Cash for carbon: A randomized trial of payments for ecosystem services to reduce deforestation

What Happens When Payments End? Fostering Long-Term Behavior Change With Financial Incentives

Financial incentives are widely used to get people to adopt desirable behaviors. Many small landholders in developing countries, for example, receive multiyear payments to engage in conservation behaviors, and the hope is that they will continue to engage in these behaviors after the program ends. Although effective in the short term, financial incentives rarely lead to long-term behavior change because program participants tend to revert to their initial behaviors soon after the payments stop. In this article, we propose that four psychological constructs can be leveraged to increase the long-term effectiveness of financial-incentive programs: motivation, habit formation, social norms, and recursive processes. We review successful and unsuccessful behavior-change initiatives involving financial incentives in several domains: public health, education, sustainability, and conservation. We make concrete recommendations on how to implement the four above-mentioned constructs in field settings. Finally, we identify unresolved issues that future research might want to address to advance knowledge, promote theory development, and understand the psychological mechanisms that can be used to improve the effectiveness of incentive programs in the real world.

Do you really believe that? The effect of economic incentives on the acceptance of real-world data in a polarized context

Attitudes and expectations towards others are major drivers of political polarization. However, there is limited understanding of their relevance when decisions with high stakes are taken. In this study, we compare self-reported attitudes against economically incentivized estimates of data coming from official sources and offer participants financial rewards for accuracy. Our methodology yields three principal findings. (i) Extreme attitudes from a small partisan subgroup primarily account for the observed partisan divide; this subgroup diminishes when incentivized estimates are considered. (ii) There is a weak correlation between economically incentivized and unincentivized measures within individual respondents. (iii) We introduce a novel metric for assessing perceived polarization. This metric allows participants to estimate data points for those with opposing political views, rewarding accurate predictions financially. Interestingly, this measure of perceived polarization correlates with attitudes but not with incentivized data estimates. This is in line with the concept of 'false polarization', attributing polarization more to expectations towards others than to genuine differences. These findings challenge the reliability of standard attitude surveys and suggest avenues for mitigating perceived polarization in contentious issues.

Payments for ecosystem services programs: A global review of contributions towards sustainability

Payments for ecosystem services programs (PESPs) are increasingly being adopted globally to enhance sustainability outcomes. There are also hundreds of studies yearly on various aspects of PESPs, but research on their contributions to sustainability of communities and the ecosystems they depend upon at the global scale are rare. Our global review explores twelve key characteristics of PESPs at three different phases (inputs - implementation - outputs and outcomes) and their relationship types of these characteristics to sustainability outcomes. To do so, we review 376 peer-review journal articles on PESPs, and test three hypotheses related to these relationships. Our findings confirm that the relationships between each of these characteristics and sustainability outcomes are bidirectional and/or multidirectional to some extent and can be positive, negative or both, depending on specific cases and research methods used to study these relationships. The findings also disclose that separating one characteristic as the primary causal factor in any relationship or outcome is not easy as relevant characteristics are linked in a complex network. Thereby, determining key characteristics of PESPs that drive relationships for the sake of sustainability is important. Through analyzing relationships between PESP characteristics, this study offers a series of suggestions to further aid the contributions of PESPs' contributions to sustainability in the future.

Sustainable poverty alleviation through forests: Pathways and strategies

Forests are the most productive terrestrial ecosystems across the world. They can play both a direct and indirect role in global poverty alleviation through their social, economic and environmental functions. However, the potential of forests in poverty alleviation is underestimated to a great extent. Sustainability, the most essential advantage and characteristic of forests for poverty alleviation, has not been fully recognized. To that end, we propose the concept of sustainable poverty alleviation through forests (SPAF). This concept shifts the vision of poverty alleviation through forests from a narrow focus on subsistence and livelihood to a sustainable poverty alleviation that promotes all dimensions of human development. There is abundant evidence that forests can at least contribute to sustainable poverty alleviation through a synergy of seven pathways: subsistence materials, health, income, employment, women's empowerment, climate change mitigation and biodiversity, which are highly consistent with the United Nations Sustainable Development Goals. SPAF also faces enormous implementation challenges, so a sustainable global strategy is urgently needed to provide direction for worldwide poverty alleviation at the crossroads of nature and humanity.

The social value of offsets

It is unclear how much carbon should be stored in temporary and risky offsets to compensate one ton of CO₂ emissions. Here we cast the social value of an offset (SVO), measured in terms of economic damages avoided, as a well-defined fraction of the social cost of carbon reflecting offset duration, and risks of non-additionality and failure. The SVO reflects the value of temporary storage, and overcomes shortcomings in the climate science and economics of previous contributions^1-4. The SVO is policy relevant. An efficient net-zero policy will consist of offsets if their SVO/cost ratio exceeds the benefit/cost ratio of alternatives. The SVO yields an indicator of the equivalence of offsets to permanent carbon storage measured by the ratio of the SVO to the social cost of carbon. We provide a matrix of equivalence factors for different risks, permanence and climate scenarios. Estimation yields a rule of thumb: one offset sequestering one ton for 50 years is equivalent to between 0.33 and 0.5 tons permanently locked away. Equivalence offers a means of replacing perpetual offset contracts by simpler, easy to monitor short-term contracts, has applications to carbon life cycle analysis⁵ and the valuation of carbon debts⁶, and can be the basis of comparing offsets of different qualities in the voluntary and compliance markets.

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.

Payments for ecosystem services did not crowd out pro-environmental behavior: Long-term experimental evidence from Uganda

Payments for ecosystem services (PES) are increasingly being implemented worldwide as conservation instruments that provide conditional economic incentives to landowners for a prespecified duration. However, in the psychological and economic literature, critics have raised concerns that PES can undermine the recipient's intrinsic motivation to engage in pro-environmental behavior. Such "crowding out" may reduce the effectiveness of PES and may even worsen conservation outcomes once programs are terminated. In this study, we harnessed a randomized controlled trial that provided PES to land users in Western Uganda and evaluated whether these incentives had a persistent effect on pro-environmental behavior and its underlying behavioral drivers 6 y after the last payments were made. We elicited pro-environmental behavior with an incentivized, experimental measure that consisted of a choice for respondents between more and less environmentally friendly tree seedlings. In addition to this main outcome, survey-based measures for underlying behavioral drivers captured self-efficacy beliefs, intrinsic motivation, and perceived forest benefits. Overall, we found no indications that PES led to the crowding out of pro-environmental behavior. That is, respondents from the treatment villages were as likely as respondents from the control villages to choose environmentally friendly tree seedlings. We also found no systematic differences between these two groups in their underlying behavioral drivers, and nor did we find evidence for crowding effects when focusing on self-reported tree planting behavior as an alternative outcome measure.

A PES framework coupling socioeconomic and ecosystem dynamics from a sustainable development perspective

Payments for ecosystem services (PES) are becoming a global ecological protection strategy used to promote sustainable social and economic development. However, the current PES research and applications are often local and one-sided. The lack of a unified framework for PES results in a high policy cost and low ecological and social benefits. A large number of local PES experiences need to be comprehensively analyzed to construct a unified PES framework, which can provide support for the implementation and optimization of nature conservation policy in different regions of the world. Here, we combined natural language processing methods to analyze 1919 global studies on PES. We obtained the topics and spatiotemporal distributions of PES, as well as the compensation modes of hotspot ecosystem services in 114 countries worldwide. PES have been studied in 80% of the world (excluding Antarctica), but the research topics and distributions are very uneven. We found a disconnection between PES socioeconomic strategies and knowledge of natural ecosystem dynamics. Therefore, the knowledge and experience of PES must be exchanged globally, and PES need to be further integrated with the sustainable development goal (SDG) framework. We propose a PES framework that couples socioeconomic and ecosystem dynamics and be oriented toward sustainable development to make comprehensive management decisions. On this basis, a consistent PES solution may be provided for future theoretical research and implementation strategies of conservation.

Catalyzing success in community-based conservation

Efforts to devolve rights and engage Indigenous Peoples and local communities in conservation have increased the demand for evidence of the efficacy of community-based conservation (CBC) and insights into what enables its success. We examined the human well-being and environmental outcomes of a diverse set of 128 CBC projects. Over 80% of CBC projects had some positive human well-being or environmental outcomes, although just 32% achieved positive outcomes for both (i.e., combined success). We coded 57 total national-, community-, and project-level variables and controls from this set, performed random forest classification to identify the variables most important to combined success, and calculated accumulated local effects to describe their individual influence on the probability of achieving it. The best predictors of combined success were 17 variables suggestive of various recommendations and opportunities for conservation practitioners related to national contexts, community characteristics, and the implementation of various strategies and interventions informed by existing CBC frameworks. Specifically, CBC projects had higher probabilities of combined success when they occurred in national contexts supportive of local governance, confronted challenges to collective action, promoted economic diversification, and invested in various capacity-building efforts. Our results provide important insights into how to encourage greater success in CBC.

A global evaluation of the effectiveness of voluntary REDD+ projects at reducing deforestation and degradation in the moist tropics

Reducing emissions from deforestation and forest degradation (REDD+) projects aim to contribute to climate change mitigation by protecting and enhancing carbon stocks in tropical forests, but there have been no systematic global evaluations of their impact. We used a new data set for tropical humid forests and a standardized evaluation approach (based on pixel matching) to quantify the performance of a representative sample of 40 voluntary REDD+ projects in 9 countries certified under the Verified Carbon Standard (VCS). In the first 5 years of implementation, deforestation within project areas was reduced by 47% (95% confidence interval [CI]: 24-68) compared with matched counterfactual pixels, and degradation rates were 58% lower (95% CI: 49-63). Reductions were small in absolute terms but greater in sites located in high-deforestation settings and did not appear to be substantially undermined by leakage activities in forested areas within 10 km of project boundaries. At the 26th Conference of the Parties of the United Nations Framework Convention on Climate Change, the international community renewed its commitment to tackling tropical deforestation as a nature-based solution to climate change. Our results indicate that incentivizing forest conservation through voluntary site-based projects can slow tropical deforestation and highlight the particular importance of prioritizing financing for areas at greater risk of deforestation.

Improved household living standards can restore dry tropical forests

Despite multiple approaches over the last several decades to harmonize conservation and development goals in the tropics, forest-dependent households remain the poorest in the world. Durable housing and alternatives to fuelwood for cooking are critical needs to reduce multi-dimensional poverty. These improvements also potentially reduce pressure on forests and alleviate forest degradation. We test this possibility in dry tropical forests of the Central Indian Highlands where tribal and other marginalized populations rely on forests for energy, construction materials, and other livelihood needs. Based on a remotely sensed measure of forest degradation and a 5000 household survey of forest use, we use machine learning (causal forests) and other statistical methods to quantify treatment effects of two improved living standards-alternatives to fuelwood for cooking and non-forest-based housing material-on forest degradation in 1, 2, and 5 km buffers around 500 villages. Both improved living standards had significant treatment effects (-0.030 ± 0.078, -0.030 ± 0.023, 95% CI), respectively, with negative values indicating less forest degradation, within 1 km buffers around villages. Treatment effects were lower with increasing distance from villages. Results suggest that improved living standards can both reduce forest degradation and alleviate poverty. Forest restoration efforts can target improved living standards for local communities without conflicts over land tenure or taking land out of production to plant trees.

The payment scheme for ecosystem services in the coastal city based on the ecosystem services value and current payment efficiency: a case study in Jimo of Qingdao city, China

The reasonable strategies of payment for ecosystem services (PES) play a key role in solving the contradiction between ecological protection and economic development in coastal cities. However, at present, the payment efficiency is relatively low and the determination method of PES is lack. Therefore, in this study, the Jimo district of Qingdao city in China, a typical coastal city, was selected as study area, and the equivalent factor method and marine ecological capital assessment method were used to obtain terrestrial and marine ecosystem services value (ESV) and its tempo-spatial variations from 2010 to 2018. Moreover, the payment efficiency of the sea area and 15 towns over 8 years was measured using the Super-efficient SBM-DEA model based on undesired output. ESV presented a clear reduction over 8 years. The marine ecosystem provided the main service value, and waste treatment, water regulation, and soil formation were the top 3 main functions in the land ecosystem. Regulating services provided the highest component among all functions. The high-value areas were mainly distributed in the northeast and northwest regions and the low-value areas were in the south-central regions. The average payment efficiency of the sea area and 15 towns over 8 years shown a stable trend at a low level. On the basis of the evaluation of ESV and efficiency, a new possible payment scheme including payment order and quota was proposed. The total quota of marine ecosystem was 5.226 billion RMB (88% of the total) and of terrestrial ecosystem was 0.713 billion RMB. Tian Heng, Jin Kou, Yi Fengdian, and Ling Shan are the first 4 priority towns, with compensation amounts of 0.205, 0.083, and 0.063 billion RMB respectively, while the last 3 towns are Tong Ji, Huan Xiu, and Chao Hai accounting for 6.02% of the total. The theoretical payment total quota was 5.939 billion RMB, and which accounted for a low proportion of local GDP. The study can provide some recommendations for making the reasonable and feasible payment schemes for ecosystem services in coastal city, and it is feasible in the practice of ecological environment protection and sustainable development.

The Effects of Payment for Environmental Services on Environmental Improvement and Poverty Reduction: A Meta-Regression Analysis

Based on the empirical literature of the payments for environmental services (PES) projects for the environmental improvement and poverty reduction, this paper uses a meta-regression analysis method to study whether PES can achieve the effects of improving environmental quality and reducing poverty levels. For the meta-regression analysis, the literature was mainly searched by the Web of Science core journal database. The explanatory variables of meta-regression analysis are the hypothesis and related features of the models in the original literature by generally taking the binary dummy variables or categorical variables. The dependent variables used in this paper are environmental improvement and poverty reduction. The results show that PES projects based on private ownership rights are more conducive to poverty reduction and environmental improvement. If the country is a buyer of a PES project, it is more likely to achieve the effects of environmental enhancement and poverty alleviation. PES projects based on local conditions can also achieve a win–win situation for the two effects. The effects are more effective as policy implementation time is extended. The findings suggest that in developing countries, the government should set different PES projects according to different regions conditions, to promote project implementation through individual voluntary participation, and to achieve the dual purpose of environmental governance and poverty alleviation based on the expectation of long-term implementation of participant projects.

An integrative framework for transformative social change: a case in global wildlife trade

To achieve a sustainable future, it is imperative to transform human actions collectively and underlying social structures. Decades of research in social sciences have offered complementary insights into how such transformations might occur. However, these insights largely remain disjunct and of limited scope, such that strategies for solving global environmental challenges remain elusive. There is a need to integrate approaches focusing on individuals and social structures to understand how individual actions influence and are in turn influenced by social structures and norms. In this paper, we synthesize a range of insights across different schools of thought and integrate them in a novel framework for transformative social change. Our framework explains the relationships among individual behaviors, collective actions, and social structures and helps change agents guide societal transitions toward environmental sustainability. We apply this framework to the global wildlife trade-which presents several distinct challenges of human actions, especially amidst the Covid-19 pandemic-and identify pathways toward transformative change. One key distinction we make is between different individual actions that comprise the practice itself (e.g., buying wildlife products; private action) and those that push for a broader system change in practice (e.g., signaling (dis)approval for wildlife consumption; social-signaling action, and campaigning for policies that end unsustainable wildlife trade; system-changing action). In general, transformative change will require an integrative approach that includes both structural reforms and all three classes of individual action.

Upscaling tropical restoration to deliver environmental benefits and socially equitable outcomes

The UN Decade on Ecosystem Restoration offers immense potential to return hundreds of millions of hectares of degraded tropical landscapes to functioning ecosystems. Well-designed restoration can tackle multiple Sustainable Development Goals, driving synergistic benefits for biodiversity, ecosystem services, agricultural and timber production, and local livelihoods at large spatial scales. To deliver on this potential, restoration efforts must recognise and reduce trade-offs among objectives, and minimize competition with food production and conservation of native ecosystems. Restoration initiatives also need to confront core environmental challenges of climate change and inappropriate planting in savanna biomes, be robustly funded over the long term, and address issues of poor governance, inadequate land tenure, and socio-cultural disparities in benefits and costs. Tackling these issues using the landscape approach is vital to realising the potential for restoration to break the cycle of land degradation and poverty, and deliver on its core environmental and social promises.

Subjective modeling choices and the robustness of impact evaluations in conservation science

Arbitrary modeling choices are inevitable in scientific studies. Yet, few empirical studies in conservation science report the effects these arbitrary choices have on estimated results. I explored the effects of subjective modeling choices in the context of counterfactual impact evaluations. Over 5000 candidate models based on reasonable changes in the choice of statistical matching algorithms (e.g., genetic and nearest distance mahalanobis matching), the parametrization of these algorithms (e.g., number of matches), and the inclusion of specific covariates (e.g., distance to nearest city, slope, or rainfall) were valid for studying the effect of Virunga National Park in Democratic Republic of the Congo on changes in tree cover loss and carbon storage over time. I randomly picked 2000 of the 5000 candidate models to determine how much and which subjective modeling choices affected the results the most. All valid models indicated that tree cover loss decreased and carbon storage increased in Virunga National Park from 2000 to 2019. Nonetheless, the order of magnitude of the estimates varied by a factor of 3 (from -4.78 to -13.12 percentage points decrease in tree cover loss and from 20 to 46 t Ce/ha for carbon storage). My results highlight that modeling choices, notably the choice of the matching algorithm, can have significant effects on point estimates and suggest that more structured robustness checks are a key step toward more credible findings in conservation science.

Using big data for evaluating development outcomes: A systematic map

BACKGROUND

Policy makers need access to reliable data to monitor and evaluate the progress of development outcomes and targets such as sustainable development outcomes (SDGs). However, significant data and evidence gaps remain. Lack of resources, limited capacity within governments and logistical difficulties in collecting data are some of the reasons for the data gaps. Big data-that is digitally generated, passively produced and automatically collected-offers a great potential for answering some of the data needs. Satellite and sensors, mobile phone call detail records, online transactions and search data, and social media are some of the examples of big data. Integrating big data with the traditional household surveys and administrative data can complement data availability, quality, granularity, accuracy and frequency, and help measure development outcomes temporally and spatially in a number of new ways.The study maps different sources of big data onto development outcomes (based on SDGs) to identify current evidence base, use and the gaps. The map provides a visual overview of existing and ongoing studies. This study also discusses the risks, biases and ethical challenges in using big data for measuring and evaluating development outcomes. The study is a valuable resource for evaluators, researchers, funders, policymakers and practitioners in their effort to contributing to evidence informed policy making and in achieving the SDGs.

OBJECTIVES

Identify and appraise rigorous impact evaluations (IEs), systematic reviews and the studies that have innovatively used big data to measure any development outcomes with special reference to difficult contexts.

SEARCH METHODS

A number of general and specialised data bases and reporsitories of organisations were searched using keywords related to big data by an information specialist.

SELECTION CRITERIA

The studies were selected on basis of whether they used big data sources to measure or evaluate development outcomes.

DATA COLLECTION AND ANALYSIS

Data collection was conducted using a data extraction tool and all extracted data was entered into excel and then analysed using Stata. The data analysis involved looking at trends and descriptive statistics only.

MAIN RESULTS

The search yielded over 17,000 records, which we then screened down to 437 studies which became the foundation of our systematic map. We found that overall, there is a sizable and rapidly growing number of measurement studies using big data but a much smaller number of IEs. We also see that the bulk of the big data sources are machine-generated (mostly satellites) represented in the light blue. We find that satellite data was used in over 70% of the measurement studies and in over 80% of the IEs.

AUTHORS' CONCLUSIONS

This map gives us a sense that there is a lot of work being done to develop appropriate measures using big data which could subsequently be used in IEs. Information on costs, ethics, transparency is lacking in the studies and more work is needed in this area to understand the efficacies related to the use of big data. There are a number of outcomes which are not being studied using big data, either due to the lack to applicability such as education or due to lack of awareness about the new methods and data sources. The map points to a number of gaps as well as opportunities where future researchers can conduct research.

Corporate Payments for Ecosystem Services in Theory and Practice: Links to Economics, Business, and Sustainability

Few Payments for Ecosystem Services (PES) schemes are financed voluntarily by corporations. This is perhaps unsurprising, given that limited literature on the theory and practice of PES has a dedicated focus on businesses. This article unifies the PES and business literatures in order to address the awareness and management challenges that corporations face in engaging in PES. First, it shows how corporations fit into the economic theory that underpins PES, demonstrating that corporate-financed PES schemes can exhibit a diversity and hybridity of Coasean and Pigouvian characteristics. Second, it shows how PES fits into corporate sustainability theory, demonstrating how PES can help companies achieve synergies across the economic, environmental, and social tenets of the triple bottom line; for example, by helping gain social license to operate from adjacent communities, or by using PES to meet sustainability reporting requirements related to emissions and water management. Third, it shows the different PES options available to firms based on their industrial sector, operating practices, and business strategies. The options with higher potential are maintenance and enhancement of production inputs across the supply chain, and carbon offsetting and insetting to help meet climate change mitigation regulations and avoid fines. Fourth, it identifies lessons learned when transitioning from theory to practice by synthesising the latest empirical research on corporate-financed PES schemes—considering exactly what these ‘should’ or ‘could’ resemble, for example, in terms of their additionality, conditionality, permanence, co-benefits, budgeting, and bargaining. Examples are drawn from corporate-financed schemes in forests and watersheds across Africa, Asia, Europe, Latin America, and North America. The article concludes that these schemes remain small in number and size, but have significant potential to increase—and this can be aided by future research on corporate motives, understandings, and actions on PES.

Experimental Evidence on the Impact of Payments and Property Rights on Forest User Decisions

Clearing forests for swidden agriculture, despite providing food to millions of farmers in the tropics, can be a major driver of deforestation. Payments for ecosystem services schemes can help stop swidden agriculture-induced forest loss by rewarding forest users for maintaining forests. Clear and secure property rights are a key prerequisite for the success of these payment schemes. In this study, we use a novel iterative and dynamic game in Madagascar and Kenya to examine farmer responses to individual and communal rights to forestlands, with and without financial incentives, in the context of swidden agricultural landscapes. We find that farmer pro conservation behaviour, defined by the propensity to keep forests or fallows on their lands, as well as the effects of land tenure and conservation incentive treatments on such behaviour, differ across the two contexts. The average percentages of land left forest/fallow in the game are 65 and 35% in Kenya and Madagascar, respectively. Individual ownership significantly improves decisions to preserve forests or leave land fallow in Madagascar but has no significant effect in Kenya. Also, the effect of the individual tenure treatment varies across education and wealth levels in Madagascar. Subsidy increases farmers' willingness to support conservation interests in both countries, but its effect is four times greater in Kenya. We find no interaction effects of the two treatments in either country. We conclude that the effectiveness of financial incentives for conservation and tenure reform in preserving forestland vary significantly across contexts. We show how interactive games can help develop a more targeted and practical approach to environmental policy.

Citizen monitoring promotes informed and inclusive forest governance in Liberia

Global forest loss depends on decisions made in the rural, often poor communities living beside the Earth's remaining forests. Governance problems in these forest-edge communities contribute to rapid deforestation and household vulnerability. In coordination with experimental studies in 5 other countries, we evaluate a program that recruits, trains, and deploys citizens to monitor communal forestland in 60 communities in rural Liberia. The year-long intervention is designed to promote more informed and inclusive resource governance, so that that citizens' preferences (and not just leaders' interests) are reflected in forest management. In our control communities, households are uninformed and disengaged; leaders' authority is unchecked. The program both engages and mobilizes community members: households are better informed and participate more in the design and enforcement of rules around forest use. They also report receiving more material benefits from outside investors' activities in their community forests. The chiefs who lead these communities attest to strengthened accountability. Using both on-the-ground environmental assessments and remotely sensed data, we find no effects on forest use or deforestation. Households do not favor more conservation, and, thus, more inclusive management does not reduce forest use. Conservation likely requires compensating community members for foregoing forest use; citizen monitoring, we argue, could ensure that such schemes enjoy popular support and do not just benefit local elites.

Additionality and Leakage Resulting from PES Implementation? Evidence from the Ecuadorian Amazonia

Payments for Environmental Services (PES) are instruments which seem well suited for forest conservation. However, their impact on reducing deforestation might be weakened by negligible additionality and leakage effects; the first refers to the low variation in net deforestation rates even in the absence of PES, and the second refers to the displaced deforestation behavior to other areas not covered by PES. For the case of Ecuador, we examine both issues by assessing the historical deforestation trend of selected PES-enrolled areas and that of their adjacent areas to identify deforestation patterns before and after PES implementation. We analyze the additional effect of PES on reducing deforestation by comparison to a baseline as well as to comparable reference sites at two different spatial scales. We also analyze potential leakage effects of PES by comparing deforestation development in adjacent areas. We show that PES has achieved marginally low conservation impacts in enrolled areas with an average difference in net deforestation rates of 0.02 percent points over a period of 28 years. Overall, PES-enrolled areas depict lower annual net deforestation rates than unenrolled areas, albeit at a negligible rate, and there is also some evidence that deforestation decreased in adjacent areas after PES implementation. Additionally, there exists a statistically significant linear increasing deforestation trend in adjacent areas as distance increases from the PES-enrolled area. Our empirical results, however, raise the suspicion that the choice of PES-enrolled areas might have been influenced by self-selection.

Can community monitoring save the commons? Evidence on forest use and displacement

Rapid deforestation is a major driver of greenhouse-gas emissions (1). One proposed policy tool to halt deforestation is community forest management. Even though communities manage an increasing proportion of the world's forests, we lack good evidence of successful approaches to community forest management. Prior studies suggest that successful approaches require a number of "design conditions" to be met. However, causal evidence on the effectiveness of individual design conditions is scarce. This study isolates one design condition, community-led monitoring of the forest, and provides causal evidence on its potential to reduce forest use. The study employs a randomized controlled trial to investigate the impact of community monitoring on forest use in 110 villages in Uganda. We explore the impact of community monitoring in both monitored and unmonitored areas of the forest, using exceptionally detailed data from on-the-ground measurements and satellite imagery. Estimates indicate that community monitoring does not affect our main outcome of interest, a forest-use index. However, treatment villages see a relative increase in forest loss outside of monitored forest areas compared to control villages. This increase is seen both in nonmonitored areas adjacent to treatment villages and in nonmonitored areas adjacent to neighboring villages not included in the study. We tentatively conclude that at least part of the increase in forest loss in nonmonitored areas is due to displacement of forest use by members of treatment villages due to fear of sanctions. Interventions to reduce deforestation should take this potentially substantial effect into consideration.

The impacts of agroforestry interventions on agricultural productivity, ecosystem services, and human well-being in low- and middle-income countries: A systematic review

Background

Agroforestry, the intentional integration of trees or other woody perennials with crops or livestock in production systems, is being widely promoted as a conservation and development tool to help meet the 2030 UN Sustainable Development Goals. Donors, governments, and nongovernmental organizations have invested significant time and resources into developing and promoting agroforestry policies and programs in low- and middle-income countries (LMICs) worldwide. While a large body of literature on the impacts of agroforestry practices in LMICs is available, the social-ecological impacts of agroforestry interventions is less well-studied. This knowledge gap on the effectiveness of agroforestry interventions constrains possibilities for evidence-based policy and investment decisions to advance sustainable development objectives.

Objectives

The primary objective of this Campbell systematic review was to synthesize the available evidence on the impacts of agroforestry interventions in LMICs on agricultural productivity, ecosystem services, and human well-being. The secondary objectives were to identify key pathways through which agroforestry interventions lead to various outcomes and how the interventions affect different sub-groups of the population.

Search Methods

This review is based on a previously created evidence and gap map (EGM) of studies evaluating the impacts of agroforestry practices and interventions on agricultural productivity, ecosystem services, and human well-being. We included published and unpublished literature in the English language covering the period between 2000 and October 20, 2017. We searched six academic databases and 19 organization websites to identify potentially relevant studies. The search was conducted for our EGM in mid-2017, and we did not conduct an additional search for this systematic review.

Selection Criteria

We included randomized control trials (RCTs) and quasi-experimental studies assessing the effect of an agroforestry intervention on at least one outcome measure of agricultural productivity, ecosystem services, or human well-being for farmers and their farmland in LMICs. Agroforestry interventions include any program or policy designed to promote and support the adoption or maintenance of agroforestry practices, which include trees on farms, silvopasture, shade-grown crops, and homegardens with trees, among others. Moreover, the studies needed to include a nonagroforestry comparator, such as conventional agriculture or forestry systems or a before-after comparison.

Data Collection and Analysis

We used a standardized data extraction spreadsheet to extract details about each included study. We also used a standardized form to assess risk of bias for each of the included studies in this SR. Meta-analysis techniques were used to combine and synthesize effect size estimates for the outcomes measures that had sufficient data. We used a random effects models for the meta-analyses and use Hedge's g (difference in means divided by the pooled standard deviation) to report effect size estimates. The outcomes without enough evidence for meta-analysis were discussed narratively.

Main Results

We identified 11 studies across nine countries, all of which used quasi-experimental methods. Overall, the quality of the evidence base was assessed as being low. Studies were rated as having high or critical risk of bias if they failed to convincingly address more than one of the main potential sources of bias, namely selection bias, group equivalence, and spillover effects. Given the low number of studies and the high risk of bias of the evidence base, the results of this SR are limited and should be considered a baseline for future work. The results of the meta-analysis for impacts on yields indicated that agroforestry interventions overall may lead to a large, positive impact on yield (Hedge's g = 1.16 [-0.35, 2.67] (p = .13)), though there was high heterogeneity in the results (I ² = 98.99%, τ 2  = 2.94, Q(df = 4)  = 370.7). There were positive yield impacts for soil fertility replenishment practices, including incorporating trees in agricultural fields and improved fallow practices in fields where there are severe soil fertility issues. In other cases, incorporating trees into the production system reduced productivity and took land out of production for conservation benefits. These systems generally used an incentive provision scheme to economically offset the reductions in yields. The result of the meta-analysis on income suggests that agroforestry interventions overall may lead to a small, positive impact on income (Hedge's g = 0.12 [-0.06, 0.30] (p = .20)), with moderately high heterogeneity in the results (I ² = 75.29%, τ 2  = 0.04, Q(df = 6) = 19.16). In cases where improvement yields were reported, there were generally attendant improvements in income. In the cases where payments were provided to offset the potential loss in yields, incomes also generally improved, though there were mixed results for the certification programs and the tenure security permitting scheme. One program, which study authors suggested may have been poorly targeted, had negative yield impacts. There was not enough comparable evidence to quantitatively synthesize the impacts of agroforestry interventions on nutrition and food security outcomes, though the results indicted positive or neutral impacts on dietary diversity and food intake were likely. Surprisingly, there was little evidence on the impacts of agroforestry interventions on environmental outcomes, and there was no consistency of environmental indicator variables used. However, what has been studied indicates that the environmental benefits are being achieved to at least some extent, consistent with the broader literature on agroforestry practices. The evidence base was insufficient to evaluate the interaction between environmental and social impacts. Several studies explicitly considered variable impacts across different population sub-groups, including differential impacts on small-holders versus large-holders, on woman-headed households versus male-headed households, and on richer groups versus poorer groups. Small-holder farmers typically experienced the most positive effect sizes due to the agroforestry interventions. Women and poorer groups had mixed outcomes relative to men and richer households, highlighting the importance of considering these groups in intervention design.

Authors' Conclusions

There is limited evidence of the impacts of agroforestry interventions, restricting our ability to draw conclusions on the effect sizes of different intervention types. The existing evidence forms a baseline for future research and highlights the importance of considering equity and socio-economic factors in determining suitable intervention design. Some key implications for practice and policy include investing in programs that include pilot programs, funding for project evaluation, and that address key equity issues, such as targeting to smallholders, women, poor, and marginalized groups. Funding should also be given to implementing RCTs and more rigorous quasi-experimental impact evaluations of agroforestry interventions over longer time-periods to collect robust evidence of the effectiveness of various schemes promoting agroforestry practices.

Current carbon prices do not stack up to much land use change, despite bundled ecosystem service co-benefits

Biological sources of carbon sequestration such as revegetation have been highlighted as important avenues to combat climate change and meet global targets by the global community including the Paris Climate Agreement. However, current and projected carbon prices present a considerable barrier to broad-scale adoption of tree planting as a key mitigation strategy. One avenue to provide additional economic and environmental incentives to encourage wider adoption of revegetation is the bundling or stacking of additional co-beneficial ecosystem services that can be realized from tree planting. Using the World's largest land-based carbon credit trading scheme, the Australian Emissions Reduction Scheme (ERF), we examine the potential for three pairs of ecosystem services, where the carbon sequestration value of land use change is paired with an additional co-benefit with strong prospects for local tangible benefits to land owners/providers. Two cases consider agricultural provisioning values that can be realized by the landowners in higher returns: increased pollination services and reduced lamb mortality. The third case examined payments for tree plantings along riparian buffers, with payments to farmers by a water utility who realizes the benefit from reduced treatment cost due to water quality improvements. Economic incentives from these co-benefit case studies were found to be mixed, with avoided treatment costs from water quality paired with carbon payments the most promising, while pollination and reduced lamb mortality paired with carbon payments were unable to bridge the economic gap except under the most optimistic assumptions. We conclude that the economics case for significant land use change are likely to be geographically dispersed and only viable in relatively niche landscape positions in high establishment, high opportunity cost areas even when carbon payments are augmented with the value of co-benefits classified as providing direct and local benefits.

Estimation of Citizens’ Willingness to Pay for the Implementation of Payment for Local Forest Ecosystem Services: The Case of Taxes and Donations

The purpose of this study is to determine a valid strategy for implementing payment for the local forest ecosystem services (local forest PES) by considering citizens’ willingness to pay (WTP) and the resource types utilized (taxes and donations). A total of 1000 citizens responded to an online survey, which consisted of questions related to respondents’ socio-demographics, predicting factors (i.e., political orientation, personal tie to the region) of their willingness to pay (WTP), and their willingness to pay for a bundle of 10 different forest ecosystem services (ESs) in the region of the Yeoninsan provincial park in Gapyeong-gun, Gyeonggi-do, South Korea. The estimation of the respondents’ WTP for the promotion of the forest management activities, which enhances the ES bundle of the local forest, was 14,315–20,216 KRW (12.75–18.00 USD) per year in taxes and 12,258–26,518 KRW (10.92–23.61 USD) per year in donations. This study also revealed that the predicting factors influencing the respondents’ WTP for the promotion of the local forest ESs differed according to the financial resource type (taxes and donations). The results of this study are meaningful in that they can be used as empirical basic data in estimating payments and preparing measures to secure financial resources when designing payments for the ecosystem services for the local forest.

Mapping the deforestation footprint of nations reveals growing threat to tropical forests

Deforestation, a significant threat to biodiversity, is accelerated by global demand for commodities. Although prior literature has linked deforestation to global supply chains, here we provide a fine-scale representation of spatial patterns of deforestation associated with international trade. Using remote sensing data and a multi-region input-output model, we quantify and map the spatiotemporal changes in global deforestation footprints over 15 years (2001-2015) at a 30-m resolution. We find that, while many developed countries, China and India have obtained net forest gains domestically, they have also increased the deforestation embodied in their imports, of which tropical forests are the most threatened biome. Consumption patterns of G7 countries drive an average loss of 3.9 trees per person per year. Some of the hotspots of deforestation embodied in international trade are also biodiversity hotspots, such as in Southeast Asia, Madagascar, Liberia, Central America and the Amazonian rainforest. Our results emphasize the need to reform zero-deforestation policies through strong transnational efforts and by improving supply chain transparency, public-private engagement and financial support for the tropics.

Using satellite imagery to understand and promote sustainable development

Accurate and comprehensive measurements of a range of sustainable development outcomes are fundamental inputs into both research and policy. We synthesize the growing literature that uses satellite imagery to understand these outcomes, with a focus on approaches that combine imagery with machine learning. We quantify the paucity of ground data on key human-related outcomes and the growing abundance and improving resolution (spatial, temporal, and spectral) of satellite imagery. We then review recent machine learning approaches to model-building in the context of scarce and noisy training data, highlighting how this noise often leads to incorrect assessment of model performance. We quantify recent model performance across multiple sustainable development domains, discuss research and policy applications, explore constraints to future progress, and highlight research directions for the field.

Science based public policies: Lessons from Covid19 on the use of randomized trials

The current SARS-CoV-2 pandemic gave rise to a spirit of methodological anarchy in some fronts of biomedical research, embraced by some under the excuses of urgency and time restraints. This movement, however, comes at the same time when social sciences begin to recognize the value and soundness of the clinical research rationale - the need for randomization, of fair comparisons between intervention groups, the humility of acknowledging ignorance and accepting uncertainty, these last two imperatives usually subsumed under the principle of “equipoise”.

Topic evolution, disruption and resilience in early COVID-19 research

The COVID-19 pandemic presented a challenge to the global research community as scientists rushed to find solutions to the devastating crisis. Drawing expectations from resilience theory, this paper explores how the trajectory of and research community around the coronavirus research was affected by the COVID-19 pandemic. Characterizing epistemic clusters and pathways of knowledge through extracting terms featured in articles in early COVID-19 research, combined with evolutionary pathways and statistical analysis, the results reveal that the pandemic disrupted existing lines of coronavirus research to a large degree. While some communities of coronavirus research are similar pre- and during COVID-19, topics themselves change significantly and there is less cohesion amongst early COVID-19 research compared to that before the pandemic. We find that some lines of research revert to basic research pursued almost a decade earlier, whilst others pursue brand new trajectories. The epidemiology topic is the most resilient among the many subjects related to COVID-19 research. Chinese researchers in particular appear to be driving more novel research approaches in the early months of the pandemic. The findings raise questions about whether shifts are advantageous for global scientific progress, and whether the research community will return to the original equilibrium or reorganize into a different knowledge configuration.

What happens when the money runs out? Forest outcomes and equity concerns following Ecuador's suspension of conservation payments

Payments for Ecosystem Services (PES) are now a prominent policy instrument for conserving tropical forests. PES are voluntary, direct, and contractual: an ES buyer pays an ES steward for adopting conservation practices for a fixed term. A defining feature of PES is its 'quid pro quo' conditionality, e.g. stewards are paid only if they deliver contracted conservation outcomes. Most studies on PES effectiveness focus on the steward's compliance with contract conditions. By contrast, the buyer's compliance has received scant attention despite the fact that PES programs across the globe have delayed payments, suspended re-enrollment, or shut down altogether. 'Use-restricting' PES depend on the continued flow of funding to pay for conservation; however, institutional, political, and economic factors can disrupt or terminate PES funding. What happens when the PES money unexpectedly runs out? Do stewards continue to conserve or revert to their former practices? We use mixed methods to study equity concerns and forest outcomes of an unexpected, two-year interruption in conservation payments to 63 private landowners residing in Ecuador's Amazon and enrolled in the Socio Bosque program, compared to similar landowners who did not enroll. Using quasi-experimental methods, we found that during the payment suspension period enrolled properties did not maintain their conservation outcomes where deforestation pressures were high (e.g. close to roads). Where deforestation pressures were low, enrolled properties continued to conserve more, on average, than similar properties not enrolled. Findings from 40 interviews and 26 focus groups conducted before, during, and after the payment suspension exposed profound landowner uncertainty regarding their contract rights. Poor official communication and imbalanced PES contract terms reinforced power inequalities between the state and rural ES stewards. Our work highlights the need to plan for financial volatility and to protect participants' rights in PES contract design.

Forest-linked livelihoods in a globalized world

Forests have re-taken centre stage in global conversations about sustainability, climate and biodiversity. Here, we use a horizon scanning approach to identify five large-scale trends that are likely to have substantial medium- and long-term effects on forests and forest livelihoods: forest megadisturbances; changing rural demographics; the rise of the middle-class in low- and middle-income countries; increased availability, access and use of digital technologies; and large-scale infrastructure development. These trends represent human and environmental processes that are exceptionally large in geographical extent and magnitude, and difficult to reverse. They are creating new agricultural and urban frontiers, changing existing rural landscapes and practices, opening spaces for novel conservation priorities and facilitating an unprecedented development of monitoring and evaluation platforms that can be used by local communities, civil society organizations, governments and international donors. Understanding these larger-scale dynamics is key to support not only the critical role of forests in meeting livelihood aspirations locally, but also a range of other sustainability challenges more globally. We argue that a better understanding of these trends and the identification of levers for change requires that the research community not only continue to build on case studies that have dominated research efforts so far, but place a greater emphasis on causality and causal mechanisms, and generate a deeper understanding of how local, national and international geographical scales interact.

The Potential of Payment for Ecosystem Services for Crop Wild Relative Conservation

Crop wild relatives (CWR) have proven to be very valuable in agricultural breeding programs but remain a relatively under-utilized and under-protected resource. CWR have provided resistance to pests and diseases, abiotic stress tolerance, quality improvements and yield increases with the annual contribution of these traits to agriculture estimated at USD 115 billion globally and are considered to possess many valuable traits that have not yet been explored. The use of the genetic diversity found in CWR for breeding provides much-needed resilience to modern agricultural systems and has great potential to help sustainably increase agricultural production to feed a growing world population in the face of climate change and other stresses. A number of CWR taxa are at risk, however, necessitating coordinated local, national, regional and global efforts to preserve the genetic diversity of these plants through complementary in situ and ex situ conservation efforts. We discuss the absence of adequate institutional frameworks to incentivize CWR conservation services and propose payment for ecosystem services (PES) as an under-explored mechanism for financing these efforts. Such mechanisms could serve as a potentially powerful tool for enhancing the long-term protection of CWR.

Mechanisms and impacts of an incentive-based conservation program with evidence from a randomized control trial

Conservation science needs more high-quality impact evaluations, especially ones that explore mechanisms of success or failure. Randomized control trials (RCTs) provide particularly robust evidence of the effectiveness of interventions (although they have been criticized as reductionist and unable to provide insights into mechanisms), but there have been few such experiments investigating conservation at the landscape scale. We explored the impact of Watershared, an incentive-based conservation program in the Bolivian Andes, with one of the few RCTs of landscape-scale conservation in existence. There is strong interest in such incentive-based conservation approaches as some argue they can avoid negative social impacts sometimes associated with protected areas. We focused on social and environmental outcomes based on responses from a household survey in 129 communities randomly allocated to control or treatment (conducted both at the baseline in 2010 and repeated in 2015-2016). We controlled for incomplete program uptake by combining standard RCT analysis with matching methods and investigated mechanisms by exploring intermediate and ultimate outcomes according to the underlying theory of change. Previous analyses, focused on single biophysical outcomes, showed that over its first 5 years Watershared did not slow deforestation or improve water quality at the landscape scale. We found that Watershared influenced some outcomes measured using the survey, but the effects were complex, and some were unexpected. We thus demonstrated how RCTs can provide insights into the pathways of impact, as well as whether an intervention has impact. This paper, one of the first registered reports in conservation science, demonstrates how preregistration can help make complex research designs more transparent, avoid cherry picking, and reduce publication bias.

Overstated carbon emission reductions from voluntary REDD+ projects in the Brazilian Amazon

Reducing emissions from deforestation and forest degradation (REDD+) has gained international attention over the past decade, as manifested in both United Nations policy discussions and hundreds of voluntary projects launched to earn carbon-offset credits. There are ongoing discussions about whether and how projects should be integrated into national climate change mitigation efforts under the Paris Agreement. One consideration is whether these projects have generated additional impacts over and above national policies and other measures. To help inform these discussions, we compare the crediting baselines established ex-ante by voluntary REDD+ projects in the Brazilian Amazon to counterfactuals constructed ex-post based on the quasi-experimental synthetic control method. We find that the crediting baselines assume consistently higher deforestation than counterfactual forest loss in synthetic control sites. This gap is partially due to decreased deforestation in the Brazilian Amazon during the early implementation phase of the REDD+ projects considered here. This suggests that forest carbon finance must strike a balance between controlling conservation investment risk and ensuring the environmental integrity of carbon emission offsets. Relatedly, our results point to the need to better align project- and national-level carbon accounting.

Effective Conservation

Effective altruism is a growing humanitarian movement with a track record of success in evaluating the effectiveness of charitable spending across a wide range of projects. We suggest ways in which the foundations of this movement can be applied to the complex world of conservation.

Conditional cash transfers to alleviate poverty also reduced deforestation in Indonesia

Solutions to poverty and ecosystem degradation are often framed as conflicting. We ask whether Indonesia's national anti-poverty program, which transfers cash to hundreds of thousands of poor households, reduced deforestation as a side benefit. Although the program has no direct link to conservation, we estimate that it reduced tree cover loss in villages by 30% (95% confidence interval, 10 to 50%). About half of the avoided losses were in primary forests, and reductions were larger when participation density was higher. The economic value of the avoided carbon emissions alone compares favorably to program implementation costs. The program's environmental impact appears to be mediated through channels widely available in developing nations: consumption smoothing, whereby cash substitutes for deforestation as a form of insurance, and consumption substitution, whereby market-purchased goods substitute for deforestation-sourced goods. The results imply that anti-poverty programs targeted at the very poor can help achieve global environmental goals under certain conditions.

Formalizing land rights can reduce forest loss: Experimental evidence from Benin

Many countries are formalizing customary land rights systems with the aim of improving agricultural productivity and facilitating community forest management. This paper evaluates the impact on tree cover loss of the first randomized control trial of such a program. Around 70,000 landholdings were demarcated and registered in randomly chosen villages in Benin, a country with a high rate of deforestation driven by demand for agricultural land. We estimate that the program reduced the area of forest loss in treated villages, with no evidence of anticipatory deforestation or negative spillovers to other areas. Surveys indicate that possible mechanisms include an increase in tenure security and an improvement in the effectiveness of community forest management. Overall, our results suggest that formalizing customary land rights in rural areas can be an effective way to reduce forest loss while improving agricultural investments.

Does REDD+ have a chance? Implications from Pemba, Tanzania

Conservation scientists continue to debate the strengths and weaknesses of REDD+ as an instrument to slow greenhouse gas emissions in the developing world. We propose that general positions on this debate are less helpful than drawing lessons from specific investigations into the features of individual projects that make them successful or not. Here, focusing on a site-specific REDD+ intervention in Pemba, Zanzibar (Tanzania), we examine the circumstances under which REDD+ has a chance of success, teasing out specific features of both REDD+ interventions and the socio-economic and institutional contexts that render REDD+ a potentially valuable complement to community forestry. Additionally, we highlight some unanticipated positive outcomes associated with the design features of REDD+ projects. Our broader goal is to move away from ideologically-driven debate to empirically-based identification of general conditions where REDD+ could work, and to provide policy recommendations.

Vegetation Changes Attributable to Refugees in Africa Coincide with Agricultural Deforestation

The recent adoption of the Global Compact on Refugees formally recognizes not only the importance of supporting the nearly 26 million people who have sought asylum from conflict and persecution but also of easing the pressures on receiving areas and host countries. However, few countries may enforce the Compact out of concern over the economic or environmental repercussions of hosting refugees. We examine whether narratives of refugee-driven landscape change are empirically generalizable to continental Africa, which fosters 34% of all refugees. Estimates of the causal effects of the number of refugees-located in 493 camps distributed across 49 African countries-on vegetation from 2000 to 2016 are provided. Using a quasi-experimental design, we find refugees bear a small increase in vegetation condition while contributing to increased deforestation. Such a combination is mainly explained not by land clearance and massive biomass extraction but by agricultural expansion in refugee-hosting areas. A one percent increase in the number of refugees amplifies the transition from dominant forested areas to cropland by 1.4 percentage points. These findings suggest that changes in vegetation condition may ensue with the elevation of population-based constraints on food security.

Did Government Expenditure on the Grain for Green Project Help the Forest Carbon Sequestration Increase in Yunnan, China?

Reasonably assessing the effectiveness of government expenditure on the Grain for Green project (GFG) in providing forest carbon sequestration would contribute to the development of China’s forest carbon sequestration. Using the government expenditure data from the GFG in Yunnan Province from 2001 to 2015 and the MODIS Land Cover Type (MCD12Q1) time-series datasets, we calculated the forest carbon sequestration of various counties (cities or districts). The impacts of GFG government expenditure on forest carbon sequestration were empirically evaluated by the least squares dummy variables method (LSDV). The research results indicate that a 1% increase in government expenditure on the GFG yielded a 0.0364% increase in forest carbon sequestration. However, the effects of GFG government expenditure on forest carbon sequestration differed greatly in different areas because of the diversity of the natural environments, forest resource endowment, and government policies. If the initial forest endowment was not considered, the effectiveness of government expenditure on the GFG in providing forest carbon sequestration would have been overestimated. This study argues that, to improve the efficiency of GFG government expenditure in Yunnan Province, more investment should be made in regions with positive regression coefficients that have passed the significance t-test, such as Diqing Tibetan Autonomous Prefecture in the northwest, Baoshan City in the west, Honghe Hani and Yi Autonomous Prefecture in the south, and Wenshan Zhuang and Miao Autonomous Prefecture in the east.

National mitigation potential from natural climate solutions in the tropics

Better land stewardship is needed to achieve the Paris Agreement's temperature goal, particularly in the tropics, where greenhouse gas emissions from the destruction of ecosystems are largest, and where the potential for additional land carbon storage is greatest. As countries enhance their nationally determined contributions (NDCs) to the Paris Agreement, confusion persists about the potential contribution of better land stewardship to meeting the Agreement's goal to hold global warming below 2°C. We assess cost-effective tropical country-level potential of natural climate solutions (NCS)—protection, improved management and restoration of ecosystems—to deliver climate mitigation linked with sustainable development goals (SDGs). We identify groups of countries with distinctive NCS portfolios, and we explore factors (governance, financial capacity) influencing the feasibility of unlocking national NCS potential. Cost-effective tropical NCS offers globally significant climate mitigation in the coming decades (6.56 Pg CO₂e yr⁻¹ at less than 100 US$ per Mg CO₂e). In half of the tropical countries, cost-effective NCS could mitigate over half of national emissions. In more than a quarter of tropical countries, cost-effective NCS potential is greater than national emissions. We identify countries where, with international financing and political will, NCS can cost-effectively deliver the majority of enhanced NDCs while transforming national economies and contributing to SDGs.

This article is part of the theme issue ‘Climate change and ecosystems: threats, opportunities and solutions’.