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Accurate estimate of the size of land carbon sink is essential for guiding climate mitigation actions to fulfill China's net-zero ambitions before 2060. The atmospheric inversion is an effective approach to provide spatially explicit estimate of surface CO 2 fluxes that are optimally consistent with atmospheric CO 2 measurements. But atmospheric inversion of China's land carbon sink has enormous uncertainties, with one major source arising from the poor coverage of CO 2 observation stations. Here we use a regional atmospheric inversion framework to design an observation network that could minimize uncertainties in inverted estimate of China's land carbon sink. Compared with the large spread of inverted sink (∼1 Pg C a−1) from state-of-the-art inversions using existing CO 2 observations, the uncertainty is constrained within 0.3 Pg C a−1 when a total of 30 stations were deployed, and is further reduced to approximately 0.2 Pg C a−1 when 60 stations were deployed. The proposed stations are mostly distributed over areas with high biosphere productivity during the growing season, such as Southeast China, Northeast China, North China, and the Tibetan Plateau. Moreover, the proposed stations can cover areas where existing satellites have limited coverage due to cloud shadowing in the monsoon season or over complex topography. Such ground-based observation network will be a critical component in the future integrated observing system for monitoring China's land carbon fluxes. [ABSTRACT FROM AUTHOR]

Urban residential carbon dioxide (CO2) emissions have increased sharply along with the rapid urbanization process. Few studies have considered the different effects of influencing factors between Northern and Southern China, and the analysis of CO2 per unit area from the spatial perspective is also rarely involved. Using the spatial Durbin model (SDM), this study aimed at revealing the influencing factors (including income, inequality, population density, urban morphology, etc.) on CO2 per capita and CO2 per unit area during 2001–2018 between Northern and Southern China. The results showed that the Northern cities had higher carbon emissions and a faster growth rate, and the high-high clusters were also mainly located in the Northern cities. The Gini coefficient was correlated adversely with CO2, while income imposed a positive effect on carbon emissions. The negative coefficients of the quadratic term of the GDP per capita demonstrated that the residential carbon emissions have the potential to decrease when the income increases to a certain level. The indirect effects of income and the Gini showed that spatial spillover effects exist. Urban population density and the ratio of residential area to built-up area had an opposite effect on CO2 per capita and CO2 per unit area, and they have a bigger impact on the CO2 per unit area. This study revealed the different roles of various factors in reducing CO2 per unit area from the spatial perspective and CO2 per capita from the non-spatial perspective between the Northern and Southern regions, which could help policymakers to design targeted mitigation measures in the residential sector in China, providing references for developing countries to jointly reduce carbon emissions to promote the mitigation of global climate change. [ABSTRACT FROM AUTHOR]

Natural 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. The 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. The Denitrification-Decomposition (DNDC) model was used to estimate the NGHG, including SOC sequestration, N 2 O emissions, and CH 4 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. The 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 CO 2 -eq, 116.3 Tg CO 2 -eq, 35.2 Tg CO 2 -eq, and 74.4 Tg CO 2 -eq, respectively. The integrated optimal management may potentially reduce NGHG by 256.9 Tg CO 2 -eq, equivalent to 90.2% of current NGHG, and 80% of which can be realized at the price of CN¥ 285 (Mg CO 2 -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. Our 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. [Display omitted] • Estimating net greenhouse gas emissions (NGHG) reduction potentials of agriculture. • IPCC recommended tier 3 method was applied for seven cropping systems in China. • The integrated optimal management may potentially reduce NGHG by 256.9 Tg CO 2 -eq. • 80% of NGHG mitigation can be realized at the price of CN¥ 285 (Mg CO 2 -eq)−1. • The priority NCS was identified for different crops and regions. [ABSTRACT FROM AUTHOR]

Planning power system (PS) towards renewable energy is crucial for reducing carbon dioxide (CO 2) emission as well as mitigating climate change. However, the inherent uncertainty and hierarchical structure of PS pose intractable challenges to the planning process. This study develops a multi-GCM-based interval bi-level programming (MIBP) method that can balance two-level decision-making conflict between CO 2 -emisison reduction and system cost minimization. MIBP can also deal with uncertainties expressed as interval values in objective functions and constraints. Then, a MIBP-PS model is formulated to plan PS for China (2021–2050), where the upper-level objective is to minimize CO 2 emission and the lower-level objective is to minimize the system cost. The major findings are: (i) the CO 2 emission for PS would reach peak value before 2030 and then reduce by [10.2, 20.4]% in 2050, which is mainly owing to the curtailment of fossil fuel; (ii) compared with the conventional model, CO 2 emission from MIBP-PS model could decrease by [3.1, 4.8]%, which shows the superiority of the developed model; (iii) the fossil-fuel power would be gradually replaced by renewable energy, and the proportion of coal-fired power would decrease by 38.8% by 2050, especially small coal-fired facilities (i.e., below 0.3 GW) should be gradually phased down. [Display omitted] [ABSTRACT FROM AUTHOR]

Clean vehicle fleet will greatly benefit air quality and climate change mitigation. Here, we employ an integrated model to systematically investigated the contribution of combined clean vehicle policies to "emissions, exposure, and health benefits" from a regional perspective 2019–2035 in China. We find that driven by clean vehicle polices, the national vehicle CO 2 will likely to peak around 2028 with about 1327 million tons, and then reduce by 7.8% from 2028 to 2035. The developed region will peak CO 2 before 2030, while the developing region probably peak after 2030. In general, most air pollutants emissions from vehicles will decrease, subsequently leading to obvious PM 2.5 and O 3 exposure decrease. About 68 thousand PM 2.5 related and 33 thousand O 3 related deaths will be avoided 2019–2035 nationwide. Note that the health benefits are unequal, with higher PM 2.5 -O 3 related excess deaths be avoided per 100000 in developed region than developing region. Besides, results show that emission standard upgrade contributes largest to emission reduction and related health benefits, followed by electric vehicles, road-to-railways and waterways, and fuel consumption regulation in general. This work is able to provide valuable information for policy makers to collaboratively reduce CO 2 , air pollutants and premature deaths in China and other developing countries. [Display omitted] • Emissions in CO 2 and air pollutants were both investigated based on a dataset with 27 vehicle categories from 338 cities. • The contribution of vehicle clean policies to abated PM 2.5 -O 3 exposure and related deaths was quantified and decomposed. • This work proposed region-specific clean vehicle pathways from a national and regional perspective 2019-2035. [ABSTRACT FROM AUTHOR]

• CO 2 sequestration and EGR are experimentally evaluated in two shale gas reservoirs. • Pore heterogeneity and connectivity are evaluated via multifractal analysis. • Shale composition controls on gas storage is evaluated from gas adsorption measurements. • Links between MICP and gas adsorption measurements were used to evaluate EGR suitability. In the global effort toward climate change mitigation, geologic storage of CO 2 in shale plays is becoming critical while it can improve production from these reservoirs. In this study, the gas storage capacity and CO 2 sequestration suitability of the Longmaxi and Niutitang shale gas reservoirs is investigated and compared via XRD analysis, programmed pyrolysis, low pressure N 2 and CO 2 adsorption, high pressure CH 4 adsorption, and MICP analysis. Results showed that clay and TOC controls on micropore heterogeneity and connectivity happens only within the Longmaxi Formation. Furthermore, both components play a role in the adsorbed quantities of gas in the formation which revealing a higher storage capacity in mesopore-macropores. This was verified by a positive correlation between adsorbed volume within the mesopore-macropore space. The Longmaxi Formation was also found to own better pore connectivity and PSD homogeneity of mesopore-macropores, indicating easier pathways for CO 2 movement channels within the pore network. Furthermore, the samples from the Longmaxi exhibited a positive relationship between adsorbed volume with the CO 2 breakthrough pressure and median pore diameter, alike between the mesopore-macropore volume and CO 2 breakthrough pressure. This means, the injected CO 2 will displace adsorbed methane within the mesopore-macropore and will be adsorbed and stored in such pores. Overall, superiority of the Longmaxi shale over the Niutitang for CO 2 storage and EGR would be significant for future operations in similar shale gas reservoirs in China and around the globe. [ABSTRACT FROM AUTHOR]

City clusters play an important role in air pollutant and greenhouse gas (GHG) emissions reduction in China, primarily due to their high fossil energy consumption levels. The "2 + 26" Cities, i.e., Beijing, Tianjin and 26 other perfectures in northern China, has experienced serious air pollution in recent years. We employ the Greenhouse Gas and Air Pollution Interactions and Synergies model adapted to the "2 + 26" Cities (GAINS-JJJ) to evaluate the impacts of structural adjustments in four major sectors, industry, energy, transport and land use, under the Three-Year Action Plan for Blue Skies (Three-Year Action Plan) on the emissions of both the major air pollutants and CO 2 in the "2 + 26" Cities. The results indicate that the Three-Year Action Plan applied in the "2 + 26" Cities reduces the total emissions of primary fine particulate matter with an aerodynamic diameter of ≤ 2.5 μm (PM 2.5), SO 2 , NO x , NH 3 and CO 2 by 17%, 25%, 21%, 3% and 1%, respectively, from 2017 to 2020. The emission reduction potentials vary widely across the 28 prefectures, which may be attributed to the differences in energy structure, industrial composition, and policy enforcement rate. Among the four sectors, adjustment of industrial structure attains the highest co-benefits of CO 2 reduction and air pollution control due to its high CO 2 reduction potential, while structural adjustments in energy and transport attain much lower co-benefits, despite their relatively high air pollutant emissions reductions, primarily resulting from an increase in the coal-electric load and associated carbon emissions caused by electric reform policies.. • Impacts of structural adjustments on emissions of air pollutants and CO 2 in the "2 + 26" Cities are evaluated. • The higher the pollutant emissions are, the higher the reduction potential. • Adjustment of industrial structure attains the highest co-benefits of CO 2 reduction and air pollution control. [ABSTRACT FROM AUTHOR]

[Display omitted] • TUEEC in 10 urban agglomerations in China are substantially different. • TUEEC within urban agglomeration have an impact on CO 2 emissions. • Ecological construction partially mitigated emissions growth. • Guarding against unsustainable development is vital to carbon neutral. Urban agglomerations are major generators of CO 2 emissions owing to human socioeconomic activities. Evaluating the trade-offs between urban expansion and ecological construction during rapid urbanization is a crucial step towards climate change mitigation and carbon neutrality. This study investigated the impacts of trade-offs between urban expansion and ecological construction on CO 2 emissions using multi-source data and spatial and statistical analysis. Ten urban agglomerations in China, with various development levels, were selected as study areas. The results indicated that (1) urban development in the 10 urban agglomerations expanded by 90%–288.9%, while ecological land changed by −28.1–2.3%. (2) CO 2 emissions grew by 154.2–291.2% in urban agglomerations, and the south and east of China emitted more CO 2. The high-value clusters of CO 2 inside of all urban agglomerations expanded outward from cities. (3) Urban expansion increased emissions, while ecological construction partially mitigated emissions growth. Moreover, ecological development within cities helps to reduce excessive urban emissions and should be given more attention. (4) It is as important to guard against unsustainable development as it is to reduce existing high emissions. Low-carbon development paths must continue to be supported in western China. On the basis of the results, we identify important implications for meeting China's target of carbon neutrality. These contribute to an understanding of future development modes for urban agglomerations and reveal the impact of trade-offs of land use on CO 2 emissions. [ABSTRACT FROM AUTHOR]

Carbon Capture, Utilization and Storage, also referred to as Carbon Capture, Utilization and Sequestration (CCUS), is one of the novel climate mitigation technologies by which CO2 emissions are captured from sources, such as fossil power generation and industrial processes, and further either reused or stored with more attention being paid on the utilization of captured CO2. In the whole CCUS process, the dominant migration pathway of CO2 after being injected underground becomes very important information to judge the possible storage status as well as one of the essential references for evaluating possible environmental affects. Interferometric Synthetic Aperture Radar (InSAR) technology, with its advantages of extensive coverage in surface deformation monitoring and all-weather traceability of the injection processes, has become one of the promising technologies frequently adopted in worldwide CCUS projects. In this study, taking the CCUS sequestration area in Shizhuang Town, Shanxi Province, China, as an example, unmanned aerial vehicle (UAV) photography measurement technology with a 3D surface model at a resolution of 5.3 cm was applied to extract the high-resolution digital elevation model (DEM) of the study site in coordination with InSAR technology to more clearly display the results of surface deformation monitoring of the CO2 injection area. A 2 km surface heaving dynamic processes before and after injection from June 2020 to July 2021 was obtained, and a CO2 migration pathway northeastward was observed, which was rather consistent with the monitoring results by logging and micro-seismic studies. Additionally, an integrated monitoring scheme, which will be the trend of monitoring in the future, is proposed in the discussion. [ABSTRACT FROM AUTHOR]

Promoting technology development co-operation is particularly relevant while addressing global climate change or regional pollution. Investors may contribute to increasing environmental-related patents, which may help to improve the quality of the environment as long as supported by proper regulations and policies. In the quest towards a cleaner environment via the mitigation of climate change, this study investigates the relationship between technological innovation, income level, renewable energy and carbon emissions in both the United States and China. Applying the dynamic auto-regressive distributive lag (DARDL) simulation method revealed varying impacts of regressors on CO 2 emissions in the short-run and long-run. Accordingly, this study empirically confirms that (i) technological innovation reduces carbon emissions in the United States but it is not statistically significant in China. (ii) Renewable energy reduces carbon emissions in both countries. (iii) The impact of income level on emissions decreases from short-run to long-run in both countries. Decision-makers in China should stimulate more effective environmental-related innovations to decrease CO 2 emissions and should permit easy access to environmental-related patents together with reducing its cost of registration. • Investigates the role of green technological innovation in decreasing CO 2 emissions. • Applies the novel Dynamic ARDL simulation. • Green technological innovation reduces CO 2 emissions in the U.S. Only. • Confirms that renewable energy mitigates CO 2 emissions both in the U.S. and China. [ABSTRACT FROM AUTHOR]