Land cover changes (LCCs) influence land surface temperature through biogeophysical (BGP) and biogeochemical (BGC) processes. Yet, their combined, spatially varying effects remain inadequately quantified for major LCCs in China over the past two decades. This study integrates biogeophysical and biogeochemical processes to assess how LCCs affect local land surface temperature (LST) across China from 2000 to 2020, leveraging satellite-derived LST data and transient climate response estimates from CMIP5 models. We find that LCCs occurred in 5.87% of China’s land area, driven by ecological restoration, cropland expansion, and urbanization. These LCCs caused a BGP warming of 0.000181°C nationally, which was counteracted by a BGC cooling of -0.000199°C (a magnitude equivalent to 110% of the BGP warming) associated with a net carbon sink of 1.33 GtCO 2 . The resulting combined net cooling effects indicate that LCCs overall played a mitigating role against background warming. Regionally, the combined effects showed strong warming in eastern China, linked to urbanization and cropland degradation, and cooling in western China, driven by ecological restoration. BGC effects dominated the local LST response over BGP effects in most (80%) LCC areas except urbanization. Local synergy between BGP and BGC was observed in 61% of LCC areas, where they intensify each other’s local effects. These findings reveal distinct synergistic and tradeoff relationships between BGP and BGC effects associated with LCCs and their spatial patterns. It also highlights the potential of effective land use/cover management as a natural climate solution for climate mitigation.

Atmospheric nitrogen deposition and increased precipitation are key drivers of grassland carbon cycling; however, their long-term interactive effects and mechanisms remain poorly understood. Based on a 20 year field experiment with sustained nitrogen (10 g N m-2 yr-1) and precipitation (+∼50% precipitation) addition in a temperate grassland in northern China, we found that both nitrogen deposition and precipitation addition significantly enhanced net ecosystem CO2 exchange (NEE), ecosystem respiration (ER), and gross ecosystem productivity (GEP), with additive effects of nitrogen and water addition on NEE and GEP. Structural equation modeling revealed that nitrogen deposition increased carbon fluxes by enhancing community-weighted mean leaf area (CWMLA) and chlorophyll content of dominant species, whereas precipitation addition stimulated carbon fluxes mainly through improving soil moisture (SM) and CWMLA. Notably, nitrogen deposition and precipitation addition enhanced GEP to a greater extent than ER, which led to a net ecosystem carbon sink and exhibited a significant interaction effect exclusively on ER. These findings underscore previously underexplored mechanisms linking plant trait and SM dynamics to carbon flux responses. Our results indicate that long-term increases in nitrogen deposition and precipitation may accelerate carbon cycling in temperate grasslands and enhance the carbon sequestration function of grasslands. Our study provides unique long-term evidence to demonstrate that nitrogen and precipitation additions exert progressively stronger positive effects on grassland carbon fluxes over time, providing critical insights for predicting ecosystem responses to sustained climate change and informing adaptive nitrogen and SM management strategies.

ABSTRACT Soil organic carbon stocks (SOCS) play a critical role in mitigating atmospheric CO2 and enhancing ecosystem resilience, yet their controls in high-mountain environments remain insufficiently constrained. Using an integrated framework combining field sampling, remote sensing, machine learning, and multi-source environmental datasets, this study quantifies SOCS variability along elevation gradients across the climatically diverse region of Gilgit-Baltistan, northern Pakistan. Results reveal three dominant patterns. First, SOCS distribution is jointly regulated by elevation and climate, with humid mid-to-high altitudes functioning as net carbon sinks, whereas lower-elevation semi-humid and semi-arid regions exhibit persistent SOCS declines. This spatial–altitudinal coupling highlights the sensitivity of mountain SOCS to aridity across both vertical and horizontal landscapes. Second, climatic drivers exert contrasting effects: precipitation enhances SOCS accumulation in humid zones by promoting vegetation productivity, while rising temperatures in semi-humid and semi-arid belts accelerate carbon losses through enhanced decomposition. Third, vegetation–soil interactions amplify sequestration potential along elevation gradients. Grasslands developed on loamy soils at mid-to-high elevations store significantly higher SOCS than other land use–soil combinations, while carbon stocks decline sharply with soil depth, reflecting the vertical constraints imposed by shallow mountain soils. Together, these findings demonstrate that SOCS dynamics in fragile high-mountain ecosystems emerge from the interaction of elevation, climate variability, vegetation cover, and soil properties. Recognizing this multidimensional control is essential for designing zone-specific management strategies that enhance carbon sequestration, reduce vulnerability to climate change, and support regional contributions to global climate mitigation and sustainable development goals.

The Middle Jurassic represents a typical greenhouse climate period in Earth’s history, during which global carbon cycle perturbations and climatic events left significant records in continental strata. This study investigates the extremely thick coal seam of the Middle Jurassic Xishanyao Formation in the Wucaiwan mining area, Zhundong coalfield, Xinjiang, China. Through integrated coal petrological, geochemical, palynological, and organic geochemical analyses, combined with paleowildfire indicators, it aims to reconstruct the paleoenvironmental and paleoclimatic evolution sequence and explore its response to global changes. The results demonstrate that geochemical indicators and palynological assemblages collectively indicate an aridification trend in the paleoclimate. The high inertinite content and enrichment of combustion-derived polycyclic aromatic hydrocarbons in the coal attest to frequent medium-to low-temperature surface paleowildfire events during peat accumulation. On geological timescales, wildfires acted as a significant short-term carbon source, releasing vast amounts of greenhouse gases; however, over the long term, they ultimately functioned as a net carbon sink through the production of inert black carbon, facilitation of vegetation succession, and enhancement of organic matter burial. The Middle Jurassic paleoenvironmental evolution in the Junggar Basin exhibits synchronicity with global climate events, underscoring the key driving role of wildfire activity in the greenhouse Earth’s carbon cycle.

Variations in terrestrial carbon flux influence atmospheric CO2 exchange and related climate feedback, with Net ecosystem productivity (NEP) serving as a key metric for assessing ecosystem carbon source–sink dynamics. Given the vital ecological barrier function of the Tibetan Plateau (TP), understanding the spatiotemporal variability of NEP and its climatic controls is essential for elucidating carbon sink and climate interactions under ongoing climate change. The spatiotemporal dynamics of NEP across the TP from 1979 to 2018 are investigated using the process-based Community Land Model version 5.0 (CLM5.0). And climate sensitivity experiments are conducted to quantify the relative contributions of different climate factors to NEP variability. Furthermore, future changes in NEP for the period 2025–2100 under multiple Shared Socioeconomic Pathway (SSP) scenarios are projected. The results indicate that the TP functioned predominantly as a net carbon sink during the historical period, with a multi-year mean NEP of 23.96 g C m2 yr−1. Spatially, NEP showed a significantly increasing gradient from the northwest to the southeast. During 1979–2018, NEP exhibited an overall decreasing trend across most regions of the TP. Air temperature was identified as the dominant controlling factor, accounting for approximately 68% of the interannual NEP variability, followed by solar radiation (21%) and precipitation (11%). The dominant climatic drivers of NEP variation differ among regions: air temperature predominates in the southwestern and southeastern regions, radiation dominates in the northwestern and central areas, and precipitation exerts a controlling effect in the northern and western regions. Future projections suggest that NEP remains positive under all SSP scenarios, indicating that the TP is likely to persist as a carbon sink throughout the 21st century. This study provides important reference for the development of ecological protection, restoration planning, and regional carbon neutrality strategies.

Emission reduction and remittance enhancement in the agricultural sector are crucial to achieving the dual-carbon goal. Taking the Jiangsu Coastal Economic Belt (JCEB) as the research object, the carbon emission coefficient method and the parameter estimation method are adopted to measure the total carbon emission, carbon sink, and net carbon sink (NCS) of the 20 districts and counties from 2005 to 2023 in JCEB. On this basis, the study further analyzes spatial-temporal characteristics and dynamic evolution trends. The spatio-temporal geographically weighted regression model (GTWR) is used to explore the spatio-temporal heterogeneity and evolutionary pattern of each influencing factor. The results showed that: ① The agricultural NCS (measured by C) in JCEB decreased from 3.12×106 t in 2005 to 1.32×106 t in 2023, showing an overall trend of fluctuating decline. Spatially, the total NCS showed a distribution pattern of "high in the center and low in the north and south, " with most areas being low-carbon surplus areas. ② Among the influencing factors, the intensity of financial support for agriculture (FSA), the grain to economy crop ratio (GER), and agricultural development levels (ADL) had positive driving effects on the agricultural NCS. The positive effects of the first two factors continued to strengthen, while the contribution of the latter showed a "U"-shaped change trend. Fertilizer application intensity (FAI), agricultural machinery use intensity (AMI), and rural residents' income level (RRI) generally inhibited the growth of the agricultural NCS. The inhibitory effects of the first two factors were declining, while the negative effect of the latter decreased with economic growth. ③ The impact direction and intensity of each driving factor on the agricultural NCS in different counties showed significant differences. The impact effects of FSA and FAI were distinctly different in the north and south. The impact effects of GER and ADL showed agglomeration characteristics at the municipal level. In contrast, the influence intensity of AMI and RRI on the agricultural NCS presented an overall pattern of interlaced distribution in the north and south.

Medicinal and aromatic plants (MAPs) represent high-value agricultural commodities that provide economic returns through essential oil production while potentially contributing to climate change mitigation via photosynthetic carbon sequestration and oxygen release. Despite their recognized economic importance, few studies have systematically quantified the net environmental performance of MAP cultivation and processing within integrated climate mitigation frameworks. This study evaluated the carbon footprint, oxygen production, and CO₂ absorption of two commercially important MAPs—Pelargonium graveolens (geranium) and Viola odorata (violet)—cultivated under Egyptian field conditions, using life cycle assessment methodology with system boundaries from field operations through extraction. Primary data were collected from commercial farms (geranium: 37 feddans aggregated; violet: 1 feddan) over complete growing cycles. Geranium (6-month season) demonstrated net climate-positive performance with a negative carbon footprint of − 375 kg CO₂-eq. per feddan per season, producing 54,324 m³ of oxygen and absorbing 155,632 kg CO₂ during growth, with photosynthetic uptake exceeding all process emissions (fuel, irrigation electricity, fertilizers, and composting). In contrast, violet (12-month annual cycle) exhibited a positive footprint of + 15,972 kg CO₂-eq. per feddan annually, despite generating 11,148 m³ oxygen and absorbing 12,700 kg CO₂, primarily due to its fuel-intensive solvent extraction process that accounts for 97.3% of total emissions. Monte Carlo uncertainty analysis (N = 10,000 simulations) confirmed geranium’s robustness as a net carbon sink (probability 67.4%) while violet remained a consistent carbon source under current extraction practices. Scenario modeling demonstrated that substituting fossil fuel with solar thermal energy or biogas-derived heat for violet distillation could reduce net emissions by 50–100%, potentially shifting the crop from carbon source to near-neutral status. These findings indicate that MAPs can function as climate-smart crops when cultivation practices are coupled with renewable energy integration in post-harvest processing. The study provides quantitative evidence for prioritizing low-emission extraction technologies and precision irrigation management in MAP value chains to maximize both economic and environmental sustainability outcomes.

The municipal solid waste management sector is a nationally significant greenhouse gas source in Sri Lanka, yet decision makers lack comprehensive, city-level life-cycle assessment of full waste management chains. This study quantifies and compares greenhouse gas emissions and mitigation potential of alternative waste management scenarios for Colombo and Kandy, supporting nationally determined contributions (NDC) 3.0. Using IPCC 2021 GWP100 V1.03 as the impact assessment method, six scenarios were assessed, including business-as-usual, recycling, composting, confined cover windrow composting, anaerobic digestion, refuse-derived fuel production, incineration, pyrolysis, co-processing in cement kilns, open dumping, and sanitary landfilling. The business-as-usual scenario, dominated by open dumping, resulted in the highest greenhouse gas emissions in both Colombo and Kandy. In contrast, the integrated waste management approach (Scenario 3), combining anaerobic digestion, confined cover windrow composting, refuse-derived fuel production, and enhanced recycling, converted both cities from net emitters to net carbon sinks. Over the projection period of 2026–2035, this transition is expected to deliver substantial cumulative emission reductions, contributing significantly toward achieving NDC 3.0 waste sector targets in Sri Lanka despite the relatively small share of national baseline emissions in the sector. These findings highlight the strong mitigation potential of integrated waste management systems for advancing low-carbon urban strategies.

Abstract Large earthquakes in mountainous regions trigger extensive landslides, which mobilize organic carbon via soil erosion and vegetation loss, disrupting carbon reservoirs and influencing CO 2 levels. Quantifying earthquake impacts on carbon stock and cycling remains challenging. Here, we use field organic carbon data from 91 quadrats and over 20 years of remote sensing imagery to assess the impact of landslides from the 2008 M w 7.9 Wenchuan earthquake on the carbon budget. We show that these landslides removed 2.72 ± 0.52 Tg of organic carbon in the upper Min Jiang. While its oxidation releases CO 2 , rapid revegetation offsets this, making the earthquake a net carbon sink. Time-series data indicate that vegetation carbon stocks will recover to 50% of pre-earthquake levels in 74 ± 5 years, whereas soil organic carbon recovery to 50% may take 500–850 years. This study highlights the decadal to centennial-scale impact of extreme events on carbon cycling.

Vegetation plays a dual role in the Earth's climate system: it removes atmospheric CO2 through photosynthesis while emitting biogenic volatile organic compounds (BVOCs), which can weaken the net carbon sink and contribute to air pollution. To assess the long-term interplay between carbon uptake and BVOC emissions, and to clarify how vegetation characteristics and climate regulate this relationship, we developed a Biogenic Carbon Efficiency Index (BCEI). The BCEI integrates BVOC emissions with gross primary productivity (GPP) to quantify their spatial ratio, thereby capturing the concurrent "source" and "sink" attributes of vegetation. We characterize the spatiotemporal heterogeneity of the BCEI across China and identify its dominant environmental drivers. The BCEI decreases from southeast to northwest, and during 2001-2020 exhibited a declining trend over 78% of the country, with increases mainly in Southwest China and on the Shandong and Liaodong Peninsulas. Driver analyses indicate that variables linked to hydrothermal conditions, including temperature, precipitation, evapotranspiration, and soil moisture, primarily control BCEI variability. Across most regions, the BCEI is negatively correlated with soil moisture and precipitation, positively correlated with evapotranspiration, and shows regionally varying associations with temperature. These findings deepen understanding of vegetation's dual role as a source and sink and its driving mechanisms, providing a theoretical basis for optimizing regional vegetation management strategies.

ABSTRACTWetlands are the largest natural source of methane, yet their desiccation releases substantial amounts of carbon dioxide. Changing wetland emissions provide the greatest source of uncertainty in global emissions estimates due to limited data for key tropical carbon sources and sinks, including the Congo Basin. Here we quantified changing swamp forest hydrology, forest productivity and greenhouse gas emissions between 2007 and 2024 using satellite Earth observation and emissions datasets. We show that swamp forests expanded from 195,345 km2 to 222,467 km2 between 2007 and 2024, demonstrating a reversal of previously reported long‐term drying trends. The observed wetting trend increased productivity in both swamp and terra firme forests. Despite increasing methane emissions, wetland expansion reduced CO2‐equivalent emissions by 2 (95% CI; −2.94 to −1.12) million tonnes per year since 2007, highlighting the region's increasing role as a net carbon sink and its significance for global carbon budgets.

Lake expansion enhances inorganic and organic carbon sinks in sediments of lake Qinghai, Tibetan Plateau.

Sequestering carbon in forest ecosystems is an important nature-based solution for mitigating climate change. One way to assess the effectiveness of carbon uptakes in forestry is to determine the effect that the inclusion of carbon price has on the length of economic rotation period of forest stands. Whether and until when forests should be left unharvested and store carbon in living biomass and deadwood, or harvested and store carbon in harvested wood products is the issue, which is investigated in this study by computing rotation ages that consider both commercial timber and carbon prices. The optimization is carried out with an economic-ecological model that includes size-structured matrix growth model and accounts for climate effects on forest dynamics. The study concerns with uneven-aged mixed-species forests consisting of Norway spruce (Picea abies L.), European beech (Fagus sylvatica L.) and silver fir (Abies alba Mill.). The data on forest initial distributions comes from the Czech National Forest Inventory. The results showed that inclusion of carbon pricing to economic criteria for determining optimal rotation ages prolongs the rotation period. An increase in the carbon prices postpones optimal harvest age and leads to higher total net carbon sinks. However, the optimal solutions are sensitive not only to the discount rate, but also to the growth conditions of forest site and future climate evolution.

Abstract. The global land carbon sink has increased since the pre-industrial period, driven by the increasing atmospheric CO2 concentration and physical processes influenced by climate change. However, detecting these anthropogenic signals in the global land carbon sink is challenging due to the large year-to-year variability, which can mask or amplify long-term trends, particularly on regional and decadal scales. This study aims to detect the time it takes for long-term trends driven mostly by anthropogenic signal to dominate over natural variations, that is, the “time of emergence”, in the land carbon sink. For this, we use five large ensembles of historical simulations (1851–2014) and future scenarios (2016–2100) from Earth system models (ESMs). Our results show that, firstly, the anthropogenic signal in the global net land carbon sink emerges from 26 to 66 years in the period 1960–2009 (relative to the natural variations in the period of 1930–1959), depending on the ESM considered. The time of emergence is considerably shorter for the two major gross carbon fluxes: 8–13 years for gross primary productivity and 6–10 years for total ecosystem respiration. Furthermore, we find that long-term trends in the net land carbon sink at most regional scales take at least 20 years longer to emerge than at the global scale, due to the larger contributions from internal climate variability at smaller scales. Secondly, future scenarios show delayed signal detection compared to historical trends. This delay is mainly due to weaker anthropogenic signal trends rather than stronger natural variability. The weaker signal reflects primarily the slow-down of the increasing net land carbon sink in response to emission mitigation. Thirdly, we apply dynamical adjustment to filter out the year-to-year circulation-induced variability in both the historical and future simulations. This approach substantially shortens the detection time for the global net land carbon sink: between 34 %–39 % for the historical period and 29 %–55 % for the future simulations. This approach can also shorten the detection time for observational based datasets (30 % reduction in the period 1960–2009), thereby improving our ability to detect long-term trends of land carbon sink variability. Given that long-term trends are mostly associated with human impacts on the land carbon cycle, our proposed approach can offer valuable insights on the effectiveness of policy decisions and their implementation.

Abstract. Permafrost soils have the potential to release large amounts of soil carbon to the atmosphere under climate change. However, in the Sixth Coupled Model Intercomparison Project (CMIP6), only two Earth System Models (ESM) represented permafrost carbon, both sharing the same land surface model. This makes future permafrost carbon dynamics highly uncertain and underscores the urgent need to include permafrost carbon in ESMs to enable more reliable future projections of climate change and remaining carbon budget estimates. Here, we present IPSL-Perm-LandN, an improved version of the Institut Pierre-Simon Laplace (IPSL) ESM (used for CMIP6) aiming at better representing high-latitude land ecosystems. The main developments are the inclusion of an explicit nitrogen cycle and of key permafrost physical and biogeochemical processes. The latent heat associated with soil water freeze/thaw is taken into account in the energy budget, as well as soil thermal insulation by soil organic matter and a surface organic layer (e.g. litter or moss). Soil organic carbon and nitrogen are vertically resolved with depth-dependent decomposition dynamics, a key feature for representing the effect of gradual permafrost thaw on soil biogeochemistry. Cryoturbation is represented as a diffusion process that buries organic matter in the deeper soil layers. Compared to the previous version of the model used for CMIP6, we show that the extent of the permafrost region has improved significantly and that the simulated active layer thickness in the Arctic is in better agreement with observations. Permafrost soil carbon stocks have increased 20-fold to reach 1006 PgC in the top 3 m of soil, which is consistent with observation-based estimates. We simulate that the permafrost region has been a net carbon sink over the past 150 years (+0.32 ± 0.04 PgC yr−1 on average between 2005 and 2014), primarily due to carbon uptake from boreal forests. This is comparable with recent pan-Arctic carbon balance estimates, when accounting for unrepresented processes in our model (fire and riverine carbon losses). Overall, the inclusion of permafrost processes has improved the response of the model to anthropogenic perturbations in high latitudes over the past century, marking a step forward in the representation of Arctic ecosystems.

Climate change is currently reshaping Arctic ecosystems, with highly uncertain future outcomes. In the best-case scenario, warming could lead to the replacement of Arctic ecosystems by more diverse and productive sub-Arctic or temperate ecosystems, which may serve as net carbon sinks. However, recent research indicates that environmental disturbances caused by rapid warming could transform these ecosystems into heavily perturbed and degraded states, resulting in a net release of carbon to the atmosphere. The eventual outcome depends on the scale and pace of environmental changes, as well as the extent of other human disturbances in the region. To navigate these changes, we argue that it is crucial for Arctic nations to collaborate in monitoring and ecosystem-based management while developing policy-relevant pathways and scenarios to guide adaptation in a rapidly changing Arctic.

In response to the urgent demands of global climate governance, China has systematically integrated the green transition into its “dual-carbon” goals. The practical exploration of cultivated land emission reduction is not only crucial for promoting green transition but also embodies the synergistic effects of emission reduction and carbon sequestration in high-carbon-emission pressure areas. Existing studies have paid relatively less attention to high-carbon-emission pressure areas, necessitating more systematic research. In this study, we selected Henan Province as the study area and quantitatively analyzed the spatial-temporal differentiation of cultivated land net carbon sink from 2000 to 2023 along with their driving factors using an integrated methodological framework including Intergovernmental Panel on Climate Change (IPCC)-based carbon accounting, spatial autocorrelation analysis, and trajectory modeling. Analysis of the results indicates that the total net carbon sink of cultivated land in Henan Province showed a fluctuating yet overall upward trend with an average annual growth rate of 2.51%. The spatial distribution exhibits a pattern of “higher in the south and lower in the north” and “higher in the east and lower in the west”. This spatial pattern was significantly shaped by the cultivation area and fertilizer application intensity of three major crops—wheat, maize, and vegetables. Specifically, the net carbon sink contributions from these crops increased from 82.12% in 2000 to 85.93% in 2023, while the share of carbon emissions attributable to fertilizer use in the net carbon sink increased from 4.61% in 2000 to 5.22% in 2023, representing the activity with the largest contribution ratio among carbon emission activities. These findings provide valuable scientific evidence for further optimizing the green transition in high-carbon-emission areas and promoting the synergistic effects of emission reduction and carbon sequestration.

Abstract The pulp and paper industry is a promising yet underexplored platform for large-scale carbon dioxide removal (CDR) due to its use of biogenic feedstocks and production of concentrated CO 2 emissions from point sources. This study presents the first comprehensive life cycle assessment (LCA) of retrofitting an amine-based carbon capture and storage (CCS) system into a representative virgin kraft pulp and paper mill in the Southeastern U.S. We evaluate carbon removal across five system configurations, applying both static and dynamic LCA methods under multiple functional units: CO 2 captured, biomass input, and paper output. Results show that CCS retrofits can convert a conventional mill from a net emitter into a net carbon sink, with total removal efficiencies from 17% to 92% (metric tonnes of CO 2 removed per metric tonne of CO 2 available for removal under selected boundary conditions). When carbon removal is normalized to the quantity of biogenic CO 2 captured—a narrow, gate-to-gate system boundary that considers only CCS facility emissions—removal efficiencies reached as high as 92%. The use of such narrow boundaries aligns with precedents in traditional LCA methodology, where gate-to-gate assessments are commonly applied to isolate process-level performance and allocate emissions accordingly, providing a consistent basis for comparison across technologies. Under broader cradle-to-grave boundaries—which begin tracking carbon at the point of its physical removal from the atmosphere via photosynthesis in the forest, and extend to include upstream forest operations, mill-wide emissions, and downstream product decomposition—efficiencies declined, ranging from 17% to 46% under static assumptions and dropping to 12% when accounting for dynamic biogenic carbon fluxes over time. These results underscore how system boundary definitions influence reported outcomes, while also illustrating the complementary roles of narrow and broad perspectives for different decision-making contexts.

This study aims to investigate greenhouse gas (GHG) emissions from the Agriculture, Forestry, and Other Land Use (AFOLU) sector in Thailand's upper southern region, and to project future emissions through 2030 under two scenarios: Business-as-Usual (BAU) and the National Target (NT) scenario. The study area includes five provinces—Ranong, Chumphon, Nakhon Si Thammarat, Phatthalung, and Trang—characterized by abundant natural resources, including carbon-sequestering ecosystems such as mangrove forests. However, ongoing deforestation and agricultural expansion in these provinces have become major sources of GHG emissions, particularly methane (CH 4 ) from rice cultivation and livestock, and carbon dioxide (CO 2 ) from forest conversion. The study employs IPCC guidelines to assess current emissions and project future emissions up to 2030. Results indicate that the current GHG emissions from AFOLU are primarily from livestock (938,149 tons CO 2 -eq) and rice cultivation (261,745 tons CO 2 -eq). Under the BAU scenario, these emissions are projected to increase to 1.59 million tons CO 2 -eq and 292,793 tons CO 2 -eq, respectively. Net methane emissions are expected to rise, as reductions in rice emissions are outweighed by increases from livestock. Meanwhile, CO 2 emissions from deforestation are also projected to grow significantly. Implementation of mitigation measures under the NT scenario is projected to reduce emissions from livestock and rice cultivation by approximately 5 % and 17 %, respectively. Furthermore, to achieve the national GHG emission reduction targets, the application of regional and provincial-specific mitigation strategies—such as alternate wetting and drying techniques in rice paddies, improved manure management, and sustainable land-use practices—must align with both the local context and consistent national policies. • First sub-national assessment of GHG emissions from Thailand's AFOLU sector in the upper southern region using IPCC Tier 1 and localized activity data. • Integrated spatial analysis across five provinces reveals livestock as the dominant emission source, with methane emissions projected to increase by 70 % under BAU. • Forest land under BAU still functions as a net carbon sink, but sequestration potential improves significantly under NT with a projected 27 % increase in carbon removal. • Application of NT scenario results in measurable mitigation outcomes: 5 % reduction in livestock emissions, 17 % in rice cultivation, and 865,958 tCO 2 eq/year additional carbon sequestration from forests. • AWD rice techniques, biogas adoption, and forest expansion can aid Thailand's 40 % forest area target.

ABSTRACT Photovoltaic (PV) power generation has attracted significant attention not only for its substantial carbon reduction potential but also as an emerging research focus regarding its ecological impacts, particularly in arid and semi‐arid regions. The extensive construction of utility‐scale PV plants on the desert areas alters near‐surface microclimates, exerting non‐negligible influences on ecosystems. While utility‐scale PV plants significantly alter near‐surface microclimates, traditional models often fail to capture the intricate feedback mechanisms between PV panels and the underlying surface. To address this gap, this study developed a novel ecohydrological model that explicitly integrates a physically‐based PV canopy module into an existing ecohydrological model. Unlike conventional approaches, this model treats PV panels as a distinct canopy layer, allowing for the simultaneous resolution of energy and hydrological fluxes across the panel, vegetation and soil interfaces. Validated at the Kubuqi PV power plant, located in the arid region of Northern China, the model demonstrated satisfactory performance. Results reveal significant ecological benefits at the Kubuqi PV power plant: gross primary productivity (GPP) increased by 110 gC·m −2 during the growing season compared to the natural scenario, accompanied by a carbon sink enhancement of 58 gC·m −2 . This improvement is primarily attributed to a marked increase in water‐use efficiency (rising from 0.55 gC·m −2 ·mm −1 in the natural scenario to 1.12 gC·m −2 ·mm −1 in the PV scenario). Crucially, while the inter‐panel areas functioned as a net annual carbon sink, areas directly under the panels acted as a carbon source. Although vegetation growth under the panels was suppressed by hydrothermal constraints, it exhibited higher water‐use efficiency, indicating enhanced resource utilization under limiting conditions. This research advances the understanding of PV effects on ecohydrological processes in arid and semi‐arid areas and establishes a novel modelling framework integrating PV canopy influences for arid ecosystems.