Carbon offsets from voluntary avoided-deforestation projects are generated on the basis of performance in relation to ex ante deforestation baselines. We examined the effects of 26 such project sites in six countries on three continents using synthetic control methods for causal inference. We found that most projects have not significantly reduced deforestation. For projects that did, reductions were substantially lower than claimed. This reflects differences between the project ex ante baselines and ex post counterfactuals according to observed deforestation in control areas. Methodologies used to construct deforestation baselines for carbon offset interventions need urgent revisions to correctly attribute reduced deforestation to the projects, thus maintaining both incentives for forest conservation and the integrity of global carbon accounting.
Reducing emissions from deforestation and forest degradation (REDD) projects are intended to decrease carbon emissions from forests to offset other carbon emissions and are often claimed as credits to be used in calculating carbon emission budgets. West et al. compared the actual effects of these projects with measurable baseline values and found that most of them have not reduced deforestation significantly, and those that did had benefits substantially lower than claimed (see the Perspective by Jones and Lewis). Thus, most REDD projects are less beneficial than is often claimed.
Conserving tropical forests is of utmost importance for the future of humanity and biodiversity. Changes in land use, mostly deforestation in the tropics, emit 5 billion metric tons of carbon dioxide annually—second only to fossil fuel use, which emits 35 billion tons (1). Reducing emissions to net zero is necessary to stabilize global temperatures (2). One controversial approach to tackle fossil-fuel emissions from private companies, individuals, and governments has been to “offset” them by investing in projects to either stop emissions that would have otherwise occurred, such as by reducing deforestation, or by investing in carbon uptake projects, such as forest restoration. On page 873 of this issue, West et al. (3) show that offsetting through paying projects to reduce emissions by conserving tropical forests is not reducing deforestation as claimed and is worsening climate change.
There is potential for nature-based solutions (NbS) to contribute to climate-resilient development (CRD) due to their integrated approach to mitigation, adaptation, and sustainable development. However, despite alignment between NbS and CRD’s objectives, realization of this potential is not guaranteed. A CRD pathways (CRDP) approach helps to analyze the complexities of the relationship between CRD and NbS, and a climate justice lens enables the identification of the multiple ways that NbS can support or undermine CRD by foregrounding the politics inherent in deciding between NbS trade-offs. We use stylized vignettes of potential NbS to examine how the dimensions of climate justice reveal the potential of NbS to contribute to CRDP. We consider tensions in NbS projects between local and global climate objectives, and the potential for NbS framing to reinforce inequalities or unsustainable practices. Ultimately, we present a framework that combines climate justice and CRDP in an analytical tool for understanding the potential for a NbS to support CRD in specific places.
The process of urbanization can alter the local climate to the point that it threatens citizens’ well-being by creating heat-related hazards. The construction of Blue-Green Infrastructure (BGI) can improve the regulation of surface energy exchange processes and address this problem. However, the time needed for a BGI to deliver a stable cooling performance, referred to here as the Cooling Establishment Time (CET), is poorly understood and quantified in the literature and dependent on environmental, design and maintenance factors. Here, we analyze the feasibility of using satellite data to derive the CET for different BGIs across the city of Zurich, Switzerland. Results showed that remote sensing can quantify the land surface temperature impact of BGIs and assist in estimating their CET. BGI with trees or climbing plants required a longer CET (seven to ten years) before any notable shift in surface temperatures were visible, while grasses or artificial irrigated systems led to shorter CETs (one to three years). These results allow us to better account for BGI cooling establishment when planning for areas that need urgent action under warming climates. This work supports evidence-based urban greenery planning and design towards cooling our increasingly warming cities in a timely manner.
The coming decades will define whether the
Amazon – home to more than 28 million inhabitants,
198 indigenous peoples, and harbouring the most
biodiverse forest, the largest freshwater reservoir
and the largest tropical bloc for climate regulation
on the planet – will become the great catalyst
for Brazil’s low-carbon economy. Or whether, in
the opposite direction, the Amazon will reach an
irreversible point of degradation, deepening current
inequalities and jeopardizing the stability and
competitiveness of the country’s entire economy.
How to guide the Legal Amazon towards a
decarbonization trajectory, transforming the region’s
economy so that it grows, generates opportunities,
values local cultures and environmental assets,
while fighting inequality and deforestation? This
question motivated the 76 researchers who signed
the New Economy for the Amazon report.
The study combines different techniques and
knowledge to present a unique depiction of the
Legal Amazon’s current economy, bringing to
light the region’s economic and environmental
relations with the rest of Brazil and the world.
The study focuses on carbon-intensive sectors
that must change course in order to become
a relevant part of a standing forest economy,
more suited to the challenges of this century.
The study further explores the role of the
bioeconomy, revealing a vigorous activity hitherto
invisible to conventional instruments used
to measure economic activity. Although it is
based on the secular form of production of the
original peoples, constantly innovated by local
technologies developed in Amazonian villages,
rural areas and cities, the bioeconomy remains
underestimated in terms of its current impact
and future potential. The work provides visibility
to these activities, demonstrating their relevance
as a solution for the region’s future economy.
The report also assesses the economic performance
of the Legal Amazon under different scenarios,
comparing the current trajectory, which has
been driving degradation, with alternative
decarbonization scenarios, especially in the
agricultural, livestock and energy sectors.
More than comparing GDP and job creation results,
as economic performance is traditionally assessed,
the New Economy for the Amazon gives shape to a
qualitative analysis of that which is wanted for the
future – and there is no future for Brazil without
the Amazon. The results show that it is impossible
for the country to reach its Paris Agreement
targets and contribute to curbing global warming
without eliminating deforestation in the Amazon.
Even assuming that deforestation is eliminated,
it will still be necessary to restore large areas of
the forest and adopt new ways of generating and
consuming energy, whether in rural or urban areas.
This report proposes a transition that generates
quality jobs and opportunities for the region’s
citizens, while driving important changes in the rest
of the country. The New Economy for the Amazon
can be the great catalyst for the decarbonization
of the entire Brazilian economy and the greatest
opportunity for economic and social development
in the country’s contemporary history.
Biodiversity offsetting is a globally influential policy mechanism for reconciling trade-offs between development and biodiversity loss. However, there is little robust evidence of its effectiveness. We evaluated the outcomes of a jurisdictional offsetting policy (Victoria, Australia). Offsets under Victoria’s Native Vegetation Framework (2002–2013) aimed to prevent loss and degradation of remnant vegetation, and generate gains in vegetation extent and quality. We categorised offsets into those with near-complete baseline woody vegetation cover (“avoided loss”, 2702 ha) and with incomplete cover (“regeneration”, 501 ha), and evaluated impacts on woody vegetation extent from 2008 to 2018. We used two approaches to estimate the counterfactual. First, we used statistical matching on biophysical covariates: a common approach in conservation impact evaluation, but which risks ignoring potentially important psychosocial confounders. Second, we compared changes in offsets with changes in sites that were not offsets for the study duration but were later enrolled as offsets, to partially account for self-selection bias (where landholders enrolling land may have shared characteristics affecting how they manage land). Matching on biophysical covariates, we estimated that regeneration offsets increased woody vegetation extent by 1.9%–3.6%/year more than non-offset sites (138–180 ha from 2008 to 2018) but this effect weakened with the second approach (0.3%–1.9%/year more than non-offset sites; 19–97 ha from 2008 to 2018) and disappeared when a single outlier land parcel was removed. Neither approach detected any impact of avoided loss offsets. We cannot conclusively demonstrate whether the policy goal of ‘net gain’ (NG) was achieved because of data limitations. However, given our evidence that the majority of increases in woody vegetation extent were not additional (would have happened without the scheme), a NG outcome seems unlikely. The results highlight the importance of considering self-selection bias in the design and evaluation of regulatory biodiversity offsetting policy, and the challenges of conducting robust impact evaluations of jurisdictional biodiversity offsetting policies.
The northern peatland carbon sink plays a vital role in climate regulation; however, the future of the carbon sink is uncertain, in part, due to the changing interactions of peatlands and wildfire. Here, we use empirical datasets from natural, degraded and restored peatlands in non-permafrost boreal and temperate regions to model net ecosystem exchange and methane fluxes, integrating peatland degradation status, wildfire combustion and post-fire dynamics. We find that wildfire processes reduced carbon uptake in pristine peatlands by 35% and further enhanced emissions from degraded peatlands by 10%. The current small net sink is vulnerable to the interactions of peatland degraded area, burn rate and peat burn severity. Climate change impacts accelerated carbon losses, where increased burn severity and burn rate reduced the carbon sink by 38% and 65%, respectively, by 2100. However, our study demonstrates the potential for active peatland restoration to buffer these impacts.
Nature-based solutions (NbS) have been gradually valued by various countries because they have great potential for contributing to the Paris Agreement goals and carbon neutrality and meanwhile render synergies in various dimensions. Currently, the evaluation of NbS policies in the Nationally Determined Contributions (NDCs) is still quite lacking. Based on the NDCs documents of 190 countries and the initial subcategories of related researches, this paper proposes a NbS analysis framework covering targets, pathways, policies, and synergies. Then examining the characteristics of NbS policies and actions of 190 Parties by ecosystems, including forests, farmlands, grasslands, coastal zones & wetlands, urban ecosystems, and other ecosystems with the framework. The results show that: 1) NbS has not yet become the mainstream measure worldwide to combat climate change while developing countries pay more attention to NbS than developed countries; 2) Current NbS targets set by 131 countries(about 69 %) are qualitative and 59 countries(about 31 %) for quantitative. There is no robust and accurate quantitative indicator system for NbS; 3) NbS pathways mentioned by 156 countries (about 82 %) are unevenly distributed in ecosystems and concentrated in forest and farmland ecosystems; 4) Just over a third of the 190 countries (about 35 %) don’t apply any NbS pathways with scientific foundations and only 27 parties (about 14 %) announce strengthening the related research of NbS pathways in supporting policies in the future. The scientific foundations of NbS are undervalued and more NbS pathways with reliable scientific foundations should be implemented; 5) A variety of policies, predominantly planning and law, have been adopted by 130 countries (about 68 %) to ensure NbS actions. Other types of policies still need to be further improved, covering financing, information system &research, and capacity building; 6) Funding needs are unclear and financing mechanisms are imperfect for NbS actions. Only about 1/6 of the countries have suggested estimated funding needs of NbS actions; 7) Only 18 countries (about 9.5 %) have recognized the synergistic benefits of NbS in economic, social, and environmental dimensions, and there are relatively limited methodologies for the assessment of NbS synergies. At last, suggestions are put forward to further promote NbS contributions to tackling climate change.
Old growth forests continue to decline.
Farmers are facing a volatile and uncertain future. From changes to the Common
Agriculture Policy, post Brexit, to the impacts of climate change and a nature crisis,
let alone the turbulent geopolitics affecting global food markets – all of these are
having a substantial impact on the farming operating context.
The introduction of ELMs in England and [their own sustainable land management
schemes] in Wales and Scotland and Northern Ireland is having far reaching
effects on many farmers’ balance sheets. The shift towards payments for
the provision and management of ‘public goods’ – those ecosystem services
that are not normally paid for in the marketplace – have the potential to make
a positive impact on the climate and nature crisis. But these environmental
land management schemes do not fill the gap left by CAP; and it is no surprise
therefore that farmers are now starting to look closely at the emerging
‘natural capital’ markets.
The role of nature restoration in mitigating the impacts of climate change is receiving increasing attention, yet the mitigation potential is often assessed in terms of carbon removal rather than the ability to meet temperature goals, such as those outlined in the Paris Agreement. Here, we estimate the global removal potential from nature restoration constrained by a “responsible development” framework and the contribution this would make to a 1.5°C temperature limit. Our constrained restoration options result in a median of 103 GtC (5%–95% range of −91 to 196 GtC) in cumulative removals between 2020 and 2100. When combined with deep-decarbonization scenarios, our restoration scenario briefly exceeds 1.5°C before declining to between 1.25°C and 1.5°C by 2100 (median, 50% probability). We conclude that additional carbon sequestration via nature restoration is unlikely to be done quickly enough to notably reduce the global peak temperatures expected in the next few decades. Land restoration is an important option for tackling climate change but cannot compensate for delays in reducing fossil fuel emissions.
Humanity is facing major social and ecological impacts from climate change and biodiversity loss. These two crises are intertwined, with common causes and effects on one another. Pörtner et al. review the results of a joint meeting of members of the International Panels on Climate Change and Biodiversity and Ecosystem Services. They discuss the connections between biodiversity loss and climate change and propose potential solutions for addressing them as interconnected problems. Drastic reductions in greenhouse gas emissions, protection of multiuse landscapes and seascapes, and policies for providing equitable access to natural resources can help to ensure future ecological function and human well-being. —BEL
Despite worldwide prevalence, post-agricultural landscapes remain one of the least constrained human-induced land carbon sinks. To appraise their role in rebuilding the planet’s natural carbon stocks through ecosystem restoration, we need to better understand their spatial and temporal legacies.
In provisioning human civilization with food, fuel, and fiber for millennia, agriculture has drastically depleted terrestrial carbon stocks at the expense of natural ecosystems. Our challenge today is to use more sustainable practices to recapture some of the 116 Pg of soil organic carbon (SOC) lost since agriculture began, while simultaneously ensuring global food security1,2. That being said, the cessation of agriculture altogether is still the most efficient way to increase carbon stocks and restore ecosystems in tandem and at large scales.
Consider the vast expanses of forests that regrew over the 60 Mha of cropland abandoned following the collapse of the Soviet Union3. It has been called the world’s largest human-made carbon sink attributed to a single event;4 a title challenged by the climatic consequences of the ‘Great Dying in the Americas’ and its 56 Mha abandoned following the arrival of Europeans5. At more practical scales, intentional efforts to restore agricultural land such as the Grain-for-Green program in China and the Conservation Reserve Program in the USA have demonstrated that carbon sequestration is far from being the only advantage6,7. Ecological co-benefits include reduced soil erosion and water run-off, reduced flooding and drought, and improved soil health, water quality, and biodiversity indicators.
These post-agricultural landscapes (PALs) often signify the return of ecosystem properties, such as carbon, towards pre-disturbance states or new equilibria through secondary succession. Whether planned or unplanned, they appear in every agricultural region of the world and they can drawdown carbon with or without human involvement. If commitments to halt gross forest area loss by 2030 succeed, recarbonizing PALs will play a key role in reversing global land use change from being a net carbon source to a net sink8.
Unfortunately, PALs are insufficiently represented in terrestrial carbon models, both spatially (as a poorly mapped land cover class) and temporally (as uncertain carbon sinks). This hinders our ability to monitor, quantify, and leverage them strategically. We discuss here some of the reasons behind these issues and what can be done to address them so that we can properly evaluate the role of PALs.
Trait evolution is shaped by carbon economics at the organismal level. Here, we expand this idea to the ecosystem level and show how the trait diversity of ecological communities influences the carbon cycle. Systematic shifts in trait diversity will likely trigger changes in the carbon cycle.
Natural climate solutions are being advanced to arrest climate warming by protecting and enhancing carbon capture and storage in plants, soils and sediments in ecosystems. These solutions are viewed as having the ancillary benefit of protecting habitats and landscapes to conserve animal species diversity. However, this reasoning undervalues the role animals play in controlling the carbon cycle. We present scientific evidence showing that protecting and restoring wild animals and their functional roles can enhance natural carbon capture and storage. We call for new thinking that includes the restoration and conservation of wild animals and their ecosystem roles as a key component of natural climate solutions that can enhance the ability to prevent climate warming beyond 1.5 °C.
Nature-based solutions (NBS) are widely regarded as cost-effective responses to climate change and environmental degradation that also provide numerous co-benefits. However, despite significant policy attention, NBS plans often fail to materialize due to public budget shortfalls. Alongside traditional public finance, the international debate increasingly urges the mobilization of private capital for NBS through alternative financing (AF) techniques. In this scoping review, we examine the literature on a) the AF models connected to NBS and b) the drivers and barriers associated with these AF models in terms of their financial technicity and their embeddedness in the political, economic, social, technological, legal/institutional, and environmental/spatial (“PESTLE”) context. Although many models are discussed, the results indicate that none can be considered full substitutes for traditional public finance. Barriers and drivers converge around seven overarching tensions: new revenue and risk distribution vs. uncertainty, budgetary and legal pressure vs. political willingness and risk aversion, market demand vs. market failures, private sector engagement vs. social acceptance and risks, legal and institutional conduciveness vs. inertia, and upscaling potential vs. environmental risks and land use. Future research should focus on a) how to further integrate NBS monitoring, quantification, valuation, and monetization into AF models, b) systemic and empirical approaches to improve the understanding of the applicability and transferability of AF models, and c) an exploration of the potential qualities and social risks of AF models in NBS governance arrangements.
A confluence of concerns about tropical forest loss, global warming, and social inequality drive calls to transform land use governance. Yet there is widespread debate about what must be transformed, by whom, and how. The increasing equation of transformation with ambitious, quantitative global targets, such as “net zero emissions” or “zero deforestation” has gained widespread appeal as a means to inspire action and hold powerful actors to account. However presenting targets themselves as the end goals of transformation, obscures both the means of achieving them and the social and environmental values that legitimate them. The escalation of targets for land use, in particular, is disconnected from targeted geographies, lacks accountability to socially diverse knowledge and priorities, and is readily appropriated by powerful actors at multiple scales. This paper argues instead, for an equity-based approach to transformation that reveals how unequal power distorts both the ends and the means of global governance. We illustrate this argument with five case-study “vignettes” in Indonesia, Ghana, Peru, and Brazil that reveal how de-contextualized, target-based thinking has reinforced state and corporate control over resources at the expense of local access, while largely failing to deliver the promised environmental outcomes. We conclude that equity-focused, case study research is critical not only to unpack the local consequences of pursuing global targets, but also to make visible alternative efforts to achieve deeper socio-environmental transformations.
The Brazilian Atlantic Forest (BAF) is a global biodiversity hotspot, but its carbon sink capacity, especially in the subtropical portion, is poorly understood. We aimed to evaluate the relationship between biodiversity measures (i.e., taxonomic, functional, and phylogenetic diversity) and net carbon change across subtropical BAF, testing whether there is a win–win situation in the conservation of biodiversity and carbon sink capacity across forests of distinct ages. We obtained the net carbon change from 55 permanent plots, from early successional to old-growth forests, by combining the carbon gains and losses across two censuses. We found that subtropical BAF are on average acting as a carbon sink, but carbon gains and losses varied a lot across plots, especially within late successional/old-growth forests. The carbon sink was consistent across different forest ages, and we did not find a relationship between biodiversity and net carbon change in subtropical BAF. Therefore, conservation programs should aim at both targets in order to maximize the protection of biodiversity and carbon capture across the secondary and old-growth subtropical BAF, especially in a scenario of global changes.
The globally important carbon sink of intact, old-growth tropical humid forests is declining because of climate change, deforestation and degradation from fire and logging1,2,3. 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 Africa5,6. On the basis of satellite data products4,7, 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.
Humankind faces a Triple Challenge: averting dangerous climate change, reversing biodiversity loss, and supporting the wellbeing of a growing population. Action to address each of these issues is inherently dependent on action to address the others. Local, national, and international policy goals on climate change, biological diversity, and human wellbeing have been set. Current implementation measures are insufficient to meet these goals, but the Triple Challenge can still be met if governments, corporations, and other stakeholders take a holistic perspective on management of land and waters. To inform this effort, we identify a set of priority policy responses drawn from recent international assessments that, whilst not being the only potential solutions, can form the core of such a holistic approach. We do this through an iterative process using three methodological approaches: (i) structured literature review; (ii) deliberative expert analysis; and (iii) wider consultation, before synthesizing into this paper. Context-appropriate implementation of responses will be needed to capitalize on potential policy synergies and to ensure that unavoidable trade-offs between management of land and waters for climate mitigation, biodiversity restoration, and human wellbeing outcomes are made explicit. We also set out four approaches to managing trade-offs that can promote fair and just transitions: (1) social and economic policy pivoting towards ‘inclusive wealth’; (2) more integrated policymaking across the three areas; (3) ‘Triple Challenge dialogues’ among state and non-state actors; and (4) a new research portfolio to underpin (1), (2), and (3).
Wildlife conservation in Africa has been dominated by protected areas (PAs) that largely excluded the interests of local communities. While this “fortress conservation” has succeeded in securing natural habitat and wildlife populations, it has come at a cost to local communities who forego access to natural resources on which their livelihoods depend and who obtain few direct benefits from the designated PAs. Concomitantly, climate change poses formidable challenges that require urgent attention to meet global climate goals. Combining finance mechanisms primarily intended for climate outcomes with community-based conservation models presents opportunities to integrate nature conservation and climate change mitigation and adaptation while providing direct income to local communities. In this chapter, we present an example of a results-based system of payments for ecosystem services – the purchase of verified emission reductions for use as carbon offsets. We outline the key steps for planning and implementing the REDD+ project of Makame Wildlife Management Area, and emphasize the monitoring of key parameters associated with climate, community and wildlife benefits. Our case study depicts an innovative, nature-based solution to climate change, wildlife conservation, and rural livelihoods for an African savannah rangeland where conventional approaches are insufficient to meet the costs of conservation.
Transformation towards low carbon development needs action to transform our economy and energy simultaneously. India has taken several noble aims for continuing to increase renewable energy since an efficient energy transition will help to mitigate climate change. Socio-economic consequences like a considerable loss of livelihood will also occur. The ‘just transition’ concept emphasises delivering the transition fairly to high carbon concentrated workers’ communities’ livelihood and fossil fuel-based economy towards the regenerative economy and addressing inequality and poverty issues. While nature-based solutions are initiatives taken to restore, protect, and sustainably manage nature to tackle societal problems such as changing climate, challenges originating from urban expansion and livelihood support. There is a substantial research gap on why efforts to address just transition should support nature-based solutions (NbS). This research paper tries to offer a detailed perspective regarding the possibilities of delivering just transition and relate it to nature-based solutions based on available literature and various examples worldwide.
During the past century, semi-natural grasslands, once widespread throughout Europe, have largely been converted into intensively managed agricultural areas, abandoned or afforested. These large-scale land-use changes have already resulted in considerable biodiversity loss but can also lead to decline in ecosystem service provision and ecosystem multifunctionality. We assessed the impact of afforestation and abandonment of semi-natural grasslands on the supply of ecosystem services in Western Estonia. We compared a wide array of services provided by open grasslands, abandoned grasslands, and afforested grasslands. Additionally, we analysed the impact of land-use change and species richness on ecosystem multifunctionality. Significant declines in the supply of pollination services, natural pest regulation, forage production, soil quality, wild food and cultural appreciation of landscape were detected as a result of overgrowing or afforestation. There was significant positive relationship between species richness and ecosystem multifunctionality, i.e. more biodiverse grasslands were able to support more services at higher capacity. Results show that both grassland degradation due to abandonment, as well as grassland afforestation, have significant negative impacts on biodiversity, on the supply of multiple important ecosystem services and on the ecosystem multifunctionality. Synthesis and applications. Temperate semi-natural grasslands have high biodiversity and capacity to deliver multiple important ecosystem services simultaneously. Conservation and restoration of grassland habitats must be considered as an important part of sustainable landscape planning.
Climate-related benefits of afforestation depend on the balance of the often-contrasting effects of biogeochemical (carbon sequestration) and biogeophysical (radiation balance) effects. These effects are known to vary at the continental scale (e.g., from boreal to tropical regions). Here, we show in a four-year study that the biogeochemical vs. biogeophysical balance in paired forested and non-forested ecosystems across short distances (approximately 200 Km) and steep aridity gradient (aridity index 0.64 to 0.18) can change dramatically. The required time for the forestation cooling effects via carbon sequestration, to surpass warming effects associated with the forests’ reduced albedo and suppressed longwave radiation, decreased from 213 years in the driest sites to 73 years in the intermediate and 43 years in the wettest sites. Climate-related benefits of forestation, previously considered at large-spatial scales, should be considered at high-spatial resolutions in climate-change mitigation programs aimed at taking advantage of the vast non-forested dry regions.
Marine protected areas (MPAs) are increasingly being promoted as an ocean-based climate solution. However, such claims remain controversial because of the diffuse and poorly synthesized literature on climate benefits of MPAs. To address this knowledge gap, we conducted a systematic literature review of 22,403 publications spanning 241 MPAs and analyzed these across 16 ecological and social pathways through which MPAs could contribute to climate change mitigation and adaptation. Our meta-analysis demonstrates that marine conservation can significantly enhance carbon sequestration, coastal protection, biodiversity, and the reproductive capacity of marine organisms as well as fishers’ catch and income. Most of these benefits are only achieved in fully or highly protected areas and increase with MPA age. Although MPAs alone cannot offset all climate change impacts, they are a useful tool for climate change mitigation and adaptation of social-ecological systems.
