing and expected national policies will allow Brazil to meet its net-zero GHG emissions pledge by 2050, we applied a detailed regional integrated assessment modelling approach. This included quantifying the role of nature-based solutions, such as the protection and restoration of ecosystems, and engineered solutions, such as bioenergy with carbon capture and storage. Our results highlight ecosystem protection as the most critical cost-effective climate mitigation measure for Brazil, whereas relying heavily on costly and not-mature-yet engineered solutions will jeopardise Brazil's chances of achieving its net-zero pledge by mid-century. We show that the full implementation of Brazil's Forest Code (FC), a key policy for emission reduction in Brazil, would be enough for the country to achieve its short-term climate targets up to 2030. However, it would reduce the gap to net-zero GHG emissions by 38% by 2050. The FC, combined with zero legal deforestation and additional large-scale ecosystem restoration, would reduce this gap by 62% by mid-century, keeping Brazil on a clear path towards net-zero GHG emissions by around 2040. While some level of deployment of negative emissions technologies will be needed for Brazil to achieve and sustain its net-zero pledge, we show that the more mitigation measures from the land-use sector, the less costly engineered solutions from the energy sector will be required. Our analysis underlines the urgent need for Brazil to go beyond existing policies to help fight climate emergency, to align its short- and long-term climate targets, and to build climate resilience while curbing biodiversity loss.

Valuing the functionality of tropical ecosystems beyond carbon

Land-based carbon sequestration projects, such as tree planting, are a prominent strategy to offset carbon emissions. However, we risk reducing natural ecosystems to one metric - carbon. Emphasis on restoring ecosystems to balance ecosystem services, biodiversity conservation, and carbon sequestration is a more appropriate strategy to protect their functioning.

Nature-based solutions can help reduce the impact of natural hazards: A global analysis of NBS case studies

The knowledge derived from successful case studies can act as a driver for the implementation and upscaling of nature-based solutions (NBS). This work reviewed 547 case studies to gain an overview of NBS practices and their role in reducing the adverse impact of natural hazards and climate change. The majority (60 %) of case studies are situated in Europe compared with the rest of the world where they are poorly represented. Of 547 case studies, 33 % were green solutions followed by hybrid (31 %), mixed (27 %), and blue (10 %) approaches. Approximately half (48 %) of these NBS interventions were implemented in urban (24 %), and river and lake (24 %) ecosystems. Regarding the scale of intervention, 92 % of the case studies were operationalised at local (50 %) and watershed (46 %) scales while very few (4 %) were implemented at the landscape scale. The results also showed that 63 % of NBS have been used to deal with natural hazards, climate change, and loss of biodiversity, while the remaining 37 % address socio-economic challenges (e.g., economic development, social justice, inequality, and cohesion). Around 88 % of NBS implementations were supported by policies at the national level and the rest 12 % at local and regional levels. Most of the analysed cases contributed to Sustainable Development Goals 15, 13, and 6, and biodiversity strategic goals B and D. Case studies also highlighted the co-benefits of NBS: 64 % of them were environmental co-benefits (e.g., improving biodiversity, air and water qualities, and carbon storage) while 36 % were social (27 %) and economic (9 %) co-benefits. This synthesis of case studies helps to bridge the knowledge gap between scientists, policymakers, and practitioners, which can allow adopting and upscaling of NBS for disaster risk reduction and climate change adaptation and enhance their preference in decision-making processes.

Scale dependence of urban green space cooling efficiency: A case study in Beijing metropolitan area

Urban Green Space (UGS), providing environmental, social and economic benefits simultaneously, has been regarded as a cost-effective Nature-based Solution (NbS) to combat the effects of urban heat island (UHI). Under the dual pressure of increasing demand for limited land resources and mitigating UHI, how to scientifically and effectively use the limited space to obtain the maximum cooling efficiency (scaling of cooling intensity and UGS size) is an important component of strategic urban green planning. However, the scale dependence of UGS cooling effect has not yet been sufficiently quantified, particularly with respect to involving small and medium size UGS. Here, we explored the size-dependent UGS cooling efficiency in Beijing using 10,003 UGS patches extracted from high-resolution remote sensing images. We found that 5922 UGS (59.20 %) exhibited a "cooling island effect", the cooling service of UGS could reduce land surface temperature by 0.06 ± 0.05 °C to 3.81 ± 1.01 °C, and the cooling intensity enhanced nonlinearly with increasing size and closely related to the complexity of UGS shape and vegetation quality. We further showed that the cooling efficiency of small, medium and large UGS was -0.004 ± 0.03 (n = 2201), 0.79 ± 0.01 (n = 3570), 0.19 ± 0.03 (n = 151), respectively, suggesting that strategic urban greening to combat urban heat should target on increasing medium-sized UGS and managing the layout of green space. These findings emphasize the significance of considering and further exploring the scale dependence of UGS cooling effect in mitigating urban heat.

Nature-based biopsychosocial resilience: An integrative theoretical framework for research on nature and health

Nature-based solutions including urban forests and wetlands can help communities cope better with climate change and other environmental stressors by enhancing social-ecological resilience. Natural ecosystems, settings, elements and affordances can also help individuals become more personally resilient to a variety of stressors, although the mechanisms underpinning individual-level nature-based resilience, and their relations to social-ecological resilience, are not well articulated. We propose 'nature-based biopsychosocial resilience theory' (NBRT) to address these gaps. Our framework begins by suggesting that individual-level resilience can refer to both: a) a person's set of adaptive resources; and b) the processes by which these resources are deployed. Drawing on existing nature-health perspectives, we argue that nature contact can support individuals build and maintain biological, psychological, and social (i.e. biopsychosocial) resilience-related resources. Together with nature-based social-ecological resilience, these biopsychosocial resilience resources can: i) reduce the risk of various stressors (preventive resilience); ii) enhance adaptive reactions to stressful circumstances (response resilience), and/or iii) facilitate more rapid and/or complete recovery from stress (recovery resilience). Reference to these three resilience processes supports integration across more familiar pathways involving harm reduction, capacity building, and restoration. Evidence in support of the theory, potential interventions to promote nature-based biopsychosocial resilience, and issues that require further consideration are discussed.

Soundscapes and deep learning enable tracking biodiversity recovery in tropical forests

Tropical forest recovery is fundamental to addressing the intertwined climate and biodiversity loss crises. While regenerating trees sequester carbon relatively quickly, the pace of biodiversity recovery remains contentious. Here, we use bioacoustics and metabarcoding to measure forest recovery post-agriculture in a global biodiversity hotspot in Ecuador. We show that the community composition, and not species richness, of vocalizing vertebrates identified by experts reflects the restoration gradient. Two automated measures - an acoustic index model and a bird community composition derived from an independently developed Convolutional Neural Network - correlated well with restoration (adj-R² = 0.62 and 0.69, respectively). Importantly, both measures reflected composition of non-vocalizing nocturnal insects identified via metabarcoding. We show that such automated monitoring tools, based on new technologies, can effectively monitor the success of forest recovery, using robust and reproducible data.

Accounting for the climate benefit of temporary carbon storage in nature

Nature-based climate solutions can contribute to climate mitigation, but the vulnerability of land carbon to disturbances means that efforts to slow or reverse land carbon loss could result in only temporary storage. The challenge of accounting for temporary storage is a key barrier to the implementation of nature-based climate mitigation strategies. Here we offer a solution to this challenge using tonne-year accounting, which integrates the amount of carbon over the time that it remains in storage. We show that tonne-years of carbon storage are proportional to degree-years of avoided warming, and that a physically based tonne-year accounting metric could effectively quantify and track the climate benefit of temporary carbon storage. If the world can sustain an increasing number of tonne-years alongside rapid fossil fuel CO2 emissions reductions, then the resulting carbon storage (even if only temporary) would have considerable and lasting climate value by lowering the global temperature peak.

Cost-effective restoration for carbon sequestration across Brazil's biomes

Tropical ecosystems are central to the global focus on halting and reversing habitat destruction as a means of mitigating carbon emissions. Brazil has been highlighted as a vital part of global climate agreements because, whilst ongoing land-use change causes it to be the world's fifth biggest greenhouse gas emitting country, it also has one of the greatest potentials to implement ecosystem restoration. Global carbon markets provide the opportunity of a financially viable way to implement restoration projects at scale. However, except for rainforests, the restoration potential of many major tropical biomes is not widely recognised, with the result that carbon sequestration potential may be squandered. We synthesize data on land availability, land degradation status, restoration costs, area of native vegetation remaining, carbon storage potential and carbon market prices for 5475 municipalities across Brazil's major biomes, including the savannas and tropical dry forests. Using a modelling analysis, we determine how fast restoration could be implemented across these biomes within existing carbon markets. We argue that even with a sole focus on carbon, we must restore other tropical biomes, as well as rainforests, to effectively increase benefits. The inclusion of dry forests and savannas doubles the area which could be restored in a financially viable manner, increasing the potential CO₂e sequestered >40 % above that offered by rainforests alone. Importantly, we show that in the short-term avoiding emissions through conservation will be necessary for Brazil to achieve it's 2030 climate goal, because it can sequester 1.5 to 4.3 Pg of CO₂e by 2030, relative to 0.127 Pg CO₂e from restoration. However, in the longer term, restoration across all biomes in Brazil could draw down between 3.9 and 9.8 Pg of CO₂e from the atmosphere by 2050 and 2080.

Broadening the focus of forest conservation beyond carbon

Two concurrent trends are contributing towards a much broader view of forest conservation. First, the appreciation of the role of forests as a nature-based climate solution has grown rapidly, particularly among governments and the private sector. Second, the spatiotemporal resolution of forest mapping and the ease of tracking forest changes have dramatically improved. As a result, who does and who pays for forest conservation is changing: sectors and people previously considered separate from forest conservation now play an important role and need to be held accountable and motivated or forced to conserve forests. This change requires, and has stimulated, a broader range of forest conservation solutions. The need to assess the outcomes of conservation interventions has motivated the development and application of sophisticated econometric analyses, enabled by high resolution satellite data. At the same time, the focus on climate, together with the nature of available data and evaluation methods, has worked against a more comprehensive view of forest conservation. Instead, it has encouraged a focus on trees as carbon stores, often leaving out other important goals of forest conservation, such as biodiversity and human wellbeing. Even though both are intrinsically connected to climate outcomes, these areas have not kept pace with the scale and diversification of forest conservation. Finding synergies between these 'co-benefits', which play out on a local scale, with the carbon objective, related to the global amount of forests, is a major challenge and area for future advances in forest conservation.

What evidence exists on the performance of nature-based solutions interventions for coastal protection in biogenic, shallow ecosystems? A systematic map protocol

BACKGROUND

Anthropogenic pressures and climate change threaten the capacity of ecosystems to deliver a variety of services, including protecting coastal communities from hazards like flooding and erosion. Human interventions aim to buffer against or overcome these threats by providing physical protection for existing coastal infrastructure and communities, along with added ecological, social, or economic co-benefits. These interventions are a type of nature-based solution (NBS), broadly defined as actions working with nature to address societal challenges while also providing benefits for human well-being, biodiversity, and resilience. Despite the increasing popularity of NBS for coastal protection, sometimes in lieu of traditional hardened shorelines (e.g., oyster reefs instead of bulkheads), gaps remain in our understanding of whether common NBS interventions for coastal protection perform as intended. To help fill these knowledge gaps, we aim to identify, collate, and map the evidence base surrounding the performance of active NBS interventions related to coastal protection across a suite of ecological, physical, social, and economic outcomes in salt marsh, seagrass, kelp, mangrove, shellfish reef, and coral reef systems. The resulting evidence base will highlight the current knowledge on NBS performance and inform future uses of NBS meant for coastal protection.

METHODS

Searches for primary literature on performance of NBS for coastal protection in shallow, biogenic ecosystems will be conducted using a predefined list of indexing platforms, bibliographic databases, open discovery citation indexes, and organizational databases and websites, as well as an online search engine and novel literature discovery tool. All searches will be conducted in English and will be restricted to literature published from 1980 to present. Resulting literature will be screened against set inclusion criteria (i.e., population, intervention, outcome, study type) at the level of title and abstract followed by full text. Screening will be facilitated by a web-based active learning tool that incorporates user feedback via machine learning to prioritize articles for review. Metadata will be extracted from articles that meet inclusion criteria and summarized in a narrative report detailing the distribution and abundance of evidence surrounding NBS performance, including evidence clusters, evidence gaps, and the precision and sensitivity of the search strategy.

Networking the forest infrastructure towards near real-time monitoring - A white paper

Forests account for nearly 90 % of the world's terrestrial biomass in the form of carbon and they support 80 % of the global biodiversity. To understand the underlying forest dynamics, we need a long-term but also relatively high-frequency, networked monitoring system, as traditionally used in meteorology or hydrology. While there are numerous existing forest monitoring sites, particularly in temperate regions, the resulting data streams are rarely connected and do not provide information promptly, which hampers real-time assessments of forest responses to extreme climate events. The technology to build a better global forest monitoring network now exists. This white paper addresses the key structural components needed to achieve a novel meta-network. We propose to complement - rather than replace or unify - the existing heterogeneous infrastructure with standardized, quality-assured linking methods and interacting data processing centers to create an integrated forest monitoring network. These automated (research topic-dependent) linking methods in atmosphere, biosphere, and pedosphere play a key role in scaling site-specific results and processing them in a timely manner. To ensure broad participation from existing monitoring sites and to establish new sites, these linking methods must be as informative, reliable, affordable, and maintainable as possible, and should be supplemented by near real-time remote sensing data. The proposed novel meta-network will enable the detection of emergent patterns that would not be visible from isolated analyses of individual sites. In addition, the near real-time availability of data will facilitate predictions of current forest conditions (nowcasts), which are urgently needed for research and decision making in the face of rapid climate change. We call for international and interdisciplinary efforts in this direction.

Health and wellbeing implications of adaptation to flood risk

Adaptation strategies to ameliorate the impacts of climate change are increasing in scale and scope around the world, with interventions becoming a part of daily life for many people. Though the implications of climate impacts for health and wellbeing are well documented, to date, adaptations are largely evaluated by financial cost and their effectiveness in reducing risk. Looking across different forms of adaptation to floods, we use existing literature to develop a typology of key domains of impact arising from interventions that are likely to shape health and wellbeing. We suggest that this typology can be used to assess the health consequences of adaptation interventions more generally and argue that such forms of evaluation will better support the development of sustainable adaptation planning.

Overcoming the coupled climate and biodiversity crises and their societal impacts

Earth's biodiversity and human societies face pollution, overconsumption of natural resources, urbanization, demographic shifts, social and economic inequalities, and habitat loss, many of which are exacerbated by climate change. Here, we review links among climate, biodiversity, and society and develop a roadmap toward sustainability. These include limiting warming to 1.5°C and effectively conserving and restoring functional ecosystems on 30 to 50% of land, freshwater, and ocean "scapes." We envision a mosaic of interconnected protected and shared spaces, including intensively used spaces, to strengthen self-sustaining biodiversity, the capacity of people and nature to adapt to and mitigate climate change, and nature's contributions to people. Fostering interlinked human, ecosystem, and planetary health for a livable future urgently requires bold implementation of transformative policy interventions through interconnected institutions, governance, and social systems from local to global levels.

The carbon sink of secondary and degraded humid tropical forests

The globally important carbon sink of intact, old-growth tropical humid forests is declining because of climate change, deforestation and degradation from fire and logging^1-3. Recovering tropical secondary and degraded forests now cover about 10% of the tropical forest area⁴, but how much carbon they accumulate remains uncertain. Here we quantify the aboveground carbon (AGC) sink of recovering forests across three main continuous tropical humid regions: the Amazon, Borneo and Central Africa^5,6. On the basis of satellite data products^4,7, our analysis encompasses the heterogeneous spatial and temporal patterns of growth in degraded and secondary forests, influenced by key environmental and anthropogenic drivers. In the first 20 years of recovery, regrowth rates in Borneo were up to 45% and 58% higher than in Central Africa and the Amazon, respectively. This is due to variables such as temperature, water deficit and disturbance regimes. We find that regrowing degraded and secondary forests accumulated 107 Tg C year^-1 (90-130 Tg C year^-1) between 1984 and 2018, counterbalancing 26% (21-34%) of carbon emissions from humid tropical forest loss during the same period. Protecting old-growth forests is therefore a priority. Furthermore, we estimate that conserving recovering degraded and secondary forests can have a feasible future carbon sink potential of 53 Tg C year^-1 (44-62 Tg C year^-1) across the main tropical regions studied.

Pandemic urban development is leading us away from nature

Recovery plans in Europe in the COVID-19 pandemic era have stimulated construction-led development, which has eclipsed nature-based agendas in terms of scale, size, and policy. One estimate is that only 0.3% of spending on urban infrastructure globally is directed towards various nature-based solutions and other ecosystem efforts supporting human well-being. In the future we will urgently need to employ nature-based approaches in crisis management for the power and potential of nature to be fully employed in pursuit of urban recovery. We strongly recommend that nature-based approaches be an explicit requirement to secure funding for future recovery plans.

Transformative adaptation through nature-based solutions: a comparative case study analysis in China, Italy, and Germany

This paper explores how claims for transformative adaptation toward more equitable and sustainable societies can be assessed. We build on a theoretical framework describing transformative adaptation as it manifests across four core elements of the public-sector adaptation lifecycle: vision, planning, institutional frameworks, and interventions. For each element, we identify characteristics that can help track adaptation as transformative. Our purpose is to identify how governance systems can constrain or support transformative choices and thus enable targeted interventions. We demonstrate and test the usefulness of the framework with reference to three government-led adaptation projects of nature-based solutions (NBS): river restoration (Germany), forest conservation (China), and landslide risk reduction (Italy). Building on a desktop study and open-ended interviews, our analysis adds evidence to the view that transformation is not an abrupt system change, but a dynamic complex process that evolves over time. While each of the NBS cases fails to fulfill all the transformation characteristics, there are important transformative elements in their visions, planning, and interventions. There is a deficit, however, in the transformation of institutional frameworks. The cases show institutional commonalities in multi-scale and cross-sectoral (polycentric) collaboration as well as innovative processes for inclusive stakeholder engagement; yet, these arrangements are ad hoc, short-term, dependent on local champions, and lacking the permanency needed for upscaling. For the public sector, this result highlights the potential for establishing cross-competing priorities among agencies, cross-sectoral formal mechanisms, new dedicated institutions, and programmatic and regulatory mainstreaming.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10113-023-02066-7.

Estimating the social value of nature-based solutions in European cities

By implementing nature-based solutions (NBS), cities generate value for their residents, such as health and wellbeing. We estimate the aggregate social value to urban residents of 85 NBS projects implemented across Europe and find that the majority yield attractive social returns on investment. We offer a new metric to support investments for NBS by public and private actors for whom social value creation to residents is a core objective.