Black carbon (BC) is a major short-lived climate pollutant (SLCP) with significant climate and environmentalhealth impacts. This review synthesizes critical advancements in the identification of emerging anthropogenic BC sources, updates to global warming potential (GWP) and global temperature potential (GTP) metrics, technical progress in characterization techniques, improvements in global-regional monitoring networks, emission inventory, and impact assessment methods. Notably, gas flaring, shipping, and urban waste burning have slowly emerged as dominant emission sources, especially in Asia, Eastern Europe, and Arctic regions. The updated GWP over 100 years for BC is estimated at 342 CO2-eq, compared to 658 CO2-eq in IPCC AR5. Recent CMIP6-based Earth System Models (ESMs) have improved attribution of BC's microphysics, identifying a 22 % increase in radiative forcing (RF) over hotspots like East Asia and Sub-Saharan Africa. Despite progress, challenges persist in monitoring network inter-comparability, emission inventory uncertainty, and underrepresentation of BC processes in ESMs. Future efforts could benefit from the integration of satellite data, artificial intelligence (AI)assisted methods, and harmonized protocols to improve BC assessment. Targeted mitigation strategies could avert up to four million premature deaths globally by 2030, albeit at a 17 % additional cost. These findings highlight BC's pivotal roles in near-term climate and sustainability policy.

Light-absorbing carbonaceous aerosols, comprising black carbon (BC) and brown carbon (BrC), significantly influence air quality and radiative forcing. Unlike traditional approaches that use a fixed value of absorption & Aring;ngstrom exponent (AAE), this study investigated the absorption and optical properties of carbonaceous aerosols in Beijing for both local emission and regional transport events during a wintertime pollution event by using improved AAE results that employs wavelength-dependent AAE (WDA). By calculating the difference of BC AAE at different wavelengths using Mie theory and comparing the calculated results to actual measurements from an Aethalometer (AE31), a more accurate absorption coefficient of BrC can be derived. Through the analysis of air mass sources, local emission was found dominated the pollution events during this study, accounting for 81 % of all cases, while regional transport played a minor role. Carbonaceous aerosols exhibited a continuous increasing trend during midday, which may be attributed to the re-entrainment of nighttime-accumulated carbonaceous aerosols to the surface during the early planetary boundary layer (PBL) development phase, as the mixed layer rises, combined with the variation of PBL and anthropogenic activity. At night, variations in the PBL height, in addition to anthropogenic activities, effectively contributed to surface aerosol concentrations, leading to peak surface aerosol values during local pollution episodes. The diurnal variation of AAE470/880 exhibited a decreasing trend, with a total decrease of approximately 12 %. Furthermore, the BrC fraction showed a constant diurnal variation, suggesting that the declining AAE470/880 was primarily influenced by BC, possibly due to enhanced traffic contributions.

Permafrost degradation under climate warming plays a crucial role in hydrological and ecological processes, including the regional water cycle and terrestrial carbon balance. The Tibetan Plateau (TP), which contains the largest expanse of high-altitude permafrost globally, remains understudied in terms of how permafrost degradation affects surface water resources and regional carbon dynamics. Using permafrost simulation models and quantitative analysis, we assess the spatiotemporal impacts of permafrost degradation on surface water resources and carbon dynamics. In the inner endorheic regions of the TP, ground ice meltwater contributed 12.6% of the total lake volume increase from 2000 to 2020, accelerating lake expansion and affecting nearby infrastructure and ecosystems. Cryospheric meltwater accounted for 4.6% of total runoff in the source areas of the Yangtze, Yellow, Lancang, Yarlung Zangbo, and Nujiang Rivers in 2002-2018. This cryospheric meltwater contribution is projected to peak in the 2030s-2040s, followed by a decline, with potentially profound implications for downstream water availability. From 2000 to 2020, carbon sequestration of alpine grassland in permafrost regions is 1.05-1.29 Tg C a-1 in 2000-2020. This estimate is underestimated by approximately 35.5% to 48.1% without considering the impact of permafrost degradation. Top-down thawing of permafrost from 2002 to 2050 is projected to release 129.39 +/- 21.02 Tg C a-1 of thawed soil organic carbon (SOC), with 20.82 +/- 3.06 Tg C a-1 decomposed annually. Additionally, permafrost collapse and thermokarst lake are estimated to reduce ecosystem carbon sinks by 0.41 (0.29-0.52) Tg C a-1 in 2020. (c) 2025 The Authors. Published by Elsevier B.V. and Science China Press. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Carbonaceous aerosols play a crucial role in air pollution and radiative forcing, though their light-absorbing and isotopic characteristics remain insufficiently understood. This study analyzes optical absorption and isotopic composition in PM10 and PM2.5 particles from primary emission sources, focusing on traffic-related and solid fuel categories. We analyzed key optical properties, including the Angstrom absorption exponent (AAE), the contributions of black carbon (BC) and brown carbon (BrC) to total light absorption and the mass absorption efficiencies (MAE) of carbonaceous aerosols. AAE values were lower for traffic emission sources (0.9 to 1.3) than solid fuel emission sources (1.5 to 3), with similar values for both particle sizes. BrC contributions were more prominent at shorter wavelengths and were notably higher in solid fuel emission sources (61% to 88%) than in traffic emission sources (8% to 40%) at 405 nm. MAE values of BC at 405 nm were 2 to 20 times higher than BrC across different emissions. Particle size significantly affect MAE(BC) with PM2.5 higher when compared to PM10. Emissions from diesel concentrate mixer and raw coal burning exhibited the highest MAE(BC) for PM2.5 and PM10, respectively. Conversely, Coke had the lowest MAE(BC) but the highest MAE(BrC) for both sizes. Traffic emissions showed more stable carbon isotope ratios (delta C-13) enrichment (-29 parts per thousand to -24 parts per thousand) than solid fuels (-31 parts per thousand to -20 parts per thousand). delta C-13 of solid fuel combustion, unlike traffic sources, is found to be independent of size variation. These findings underscore the importance of source and size-specific aerosol characterization for unregulated emission sources.

The present paper sets out a comparative analysis of carbon emission and economic benefit of different performance gradients solid waste based solidification material (SSM). The macro properties of SSM were the focus of systematic study, with the aim of gaining deeper insight into the response of the SSM to conditions such as freeze-thaw cycles, seawater erosion, dry-wet cycles and dry shrinkage. In order to facilitate this study, a range of analytical techniques were employed, including scanning electron microscopy (SEM), X-ray diffraction (XRD) and mercury intrusion porosimetry (MIP). The findings indicate that, in comparison with cement, the carbon emissions of SSM (A1) are diminished by 77.7 %, amounting to 190 kg/t, the carbon-performance ratio (24.4 kg/ MPa), the cost-performance ratio (32.1RMB/MPa) and the carbon-cost ratio (0.76kg/RMB) are reduced by 86 %, 56 % and 68 % respectively. SSM demonstrated better performance in terms of freeze-thaw resistance, seawater erosion resistance and dry-wet resistance when compared to cement. The dry shrinkage value of SSM solidified soil was reduced by approximately 35 % at 40 days compared to cement solidified soil, due to compensatory shrinkage and a reduction in pores. In contrast to the relatively minor impact of seawater erosion and the moderate effects of the wet-dry cycle, freeze-thaw cycles have been shown to cause the most severe structural damage to the micro-structure of solidified soil. The conduction of durability tests resulted in increased porosity and the most probable aperture. The increase in pores and micro-structure leads to the attenuation of macroscopic mechanical properties of SSM solidified soil. The engineering application verified that with the content of SSM of 50 kg/m, 4.5 % and 3 %, the strength, bearing capacity and bending value of SSM modified soil were 1.9 MPa, 180 kPa and 158, respectively in deep mixing piles, shallow in-situ solidification, and roadbed modified soil field.

The terrestrial program of the Arctic Challenge for Sustainability-II (ArCS II) is dedicated to clarifying the complex responses of Arctic boreal ecosystems and biogeochemical cycles to a warming climate. Focusing on ecosystem function, terrestrial greenhouse gas dynamics, and permafrost and biogeochemical cycles, ArCS II targets key challenges posed by climate change across terrestrial ecosystems. Biodiversity and ecosystem function research emphasizes the interactions between plant and soil microbial communities across Arctic boreal regions, with discoveries such as new fungal species contributing valuable information elucidating the status of Arctic ecosystems. Our study revealed that vegetation has a significant impact on the composition and network structure of microbial communities, and these interactions may influence ecosystem responses to environmental changes. Greenhouse gas dynamics were analyzed using long-term carbon and methane emissions data collected in boreal forests, tundra, wetlands, and glacial termini, as emissions from these regions can accelerate warming. Plant-mediated methane transport was identified as the primary process driving methane emission from wetlands, and elevated methane concentrations were detected in some glacial meltwaters. ArCS II advances permafrost modeling to assess the impacts of thawing on terrestrial processes, emphasizing freeze-thaw cycles and their impact on greenhouse gas dynamics. Excess ice formed within permafrost plays a role in suppressing permafrost warming and may induce anomalous variations in greenhouse gas emissions. Despite limitations imposed on field surveys by COVID-19, the ArCS II project elucidated ecosystem changes using long-term data. ArCS II terrestrial research lays a foundation for the exploration of climate impacts on Arctic boreal ecosystems.

This paper investigated the influence of chloride ion erosion and aftershocks on the seismic performance of transmission tower structures in Xinjiang, China. Based on chloride ion diffusion laws and steel corrosion mechanisms, the time-dependent deterioration of reinforced concrete was analyzed. Finite element models considering corrosion effects were established for different ages(0a,50a,70a,100a) in a saline soil environment using ANSYS/LS-DYNA. Ten mainshock-aftershock sequences tailored to the site type was constructed, and the cumulative damage index (DI) was adopted as a metric for structural damage. The results indicate that aftershocks and steel corrosion significantly impact transmission tower damage, with damage extent influenced by the intensity of the main shock. Stronger aftershocks cause greater additional damage, potentially exceeding 50 % cumulative damage when their amplitude matches the main shock. Steel corrosion alone can lead to nearly 40 % damage. Its influence on seismic fragility varies with damage state, especially under moderate to complete damage, where longer service life increases vulnerability. The coupling of corrosion and aftershocks further elevates structural vulnerability. Hence, in seismic assessments of transmission towers in saline soil environments, combined effects of main and aftershocks, and corrosion, must be accounted for.

CONTEXT: Policy issues in most nations include adapting primary agricultural production to reduce greenhouse gas (GHG) emissions. Commitments have been established through multi-lateral agreements targeting GHG emission reductions to abate climate change impacts. In response to policy initiatives targeted at industries such as agriculture, producers are adopting innovative production methods and technologies to provide environmental services and mitigate emissions. GHG emissions arising from livestock production contribute to a damaging narrative surrounding agriculture, particularly beef production. OBJECTIVE: The purpose of this study is three-fold, quantifying (a) net emissions,2 (b) changes in practice, and (c) economic outcomes attributed to the forage production facet of cow-calf production. METHODS: The Saskatchewan Forage Production Survey was developed to gather forage management practices data, placing emphasis on land use and land management changes. Canada's whole-farm assessment model, Holos, was applied as a carbon accounting framework to derive the net emissions of the forage production cycle. RESULTS AND CONCLUSIONS: Results indicate carbon sequestration increased between the periods of 1991-94 and 2016-19. Gross emissions decreased to a larger degree and net emission results for the forage production facet of the Saskatchewan cow calf sector are -0.123 Mg CO2e/ha/yr in 2016-19. SIGNIFICANCE: Recommendations include the renewal of forage rejuvenation funding programs that may improve forage yields and carbon sequestration potential. Further, the expansion of term conservation easement programs to include non-native forage lands is recommended to incentivize the retention of forage land.

Widespread changes to near-surface permafrost in northern ecosystems are occurring through gradual top-down thaw and more abrupt localized thermokarst development. Both thaw types are associated with a loss of ecosystem services, including soil hydrothermal and mechanical stability and long-term carbon storage. Here, we analyzed relationships between the vascular understory, basal moss layer, active layer thickness (ALT), and greenhouse gas fluxes along a thaw gradient from permafrost peat plateau to thaw bog in Interior Alaska. We used ALT to define four distinct stages of thaw: Stable, Early, Intermediate, and Advanced, and we identified key plant taxa that serve as reliable indicators of each stage. Advanced thaw, with a thicker active layer and more developed thermokarst features, was associated with increased abundance of graminoids and Sphagnum mosses but decreased plant species richness and ericoid abundance, as well as a substantial increase in methane emissions. Early thaw, characterized by active layer thickening without thermokarst development, coincided with decreased ericoid cover and plant species richness and an increase in CH4 emissions. Our findings suggest that early stages of thaw, prior to the formation of thermokarst features, are associated with distinct vegetation and soil moisture changes that lead to abrupt increases in methane emissions, which then are perpetuated through ground surface subsidence and collapse scar bog formation. Current modeling of permafrost peatlands will underestimate carbon emissions from thawing permafrost unless these linkages between plant community, nonlinear active layer dynamics, and carbon fluxes of emerging thaw features are integrated into modeling frameworks.

We present a high-resolution geologic map of the Rubin crater region, located on Mons Amundsen, which has been identified as a promising site for future lunar exploration (AOI E in Wueller et al., 2024). We developed a design reference mission (DRM) to highlight the region's potential for addressing key lunar science goals, particularly those related to the early lunar bombardment history, lunar crustal rocks, volatiles, impact processes at multiple scales, and regolith properties, as outlined by the National Research Council (2007). The Rubin crater, which formed about 1.58 billion years ago during the Eratosthenian period, excavated material from depths of up to 320 m, potentially reaching the underlying South Pole-Aitken (SPA) massif, Mons Amundsen. This makes the crater's ejecta material, along with the Amundsen ejecta covering the massif, prime targets for sampling SPA-derived materials that can expand our understanding of early Solar System dynamics and the lunar cratering chronology. Additionally, the region hosts several permanently shadowed regions (PSRs), ideal for studying potential lunar volatiles and the processes affecting their distribution. The DRM proposes nine traverse options for exploration via walking EVAs, the Lunar Roving Vehicle (LRV), and LRV-assisted EVAs, with traverse lengths ranging from 3.6 km to 18.2 km. Each traverse is designed to sample diverse geologic units and address multiple scientific objectives. Given its scientific potential and favorable exploration conditions, the Rubin crater region is an ideal location for testing south polar landing operations, potentially paving the way for more complex missions, such as a Shackleton crater landing. (c) 2025 The Author(s). Published by Elsevier B.V. on behalf of COSPAR. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).