Opportunities to tackle short-lived climate pollutants and other greenhouse gases for China

Opportunities beyond net-zero CO2 for cost-effective greenhouse gas mitigation in China

Achieving net-zero CO2 emissions is the current main focus of China's carbon neutrality goal. However, non-CO2 greenhouse gases (GHGs) are more powerful climate forcers, making their emission reduction an opportunity to rapidly mitigate future warming. Here, we evaluate non-CO2 mitigation potentials, costs and climate benefits in the context of China's carbon neutrality goals. The assessment is conducted by coupling the integrated assessment model GCAM with a climate emulator. The findings indicate that mitigation technologies can largely reduce fluorinated gas emissions from industrial sectors, but long-term non-CO2 reductions of energy sector activities rely heavily on fuel switching. Furthermore, the cumulative costs of deploying non-CO2 mitigation technologies are projected to be less than 10 % of the total costs of achieving carbon neutrality from 2020 to 2060. If non-CO2 mitigation measures are included in the overall mitigation portfolio, the benefits of avoided warming would by far outweigh the total mitigation cost increase. Our results thus highlight that incorporating a wider suite of GHGs into climate change mitigation strategies can enhance the cost-effectiveness of mitigation efforts.

The power of attention: Government climate-risk attention and agricultural-land carbon emissions

Climate change is a common challenge faced by all humanity. Promoting emission and carbon reduction in agricultural land is the most important priority for addressing climate change and realizing sustainable development. Based on data from 296 prefecture-level cities in China from 2011 to 2021, this study utilizes machine-learning and text-analysis methods to construct an indicator of government climate-risk attention (GCRA). It combines a two-way fixed-effects model to investigate how GCRA affects agricultural-land carbon emissions (ALCE) and carbon intensity (ALCI) and the mechanism of the impact. The results indicate that (1) GCRA substantially reduces ALCE and ALCI, and the conclusions are robust to a battery of tests. Furthermore, (2) mechanism analysis reveals that GCRA primarily uses three mechanisms-strengthening environmental regulation, promoting agricultural green-technology innovation, and upgrading agricultural-land mechanization-to reduce ALCE and lower ALCI. Additionally, (3) heterogeneity analysis suggests that the carbon-emission reduction effect of GCRA is more significant in the east, in arid and humid climate zones, and in non-grain-producing regions. Finally, (4) spatial-spillover effect analysis and quantile regression results demonstrate that GCRA also significantly inhibits carbon emissions and the carbon intensity of nearby agricultural land, with the inhibition effect becoming more pronounced at higher levels of government attention. This study's discoveries are helpful in promoting the emission reduction and carbon sequestration of agricultural land and provide references for developing countries to cope with climate change.

How to effectively achieve air pollutant reduction and carbon mitigation in China's industrial sector? A study based on decomposition analysis and scenario simulation

Reducing air pollutant and carbon emissions in the industrial sector is crucial for the ecological civilization construction in China. In this study, we first employ the generalized Divisia index method to analyze the driving factors of industrial CO2 and SO2 emissions, incorporating fixed asset investment and R&D input. The key sub-sectors that exert significant impact on emissions of the whole industrial sector are identified. And then, scenario analysis and Monte Carlo simulation are utilized to predict future trends and potential for reducing CO2 and SO2 emissions. Furthermore, the carbon peaking time of the industrial sub-sectors is investigated. The results indicate that fixed asset investment and R&D input both have played positive roles in CO2 and SO2 emissions. Emission reduction is mainly driven by investment emission intensity, output emission intensity, and R&D emission intensity. Sub-sectors S09, S10, S11, S12, and S18 present substantial potential for reducing air pollutant and carbon emissions. Although SO2 emissions from the industrial sector are projected to decrease in the future, the peak of CO2 emissions have not been reached. The carbon peak time for the whole industrial sector is predicted in 2025, with the peak of 7892.33 Mt. The five key sub-sectors are anticipated to reach the respective carbon emission peaks at different times. Therefore, to effectively implement industrial air pollutant and carbon reduction, the role of fixed asset investment and R&D input should be fully utilized, and high-energy consumption and high-emission sub-sectors should be prioritized for action.

Recent progresses, challenges and proposals on SF6 emission reduction approaches

The increasing utilization and emission of sulfur hexafluoride (SF6) pose severe threats to the climate and the environment, owing to its potent greenhouse gas properties. In this paper, we comprehensively review the recent progresses of SF6 emission reduction approaches. Currently, the use and emission of SF6 are still on the rise, and mainly concentrated in the power industry. Restrictive use and emission reduction policies are fundamental step in guiding SF6 emission, but they are poor promoted in developing economies. More specific policies and regulations are needed in conjunction with timely and accurate assessments of SF6 atmospheric properties and emissions. SF6 recovery is the direct emission reduction approach, but defects in recovery methods and equipment limit its applications. The development of SF6 purification technologies and optimizations in recovery devices and processes are needed for its treatment of different regions and SF6 volumes. SF6 degradation is the final step of waste gas treatment, and its development needs to better balance the degradation rate and product selectivity, as well as to improve their multi-scenario responsiveness. SF6 substitution is a necessity for future large-scale SF6 emission reduction. Improvements in SF6-free applications and its long-term stability are critical via new gas design, gas mixture optimization and equipment updates. Finally, all the emission reduction approaches are closely related, and promoting their synergistic development and complementarity is the ultimate way to realize SF6 lifecycle management.

Nanoremediation strategies to address environmental problems

A rapid rise in population, extensive anthropogenic activities including agricultural practices, up-scaled industrialization, massive deforestation, etc. are the leading causes of environmental degradation. Such uncontrolled and unabated practices have affected the quality of environment (water, soil, and air) synergistically by accumulating huge quantities of organic and inorganic pollutants in it. Environmental contamination is posing a threat to the existing life on the Earth, therefore, demands the development of sustainable environmental remediation approaches. The conventional physiochemical remediation approaches are laborious, expensive, and time-consuming. In this regard, nanoremediation has emerged as an innovative, rapid, economical, sustainable, and reliable approach to remediate various environmental pollutants and minimize or attenuate the risks associated with them. Owing to their unique properties such as high surface area to volume ratio, enhanced reactivity, tunable physical parameters, versatility, etc. nanoscale objects have gained attention in environmental clean-up practices. The current review highlights the role of nanoscale objects in the remediation of environmental contaminants to minimize their impact on human, plant, and animal health; and air, water, and soil quality. The aim of the review is to provide information about the applications of nanoscale objects in dye degradation, wastewater management, heavy metal and crude oil remediation, and mitigation of gaseous pollutants including greenhouse gases.