Natural Climate Solutions Research Articles

Ecological restoration enhances dryland carbon stock by reducing surface soil carbon loss due to wind erosion

Enhancing terrestrial carbon (C) stock through ecological restoration, one of the prominent approaches for natural climate solutions, is conventionally considered to be achieved through an ecological pathway, i.e., increased plant C uptake. By conducting a comprehensive regional survey of 4279 1 × 1 m2 plots at 517 sites across China's drylands and a 13-y manipulative experiment in a semiarid grassland within the same region, we show that greater soil and ecosystem C stocks in restored than degraded lands result predominantly from decreased surface soil C loss via suppressed wind erosion. This biophysical pathway is always overlooked in model evaluation of land-based C mitigation strategies. Surprisingly, stimulated plant growth plays a minor role in regulating C stocks under ecological restoration. In addition, the overall enhancement of C stocks in the restored lands increases with both initial degradation intensity and restoration duration. At the national scale, the rate of soil C accumulation (7.87 Tg C y-1) due to reduced wind erosion and surface soil C loss under dryland restoration is equal to 38.8% of afforestation and 56.2% of forest protection in China. Incorporating this unique but largely missed biophysical C-conserving mechanism into land surface models will greatly improve global assessments of the potential of land restoration for mitigating climate change.

Technical note: Comparison of radiometric techniques for estimating recent organic carbon sequestration rates in inland wetland soils

Abstract. For wetlands to serve as natural climate solutions, accurate estimates of organic carbon (OC) sequestration rates in wetland sediments are needed. Dating using cesium-137 (137Cs) and lead-210 (210Pb) radioisotopes is commonly used for measuring OC sequestration rates in wetland sediments. 137Cs radioisotope dating is relatively simple, with calculations based on a single point representing the onset (1954) or peak (1963) of the 137Cs fallout. 210Pb radioisotope dating is more complex, as the calculations are based on multiple points. Here, we show that reliable dating of sediment cores collected from wetlands can be achieved using either 137Cs or 210Pb dating or their combination. However, 137Cs and 210Pb profiles along the depth of sediment cores need to be screened, analyzed, and interpreted carefully to estimate OC sequestration rates with high precision. To this end, we propose a decision framework for screening 137Cs and 210Pb profiles into high- and low-quality sediment profiles, and we compare dating using the 1954 and 1963 time markers, i.e., the rates of sedimentation and, consequently, OC sequestration over the past ∼ 60 years. Our findings suggest that 137Cs- and 210Pb-based OC sequestration rates are comparable, especially when using the 1963 (vs. 1954) time marker.

Climate mitigation potential of natural climate solutions and clean energy on The Nature Conservancy properties in California, USA.

Natural climate solutions (NCS) and transitioning to clean energy can reduce greenhouse gases and contribute to mitigating climate change. Private landowners with large holdings, such as conservation organizations like The Nature Conservancy, have set ambitious goals to reduce net emissions and increase sequestration on their lands by implementing NCS. We assessed the potential carbon dioxide-equivalent (CO2e) reduction from feasible NCS, specifically implementing new restoration and agricultural management activities, and transitions to clean energy on The Nature Conservancy, California chapter's fee-owned and conservation easement properties. We compared the total CO2e reduction from potential new NCS activities to the impact from ongoing NCS activities, the chapter's 2030 goal, and the state's reduction goal for natural and working lands to understand how the organization can contribute to climate mitigation. We found that implementing NCS on 37 fee-owned properties (63,175 MTCO2e year -1) and clean energy on 10 fee-owned properties (488 MTCO2e year -1) combined would not reach the chapter's 2030 goal (72,000 MTCO2e year -1), and there can be tradeoffs between maximizing CO2e reduction and protecting conservation values. However, ongoing changes to forest management on a single conservation easement property, where another non-profit harvests timber and sells carbon credits, currently contributes 147,749 MTCO2e year -1, more than two times the 2030 goal and representing 7.4% of the state's annual goal. Our results suggest that The Nature Conservancy, California chapter would need to implement NCS on some of the conservation easements or consider future land protection deals with carbon rich ecosystems or high impact NCS to reach their CO2e reduction goal.

Climate feedback from plant physiological responses to increasing atmospheric CO2 in Earth system models.

Plant physiological responses to increasing atmospheric CO2 concentration (iCO2), including enhanced photosynthesis and reduced stomatal conductance, impact regional and global climate. Here, I describe recent advances in understanding these effects through Earth system models (ESMs). Idealized simulations of a 1% annual iCO2 show that despite fertilization, CO2 physiological forcing contributes to 10% of warming and at least 30% of future precipitation decline in Amazonia. This reduces aboveground vegetation carbon storage and triggers positive carbon-climate feedback. ESM simulations indicate that reduced transpiration and increased heat stress from iCO2 could amplify meteorological drought and wildfire risks. Understanding these climate feedbacks is essential for improving carbon accounting in natural climate solutions, such as avoiding deforestation and reforestation, as iCO2 complicates assessing their climate benefits.

Co‐benefits of and trade‐offs between natural climate solutions and Sustainable Development Goals

Co‐benefits of and trade‐offs between natural climate solutions and Sustainable Development Goals

The Impact of Drought on Terrestrial Carbon in the West African Sahel: Implications for Natural Climate Solutions

AbstractTerrestrial ecosystems store more than twice the carbon of the atmosphere, and are critical to climate change mitigation efforts. This has led to a proliferation of land‐based carbon sequestration efforts, such as re/afforestation associated with the Great Green Wall in the West African Sahel (WAS GGW). However, we currently lack comprehensive assessments of the long‐term viability of these ecosystems' carbon storage in the context of increasingly severe climate extremes. The WAS is particularly prone to recurrent and disruptive extremes, exemplified by the persistent and severe late‐20th century drought. We assessed the response and recovery of WAS GGW carbon stocks and fluxes to this late‐20th century drought, and the subsequent rainfall recovery, by leveraging a suite of terrestrial ecosystem models. While multi‐model mean carbon fluxes (e.g., gross primary production, respiration) partly recovered to pre‐drought levels, modeled total (above and below ground) ecosystem carbon stock falls to as much as two standard deviations below pre‐drought levels and does not recover even ∼20 years after the maximum drought anomaly. Furthermore, to the extent that the modeled regional carbon stock recovers, it is nearly entirely driven by atmospheric CO2 trends rather than the precipitation recovery. Uncertainties in regional ecosystem carbon simulation are high, as the models' carbon responses to drought displayed a nearly 10‐standard deviation spread. Nevertheless, the multi‐model average response highlights the strong and persistent impact of drought on terrestrial carbon storage, and the potential risks of relying on terrestrial ecosystems as a “natural climate solution” for climate change mitigation.

Peat profile database from peatlands in Canada.

Peatlands cover approximately 12% of the Canadian landscape and play an important role in the carbon cycle through their centennial- to millennial-scale storage of carbon under waterlogged and anoxic conditions. In recognizing the potential of these ecosystems as natural climate solutions and therefore the need to include them in national greenhouse gas inventories, the Canadian Model for Peatlands module (CaMP v. 2.0) was developed by the Canadian Forest Service. Model parameterization included compiling peat profiles across Canada to calibrate peat decomposition rates from different peatland types, to define typical bulk density profiles, and to describe the hydrological (i.e., water table) response of peatlands to climatic changes. A total of 1217 sites were included in the dataset from published and unpublished sources. The CORESITES table contains site location and summary data for each profile, as well as an estimate of total carbon mass per unit area (in megagrams of C per hectare). Total carbon mass per unit area at each location was calculated using bulk density and carbon content through each profile. The PROFILES table contains data for depth (in centimeters), bulk density (in grams per cubic meter), ash and carbon content (in percentage), and material descriptions for contiguous samples through each peat profile. Data gaps for bulk density and C content were filled using interpolation, regression trees, and assigned values based on material description and/or soil classification to allow for the estimation of total carbon mass per unit area. A subset of the sites (N = 374) also have pH and pore water trace-elemental geochemistry data and are found in the WATER table. The REFERENCES table contains the full citation of each source of the data and is linked to each core location through the SOURCEDATA table. The LOOKUP table defines codes in the database that required more space that what was sufficient in the metadata tables. The data can be accessed on Open Government Canada and will be useful for future work on carbon stock mapping and ecosystem modeling. All metadata and data are provided © Her Majesty the Queen in Right of Canada, 2023 and information contained in this publication may be reproduced for personal or public noncommercial purposes with attribution, whereas commercial reproduction and distribution are prohibited except with written permission from NRCan; complete details are noted in the Supporting Information file Metadata S1 (see Class III.B.3: Copyright restrictions).

New perspectives on temperate inland wetlands as natural climate solutions under different CO2-equivalent metrics

There is debate about the use of wetlands as natural climate solutions due to their ability to act as a “double-edged sword” with respect to climate impacts by both sequestering CO2 while emitting CH4. Here, we used a process-based greenhouse gas (GHG) perturbation model to simulate wetland radiative forcing and temperature change associated with wetland state conversion over 500 years based on empirical carbon flux measurements, and CO2-equivalent (CO2-e.q.) metrics to assess the net flux of GHGs from wetlands on a comparable basis. Three CO2-e.q. metrics were used to describe the relative radiative impact of CO2 and CH4—the conventional global warming potential (GWP) that looks at pulse GHG emissions over a fixed timeframe, the sustained-flux GWP (SGWP) that looks at sustained GHG emissions over a fixed timeframe, and GWP* that explicitly accounts for changes in the radiative forcing of CH4 over time (initially more potent but then diminishing after about a decade)—against model-derived mean temperature profiles. GWP* most closely estimated the mean temperature profiles associated with net wetland GHG emissions. Using the GWP*, intact wetlands serve as net CO2-e.q. carbon sinks and deliver net cooling effects on the climate. Prioritizing the conservation of intact wetlands is a cost-effective approach with immediate climate benefits that align with the Paris Agreement and the Intergovernmental Panel on Climate Change timeline of net-zero GHG emissions by 2050. Restoration of wetlands also has immediate climate benefits (reduced warming), but with the majority of climate benefits (cooling) occurring over longer timescales, making it an effective short and long-term natural climate solution with additional co-benefits.

Mapping forest-based natural climate solutions

Natural climate solutions are critical actions of ecosystem stewardship to mitigate climate change. However, prioritizing locations and possible actions is challenging. We demonstrate a generalizable approach for identifying potential opportunities for natural climate solutions by creating a spatial hierarchy of land management restrictions. Global forest carbon stocks and flux models were then used to explore forest-based natural climate solutions in the high-carbon density coastal temperate rainforests of western North America. Our results show 13 million hectares are available for action, an area that holds 4,900 ± 640 megatonnes of carbon dioxide equivalent and represents 45% of regional and 0.5% of global aboveground forest carbon stocks. Based on historical trends, a 10% reduction in average annual forest carbon loss through improved forest management and conservation could reduce forest carbon emissions by 9.1 megatonnes of carbon dioxide equivalent per year, corresponding to 5.2% of the 2030 land-based climate commitments made by the United States and Canada. Large-scale implementation of natural climate solutions will require collaborative planning with forest-dependent communities, industry, governments, and Indigenous peoples.

Seas the opportunity: multi-criteria decision analysis to identify and prioritise blue carbon wetland restoration sites

IntroductionThe emergence of voluntary carbon markets is creating new opportunities to sustainably finance Natural Climate Solution (NCS) projects. In Australia, the federal government recently enacted the Tidal Restoration of Blue Carbon Ecosystems Methodology Determination 2022 (Tidal Reconnection Method), whereby restoration activities that reintroduce tidal flows to allow the re-establishment of coastal wetland (blue carbon) ecosystems, through the removal or modification of a tidal restriction, can be used to gain and sell Australian carbon credit units. Australia has the highest net blue carbon wealth in the world, with 5%–11% of global carbon stocks, yet there is currently a lack of large-scale feasibility assessments and supporting methodologies to identify and prioritise sites with the greatest potential for NCS project implementation to help inform investment decisions.MethodsIn this study, we applied a spatial Multi-Criteria Decision Analysis (MCDA) to identify, map, and prioritise potential sites for blue carbon coastal wetland restoration in South Australia that meet criteria outlined in the Tidal Reconnection Method. This study compared information on 1) predicted flooding extent following tidal reconnection and under sea level rise (SLR; present-day, 2050 and 2,100); 2) project implementation complexity (e.g. who possesses land tenure); and 3) carbon sequestration potential through predicted area of vegetation change under the above SLR scenarios. ResultsOur results identified 64 sites of interest, of which 32 received an overall “high” prioritisation score of 3 or more out of 5. This equates to approximately 21,114 ha of high priority potential blue carbon restoration sites.DiscussionThe MCDA enables development of a portfolio of viable restoration projects through a rapid “desktop” prioritisation of sites of interest, which can then guide investment in further detailed cost/benefit feasibility assessments. This study demonstrates an adaptable MCDA approach to map potential NCS projects at meaningful spatial scales and in-line with carbon market-based opportunities.

Strong climate mitigation potential of rewetting oil palm plantations on tropical peatlands

For decades, tropical peatlands in Indonesia have been deforested and converted to other land uses, mainly oil palm plantations which now cover one-fourth of the degraded peatland area. Given that the capacity for peatland ecosystems to store carbon depends largely on hydrology, there is a growing interest in rewetting degraded peatlands to shift them back to a carbon sink. Recent estimates suggest that peatland rewetting may contribute up to 13 % of Indonesia's total mitigation potential from natural climate solutions. In this study, we measured CO2 and CH4 fluxes, soil temperature, and water table level (WTL) for drained oil palm plantations, rewetted oil palm plantations, and secondary forests located in the Mempawah and Kubu Raya Regencies of West Kalimantan, Indonesia. We found that peatland rewetting significantly reduced peat CO2 emissions, though CH4 uptake was not significantly different in rewetted peatland compared to drained peatland. Rewetting drained peatlands on oil palm plantations reduced heterotrophic respiration by 34 % and total respiration by 20 %. Our results suggest that rewetting drained oil palm plantations will not achieve low CO2 emissions as observed in secondary forests due to differences in vegetation or land management. However, extrapolating our results to the areas of degraded oil palm plantations in West Kalimantan suggests that successful peatland rewetting could still reduce emissions by 3.9 MtCO2 yr−1. This result confirms that rewetting oil palm plantations in tropical peatlands is an effective natural climate solution for achieving national emission reduction targets.

Global conservation priorities of coastal habitats towards extreme sea level rise risks

Approximately 70% of the world's largest megacities (>10 million people) are within 60 km of the coast, contributing to 50% of the world's GDP. Sea level rise will intensify coastal flood threats, making cities without sufficient habitat protection even more vulnerable. However, there is currently a lack of thorough evaluation at the global scale about conservation priorities based on the current habitat cover and the high sea level rise in order to adapt coastal flood risks. Here we assessed the disparity among habitat coverage, exposed population and extreme sea level rise to identify priority areas for future coastal conservation. These priority areas are characterized by a large population residing in low-elevation coastal zones (LECZs), high extreme sea levels (ESLs), and insufficient habitat coverages. In many highly populated countries like China and India, the flooding risk has been underestimated due to insufficient adaptation based on natural processes from coastal habitats. These highly populated countries are especially concerning because they have comparatively less vegetation protection capability and are subjected to high ESLs. Globally, Asian and European nations, such as China, Japan, Bangladesh, Viet Nam, the United Kingdom, Belgium, Ireland, the Netherlands, and Germany, have the highest potential for mitigating coastal risks through natural habitat conservation and restoration. We found that the main contributors to variations in the extreme sea level rise risks are not due to exposure headcounts (6%), but due to inadequate habitat cover (42%), which can be improved through targeted conservation and restoration. Our research identified the global priorities for managing climate resilience that most urgently require ecosystem conservation and restoration in order to prepare for the risks of coastal flooding.

Assessing the impact of afforestation as a natural climate solution in the Canadian boreal

Assessing the impact of afforestation as a natural climate solution in the Canadian boreal

Maximizing tree carbon in croplands and grazing lands while sustaining yields

BackgroundIntegrating trees into agricultural landscapes can provide climate mitigation and improves soil fertility, biodiversity habitat, water quality, water flow, and human health, but these benefits must be achieved without reducing agriculture yields. Prior estimates of carbon dioxide (CO2) removal potential from increasing tree cover in agriculture assumed a moderate level of woody biomass can be integrated without reducing agricultural production. Instead, we used a Delphi expert elicitation to estimate maximum tree covers for 53 regional cropping and grazing system categories while safeguarding agricultural yields. Comparing these values to baselines and applying spatially explicit tree carbon accumulation rates, we develop global maps of the additional CO2 removal potential of Tree Cover in Agriculture. We present here the first global spatially explicit datasets calibrated to regional grazing and croplands, estimating opportunities to increase tree cover without reducing yields, therefore avoiding a major cost barrier to restoration: the opportunity cost of CO2 removal at the expense of agriculture yields.ResultsThe global estimated maximum technical CO2 removal potential is split between croplands (1.86 PgCO2 yr− 1) and grazing lands (1.45 PgCO2 yr− 1), with large variances. Tropical/subtropical biomes account for 54% of cropland (2.82 MgCO2 ha− 1 yr− 1, SD = 0.45) and 73% of grazing land potential (1.54 MgCO2 ha− 1 yr− 1, SD = 0.47). Potentials seem to be driven by two characteristics: the opportunity for increase in tree cover and bioclimatic factors affecting CO2 removal rates.ConclusionsWe find that increasing tree cover in 2.6 billion hectares of agricultural landscapes may remove up to 3.3 billion tons of CO2 per year – more than the global annual emissions from cars. These Natural Climate Solutions could achieve the Bonn Challenge and add 793 million trees to agricultural landscapes. This is significant for global climate mitigation efforts because it represents a large, relatively inexpensive, additional CO2 removal opportunity that works within agricultural landscapes and has low economic and social barriers to rapid global scaling. There is an urgent need for policy and incentive systems to encourage the adoption of these practices.

Assessing the potential of large-scale urban forest projects as a natural climate solution

Urban forests are considered a nature-based solution for climate change by cities and countries worldwide. However, the effectiveness of large-scale urban forest projects as a natural climate solution has been rarely assessed. In this study, we utilized a unique opportunity from Beijing's actions to implement a large urban forest project since 2012 to examine the effectiveness of the proposed solution. We collected vegetation structure data in two extensive field surveys to track the growth of the newly formed urban forest. Using field data and allometric equations, we estimated carbon sequestrated by the urban forest. We found that between 2013 and 2020, the urban forest grew rapidly, with the average increase of DBH and height reaching 0.95 cm and 0.47 m annually, respectively. The 16,667 ha of trees and shrubs sequestrated 423,074 tons of carbon in ten years, or 42,307 tons annually. The result showed that large-scale urban forest projects have the potential to be used as a natural climate solution (NCS). Nevertheless, planning and developing specific management techniques are needed to fully realize this potential.

Pastures as natural climate solutions: A socioecological study of tree carbon and beef production trade-offs

Sustainable management strategies that facilitate the incorporation of trees into cattle pastures are widely recognized as emerging natural climate solutions. However, their potential to dually improve ecological functioning and human livelihoods has yet to be evaluated across regions on local scales, utilizing both ecological and sociological data. Further, the relationship between landowner participation in conservation management programs (CMPS) and their management priorities (i.e. production vs sustainability) also remains unclear. Therefore, the aims of this study were to evaluate the accuracy of past global-scale remote estimations of aboveground biomass and derived tree carbon density (MgC ha−1) within pasturelands at the local scale in both temperate and tropical regions. We also sought to analyze how participation in CMPs related to the perceptions of stakeholders toward the ecological health of their system. We compared findings between farms in temperate (n = 26) and tropical (n = 16) ecosystems. We found that discrepancies exist between previous remote studies and current field estimations of tree carbon in the farms, and these differences were not regionally uniform. In contrast, stakeholders enrolled in CMPs had a higher value of trees in both regions. CMPs participants also had lower annual stocking rates than those that practiced conventional management but no differences in woody species diversity (H’) or tree carbon (MgC ha−1). We demonstrate the urgent need for local-scale studies to accurately estimate tree carbon in mosaic pasture systems and the importance of conservation management in shifting the priorities of landowners, which could eventually lead to more sustainable systems.

Merging adoption of natural climate solutions in agriculture with climatic and non-climatic risks within an (intra)gendered framework.

The extant research on climate variability shares significant theoretical contributions to vulnerability and risks. However, the literature mostly focuses on technical solutions to climate extremes which undermines efforts to identify and solve the dynamics within gender groups in using agricultural-based natural climate solutions (NCS) to address climatic and non-climatic risks. With this in mind, this study implements both quantitative and qualitative approaches including household surveys, key informant interviews, and focus group discussions to investigate the adoption of NCS within gender groups to address climatic and non-climatic risks in three selected communities (Katanga, Dakio, and Zonno) in the Bolgatanga East District of Upper East Region of Ghana. The Relative Importance Index (RII) was used to rank the key climatic and non-climatic risks confronting smallholder farmers in the district. Male and female smallholder farmers affirmed that there has been variation in the climate compared to their childhood. The results indicated climate change-induced erosion (RII = 0.268) as the highest climatic risk among male smallholder farmers. Increased bushfire (RII = 0.263) was the highest climatic risk affecting female smallholder farmers. The findings show that the high cost of farm inputs (RII = 0.505) is the highest non-climatic risk among the male smallholder farmers whereas inadequate credit facilities (RII = 0.295) affected most of the female smallholder farmers. In adapting to the climatic risks, both male and female smallholder farmers with no formal education plant early maturing crop varieties and cover crops on their farmland. Others engage in traditional non-farm activities such as weaving by using renewable materials with reduced ecological footprints to address non-climatic risks. The male and female smallholder farmers with post-secondary education typically resort to temporal migration during the dry season to work on non-farm jobs. Acknowledging the intra-gendered adoption of NCS among marginalized farming households; not only protects against maladaptation but also improves local-level resilience and climate risk management in Ghana.

Quantifying the fluxes of carbon loss from an undrained tropical peatland ecosystem in Indonesia

Conservation of undrained tropical peatland ecosystems is critical for climate change mitigation as they store a tremendous amount of soil carbon that is preserved under anoxic water-logged conditions. Unfortunately, there are too few measurements of carbon fluxes from these ecosystems to estimate the climate change mitigation potential from such conservation efforts. Here, we measured carbon dioxide (CO2) and methane (CH4) fluxes as well as fluvial organic carbon export over the peat swamp forest within an undrained tropical peatland landscape in East Kalimantan, Indonesia. Our measurements throughout one year (Oct 2022–Sep 2023) showed that despite its water-logged condition, peat and water overlying the swamp forest on average emits 11.02 ± 0.49 MgCO2 ha−1 yr−1 of CO2 and 0.58 ± 0.04 MgCO2e ha−1 yr−1 of CH4. Further, the fluvial organic carbon export contributes to additional carbon loss of 1.68 ± 0.06 MgCO2e ha−1 yr−1. Our results help improve the accuracy of carbon accounting from undrained tropical peatlands, where we estimated a total carbon loss of 13.28 ± 0.50 MgCO2e ha−1 yr−1. Nevertheless, the total carbon loss reported from our sites is about half than what is reported from the drained peatland landscapes in the region and resulted in a larger onsite carbon sink potential estimate compared to other undrained peat swamp forests. Together, these findings indicate that conserving the remaining undrained peatland ecosystems in Indonesia from drainage and degradation is a promising natural climate solution strategy that avoids significant carbon emissions.

Severe decline in large farmland trees in India over the past decade

Agroforestry practices that include the integration of multifunctional trees within agricultural lands can generate multiple socioecological benefits, in addition to being a natural climate solution due to the associated carbon sequestration potential. Such agroforestry trees represent a vital part of India’s landscapes. However, despite their importance, a current lack of robust monitoring mechanisms has contributed to an insufficient grasp of their distribution in relation to management practices, as well as their vulnerability to climate change and diseases. Here we map 0.6 billion farmland trees, excluding block plantations, in India and track them over the past decade. We show that around 11 ± 2% of the large trees (about 96 m2 crown size) mapped in 2010/2011 had disappeared by 2018. Moreover, during the period 2018–2022, more than 5 million large farmland trees (about 67 m2 crown size) have vanished, due partly to altered cultivation practices, where trees within fields are perceived as detrimental to crop yields. These observations are particularly unsettling given the current emphasis on agroforestry as a pivotal natural climate solution, playing a crucial role in both climate change adaptation and mitigation strategies, in addition to being important for supporting agricultural livelihoods and improving biodiversity.

Climate mitigation potential and economic costs of natural climate solutions for main cropping systems across China

CONTEXTNatural climate solutions (NCS) offer immediate and cost-effective ways to tackle the climate crisis by transforming atmospheric carbon to soil carbon or avoiding greenhouse gas emissions. However, the climate mitigation potential and economic costs of NCS for cropping systems in China remain inconclusive. OBJECTIVEThe major objectives of this study are (i) to estimate the NGHG reduction potential across Chinese main cropping systems caused by NCS, (ii) to quantify the economic costs of adopting optimal management with different abatement potentials. METHODSThe Denitrification-Decomposition (DNDC) model was used to estimate the NGHG, including SOC sequestration, N2O emissions, and CH4 emissions. After calibration, we ran the DNDC model with derived data at municipality-level. We estimated the NGHG under current management, adopting optimal management individually, and integrated optimal management to project the maximum NGHG reduction potential caused by NCS. We used the marginal abatement cost method to estimate the economic cost. RESULTS AND CONCLUSIONSThe four natural climate solutions, N fertilization management (NFM), straw returning management (SRM), tillage management (TM), and rice irrigation management (RIM) can reduce national NGHG in main cropping systems by approximately 118.8 Tg CO2-eq, 116.3 Tg CO2-eq, 35.2 Tg CO2-eq, and 74.4 Tg CO2-eq, respectively. The integrated optimal management may potentially reduce NGHG by 256.9 Tg CO2-eq, equivalent to 90.2% of current NGHG, and 80% of which can be realized at the price of CN¥ 285 (Mg CO2-eq)−1. We further identify the priority NCS for different crops and regions and conclude that nitrogen fertilization management should be the priority NCS at the national level. SIGNIFICANCEOur findings highlight the great potential of NGHG reduction by adopting NCS precisely and the importance of optimizing agricultural management as a whole, and they will help policy makers to develop smart-agriculture in China.