Aligning natural climate solutions with mitigation policies for low-cost carbon neutrality: insights from the Qinghai–Tibet Plateau

Increasing concentrations of greenhouse gases (GHGs) are causing global climate change and decreasing the stability of the climate system. Long-term solutions to climate change will require reduction in GHG emissions as well as the removal of large quantities of GHGs from the atmosphere. Natural climate solutions (NCS), i.e., changes in land management, ecosystem restoration, and avoided conversion of habitats, have substantial potential to meet global and national greenhouse gas (GHG) reduction targets and contribute to the global drawdown of GHGs. However, the relative role of NCS to contribute to GHG reduction at subnational scales is not well known. We examined the potential for 12 NCS activities on natural and working lands in Oregon, USA to reduce GHG emissions in the context of the state’s climate mitigation goals. We evaluated three alternative scenarios wherein NCS implementation increased across the applicable private or public land base, depending on the activity, and estimated the annual GHG reduction in carbon dioxide equivalents (CO2e) attributable to NCS from 2020 to 2050. We found that NCS within Oregon could contribute annual GHG emission reductions of 2.7 to 8.3 MMT CO2e by 2035 and 2.9 to 9.8 MMT CO2e by 2050. Changes in forest-based activities including deferred timber harvest, riparian reforestation, and replanting after wildfires contributed most to potential GHG reductions (76 to 94% of the overall annual reductions), followed by changes to agricultural management through no-till, cover crops, and nitrogen management (3 to 15% of overall annual reductions). GHG reduction benefits are relatively high per unit area for avoided conversion of forests (125–400 MT CO2e ha-1). However, the existing land use policy in Oregon limits the current geographic extent of active conversion of natural lands and thus, avoided conversions results in modest overall potential GHG reduction benefits (i.e., less than 5% of the overall annual reductions). Tidal wetland restoration, which has high per unit area carbon sequestration benefits (8.8 MT CO2e ha-1 yr-1), also has limited possible geographic extent resulting in low potential (< 1%) of state-level GHG reduction contributions. However, co-benefits such as improved habitat and water quality delivered by restoration NCS pathways are substantial. Ultimately, reducing GHG emissions and increasing carbon sequestration to combat climate change will require actions across multiple sectors. We demonstrate that the adoption of alternative land management practices on working lands and avoided conversion and restoration of native habitats can achieve meaningful state-level GHG reductions.

Increasing concentrations of greenhouse gases (GHGs) are causing global climate change and decreasing the stability of the climate system. Long-term solutions to climate change will require reduction in GHG emissions as well as the removal of large quantities of GHGs from the atmosphere. Natural climate solutions (NCS), i.e., changes in land management, ecosystem restoration, and avoided conversion of habitats, have substantial potential to meet global and national greenhouse gas (GHG) reduction targets and contribute to the global drawdown of GHGs. However, the relative role of NCS to contribute to GHG reduction at subnational scales is not well known. We examined the potential for 12 NCS activities on natural and working lands in Oregon, USA to reduce GHG emissions in the context of the state's climate mitigation goals. We evaluated three alternative scenarios wherein NCS implementation increased across the applicable private or public land base, depending on the activity, and estimated the annual GHG reduction in carbon dioxide equivalents (CO2e) attributable to NCS from 2020 to 2050. We found that NCS within Oregon could contribute annual GHG emission reductions of 2.7 to 8.3 MMT CO2e by 2035 and 2.9 to 9.8 MMT CO2e by 2050. Changes in forest-based activities including deferred timber harvest, riparian reforestation, and replanting after wildfires contributed most to potential GHG reductions (76 to 94% of the overall annual reductions), followed by changes to agricultural management through no-till, cover crops, and nitrogen management (3 to 15% of overall annual reductions). GHG reduction benefits are relatively high per unit area for avoided conversion of forests (125-400 MT CO2e ha-1). However, the existing land use policy in Oregon limits the current geographic extent of active conversion of natural lands and thus, avoided conversions results in modest overall potential GHG reduction benefits (i.e., less than 5% of the overall annual reductions). Tidal wetland restoration, which has high per unit area carbon sequestration benefits (8.8 MT CO2e ha-1 yr-1), also has limited possible geographic extent resulting in low potential (< 1%) of state-level GHG reduction contributions. However, co-benefits such as improved habitat and water quality delivered by restoration NCS pathways are substantial. Ultimately, reducing GHG emissions and increasing carbon sequestration to combat climate change will require actions across multiple sectors. We demonstrate that the adoption of alternative land management practices on working lands and avoided conversion and restoration of native habitats can achieve meaningful state-level GHG reductions.

As the development of a green and low-carbon economy has received great attention from governments around the world, carbon peaking and carbon neutrality have become important issues raised by China. As a major energy consuming country, government has actively formulated and implemented various carbon emission reduction policies in order to curb carbon emissions. Whether these policies achieve economic growth in the process of energy conservation and emission reduction, and promote China’s green and low-carbon development transition is the focus of this paper. This paper selects data from 30 provinces in China from 2010 to 2019, establishes a model, and empirically analysis the impact of carbon emission reduction policy tools on economic growth. The results show that there is a significant negative correlation between mandatory carbon emission reduction policies and economic growth, while market-based carbon emission reduction policies enhance the economic strength of the region. In addition, this paper empirically tests that after the establishment of the carbon market in 2013, market-based carbon emission reduction policies have significantly promoted economic growth, and the impact of carbon emission reduction policies on economic growth have regional heterogeneity.

A framework for promoting natural climate solutions in the agriculture sector

Moving toward Net-Zero Emissions Requires New Alliances for Carbon Dioxide Removal

The protection, management and restoration of vegetated ecosystems on land and in the ocean (‘natural climate solutions’) can be a useful strategy for reducing net greenhouse gas emissions to help limit global warming. Their potential contribution to reducing net emissions has led to the development of policies and financial incentives for their protection and restoration. These have in turn created a set of expectations among some stakeholders, and interest in expanding these to encompass other ecosystems. However, there are specific rules about how abatement is calculated in international policy and climate finance, and the frameworks and terminology associated with them are often complex. This can be a barrier to stakeholders who want to leverage the potential of natural climate solutions, sometimes leading to incongruence between realised and anticipated benefits. In this article, we attempt to outline some of the key international policy and carbon market frameworks for coastal ‘blue carbon’ ecosystems, and the extent to which different ecosystems are accommodated. Currently, among the coastal ecosystems, only mangrove forests, seagrass meadows, and tidal marshes are typically considered in international policy and carbon market frameworks. The defining feature of these ecosystems is that the foundation species are plants that grow in sediment (soil). They are the only coastal ecosystems currently included in IPCC guidelines for national greenhouse gas inventories, and in compliance and voluntary carbon markets. There is interest in potentially including other marine ecosystems, such as kelp forests and unvegetated tidal flats, into carbon accounting frameworks, but there are unresolved questions about whether sequestration and storage of carbon by these ecosystems meets the rigorous standards required. Voluntary carbon markets have greater flexibility than mechanisms linked to national greenhouse gas inventories, and so might be early implementers of expanding methods to include other ecosystems. Incorporating coastal ecosystems into national greenhouse gas inventory is a useful action countries can take that will likely help generate incentives for protection and restoration of these important ecosystems.

Natural climate solutions (NCS) are recognized as an important tool for governments to reduce greenhouse gas emissions and remove atmospheric carbon dioxide. Using California as a globally relevant reference, we evaluate the magnitude of biological climate mitigation potential from NCS starting in 2020 under four climate change scenarios. By mid-century NCS implementation leads to a large increase in net carbon stored, flipping the state from a net source to a net sink in two scenarios. Forest and conservation land management strategies make up 85% of all NCS emissions reductions by 2050, with agricultural strategies accounting for the remaining 15%. The most severe climate change impacts on ecosystem carbon materialize in the latter half of the century with three scenarios resulting in California ecosystems becoming a net source of carbon emissions under a baseline trajectory. However, NCS provide a strong attenuating effect, reducing land carbon emissions 41–54% by 2100 with total costs of deployment of 752–777 million USD annually through 2050. Rapid implementation of a portfolio of NCS interventions provides long-term investment in protecting ecosystem carbon in the face of climate change driven disturbances. This open-source, spatially-explicit framework can help evaluate risks to NCS carbon storage stability, implementation costs, and overall mitigation potential for NCS at jurisdictional scales.

Environmental forcing and policy synergy: A multidimensional approach in the governance of air pollution and carbon emission

China is facing a huge challenge in achieving its carbon neutrality goal by 2060 given that it is currently one of the world’s largest greenhouse gas (GHG) emitters and has set a very short timeline for going from peak emissions to carbon neutrality. Natural climate solutions (NCS) that protect, manage, and restore ecosystems have shown substantial potential for increasing carbon sinks or reducing GHG emissions to offset fossil fuel CO2 emissions. This study quantified the mitigation potential of 18 NCS pathways in China at 0.67–1.65 Gigatonne of CO2 equivalent (Gt CO2e) yr−1 averaged from 2020 to 2060, which is even larger than the size of the current national terrestrial carbon sink. Compared with a previous global estimate, our results show a lower mitigation potential in forest ecosystems but a much greater potential for cropland ecosystems in China. From 2020 to 2060, all 18 pathways combined can provide cost-effective mitigation compared to the global social cost of CO2 emission and carbon prices, and 98.6% and 83.3% mitigation potential are cost-effective, respectively. This study further showed that immediate action provides the greatest mitigation. Our estimates highlight the important role of NCS in achieving the national carbon neutrality goal because of their large mitigation potential and cost-effectiveness.

Natural climate solutions can contribute to climate change mitigation and other environmental and social goals. An emerging body of academic and gray literature seeks to identify how governance ecosystems, inclusive of diverse actors, the mechanisms they employ, and the conditions they create, can actualize the potential of natural climate solutions. Enabling conditions are a critical component of these governance ecosystems as they describe the conditions needed to achieve a desired outcome. However, limited empirical research explores what conditions and combinations of conditions might promote the implementation of natural climate solutions across agricultural landscapes. This paper aims to identify and categorize enabling conditions for scaling natural climate solutions adoption in agriculture to address this gap. This objective is achieved through 51 semi-structured key informant interviews with diverse experts engaged in climate action in Canada's agriculture sector, which are corroborated with relevant literature. The expertise of key informants includes: agricultural production; agricultural technology; climate and environmental policy and markets; sustainable investment; sustainable sourcing and agri-food supply chains; measuring, reporting, and verification of ecosystem services; technical assistance; and ecosystem modeling. Findings from the interviews suggest that the potential for natural climate solutions adoption is currently limited by several critical barriers, including regulatory uncertainty, insufficient investment in measuring and monitoring infrastructure, and a lack of accessible and relevant resources to inform and guide actors. Aggregated findings point to four principal enabling conditions that together form the foundational conditions for an enabling governance ecosystem for natural climate solutions adoption in agriculture: (1) coordinated and coherent governance approaches; (2) favourable market conditions; (3) streamlined and robust measuring, reporting and verification; and (4) capacity among actors. This paper's contribution includes identifying and organizing enabling conditions for scaling the adoption of agriculture-based natural climate solutions, which can help better position actors to build an effective governance ecosystem in Canada's agriculture sector and elsewhere.

Natural climate solutions (NCS) could provide over one-third of the climate mitigation needed between now and 2030 to limit warming below 2°C and support the Sustainable Development Goals. However, large disparities persist between the estimated biophysical climate mitigation potential (CMP) of NCS and their actual implementation. Social, political, informational, and economic factors contribute to this gap, but the spatial distribution of these constraints and their impacts on different NCS pathways remains poorly understood. Understanding these constraints is especially important due to the large uncertainties in NCS CMP and growing research on spatial prioritization of NCS, often based only on biophysical criteria. We identified and mapped nonbiophysical constraints to NCS implementation efficacy by conducting a systematic review of recent peer-reviewed literature across 10 high-CMP NCS pathways. From 1,821 papers, we identified 352 that provided 2,480 observations of 39 unique constraints from 135 countries. We mapped the spatial distribution of these constraints and analyzed patterns across NCS pathways and geographic classifications. Lack of funding, insufficient information on NCS management, and ineffective policies emerged as the most common constraints globally. However, each pathway and geography faced a distinct suite of interrelated constraints spanning multiple categories. These findings highlight the need for context-specific, equitable solutions, likely requiring transdisciplinary approaches and cross-sectoral collaborations. The results could also help increase accuracy of NCS CMP estimates. We discuss how adaptive management may be used for NCS initiatives at any scale to proactively diagnose co-occurring constraints at each implementation phase and to develop integrated, place-based solutions.

Natural Climate Solutions (NCS) are climate mitigation approaches that aim to incorporate sustainable practices in forest, agriculture, wetland, and grassland management to increase GHG mitigation from land sectors and have been estimated to be highly effective from global to local scales. As more state and local governments seek to address climate change using a range of available techniques, the potential of NCS has gained increasing attention. As NCS directly involves land management by a range of actors (such as farmers and landowners) operating within resource-dependent communities (such as those dependent on the forest sector), it also has the potential to significantly alter the socioeconomic conditions and opportunities for these communities, necessitating a critical assessment of how NCS implementation interacts with socioeconomic systems. In this work, we focus on the implementation of NCS in Washington State to support its 2050 net-zero goals. Using a novel research approach, we compare recently estimated NCS potentials along multiple pathways with estimates of county-level socioeconomic sensitivities, exposures, and adaptive capacities to NCS-related changes and highlight the potential challenges that exist. These challenges can significantly limit the estimated GHG reduction and ecosystem co-benefits from NCS if they are implemented without due consideration of potential social interactions. We outline policies that can supplement NCS implementation to support just and equitable approaches that contribute to resilient communities and enhance human wellbeing while mitigating GHG emissions from the natural lands of Washington state.

Natural Climate Solutions (NCS) – protection, restoration, and improved management of lands and waters that reduce greenhouse gasses – have large climate change mitigation potential. However, a lack of comprehensive information on NCS implementation challenges hinders NCS adoption and delivery of near-term mitigation. Using a global survey of NCS projects and a systematic review of recent NCS studies, we map 46 constraints in eight categories, yielding 15,572 geo-referenced NCS pathway-constraint observations from 501 studies and projects in 137 countries covering 20 of 22 UN subregions. Social-behavioral, Knowledge, and Government-organizational are the most-reported constraint categories, and lack of policy coordination or implementation capacity the most-observed constraint and most frequently top-ranking constraint for pathways and subregions. Despite broad congruence, top constraint and category rankings vary among subregions and pathways, respectively. NCS projects generally encounter multiple constraints in multiple categories, indicating complex challenges. Without enabling efforts, near-term NCS mitigation may remain well below its biophysical potential.

Mitigating climate change requires clean energy and the removal of atmospheric carbon. Building soil carbon is an appealing way to increase carbon sinks and reduce emissions owing to the associated benefits to agriculture. However, the practical implementation of soil carbon climate strategies lags behind the potential, partly because we lack clarity around the magnitude of opportunity and how to capitalize on it. Here we quantify the role of soil carbon in natural (land-based) climate solutions and review some of the project design mechanisms available to tap into the potential. We show that soil carbon represents 25% of the potential of natural climate solutions (total potential, 23.8 Gt of CO2-equivalent per year), of which 40% is protection of existing soil carbon and 60% is rebuilding depleted stocks. Soil carbon comprises 9% of the mitigation potential of forests, 72% for wetlands and 47% for agriculture and grasslands. Soil carbon is important to land-based efforts to prevent carbon emissions, remove atmospheric carbon dioxide and deliver ecosystem services in addition to climate mitigation. Diverse strategies are needed to mitigate climate change. This study finds that storing carbon in soils represents 25% of land-based potential, of which 60% must come from rebuilding depleted carbon stores.

Eddy covariance measurement systems provide direct observation of the exchange of greenhouse gases between ecosystems and the atmosphere, but have only occasionally been intentionally applied to quantify the carbon dynamics associated with specific climate mitigation strategies. Natural climate solutions (NCS) harness the photosynthetic power of ecosystems to avoid emissions and remove atmospheric carbon dioxide (CO2), sequestering it in biological carbon pools. In this perspective, we aim to determine which kinds of NCS strategies are most suitable for ecosystem-scale flux measurements and how these measurements should be deployed for diverse NCS scales and goals. We find that ecosystem-scale flux measurements bring unique value when assessing NCS strategies characterized by inaccessible and hard-to-observe carbon pool changes, important non-CO2 greenhouse gas fluxes, the potential for biophysical impacts, or dynamic successional changes. We propose three deployment types for ecosystem-scale flux measurements at various NCS scales to constrain wide uncertainties and chart a workable path forward: "pilot", "upscale", and "monitor". Together, the integration of ecosystem-scale flux measurements by the NCS community and the prioritization of NCS measurements by the flux community, have the potential to improve accounting in ways that capture the net impacts, unintended feedbacks, and on-the-ground specifics of a wide range of emerging NCS strategies.