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Livestock is an important source of greenhouse gas emissions (GHGE) in China. Understanding the greenhouse gas (GHG) emission trends and reduction strategies in livestock is crucial for promoting low-carbon transformation of the livestock sector (LS) and achieving the goal of "carbon peak and carbon neutralization". First, based on the life cycle assessment and IPCC coefficient methods, we calculated the GHGE of the LS in 31 provinces of China from 2000 to 2020 and identified the temporal and spatial evolution of GHG emission intensity. The LMDI method was then used to analyze the influence of efficiency, structure, economy, and population size on GHGE. Finally, the STIRPAT model was used to simulate the future evolution trend of the LS emissions under the SSPs scenario. The results revealed that the GHGE in the life cycle of livestock production decreased from 535.47 Mt carbon dioxide equivalent (CO 2 e) in 2000 to 532.18 Mt CO 2 e in 2020, and the main source was CH 4 emissions from enteric fermentation of livestock. Economic and efficiency factors markedly influenced the changes in GHGE from the LS in China. Further, economic factors contributed >40% to the increase in GHGE in most provinces. Under the SSP1, SSP2, and SSP4 scenarios, livestock production can achieve the carbon peak target in 2030. Under the baseline scenario (SSP2), the GHGE of China's LS in 2030 and 2060 are expected to be 491.48 Mt CO 2 e and 352.11 Mt CO 2 e, respectively. The focus of mitigation measures for livestock production in the future is to optimize the production structure of the LS, promote the low-carbon transformation of the energy structure of livestock feeding, and establish an efficient and intensive management model. In addition, we focus on emission reduction in key areas, such as Northeast and Northwest China, while optimizing diet and reducing food waste from the consumer side. • GHGE during the livestock production from 2000 to 2020 fluctuated between 500.77 and 670.98 Mt CO 2 e. • GHGE per unit output value of LS were decreasing annually. • Economic and efficiency factors were the main reasons for the change in GHGE from livestock production in China. • The GHGE from the LS are expected first to increase and then decrease between 2021 and 2060. • The LS has the highest emission reduction potential under SSP1, SSP2, and SSP4 scenarios. [ABSTRACT FROM AUTHOR]

The transfer characterization of greenhouse gas from agricultural sources in the food trade is important to ensure food security and mitigate climate change. In this study, a spatial equilibrium model was established to simulate the trade flow patterns of grains and meat in China from 2000 to 2020 and the greenhouse gas from agricultural sources implied therein. This identified coupling relationship between production and greenhouse gas emissions. The results showed that the separation of supply and demand in food trade led to greenhouse gas transfers and flows that were similar to the food trade pattern. The total greenhouse gas transfer from grains decreased. However, that from meat increased from 13.91 Mt CO 2 -eq to 41.89 Mt CO 2 -eq, while the cross-regional transfer share increased from 47.86% to 59.16%. This study provides a benchmark for the better formulation of policies for zonal greenhouse gas reduction from agricultural sources. [Display omitted] [ABSTRACT FROM AUTHOR]

Atmospheric carbon dioxide (CO 2) has affected global surface and atmospheric energy balance since the Industrial Revolution. The spatial distribution of CO 2 concentrations derived from satellite observation are introduced into the coupled Beijing Normal University Earth System Model (BNU-ESM) to study the responses of temperature and surface energy balance to non-uniform CO 2 distribution under the Representative Concentration Pathway 8.5 scenario to 2100. Global annual mean atmospheric CO 2 concentrations are set to equal those specified in the standard uniform CO 2 simulations with differences in spatial pattern and seasonal cycles amounting to tens of ppm. Relative to the uniform CO 2 simulation, global annual mean surface air temperature increases by 0.44 ± 0.03 °C over 2071–2100 when forced with non-uniformly distributed CO 2 , in the Arctic by 1.63 ± 0.28 °C and by 0.67 ± 0.08 °C in northern midlatitudes. The non-uniform CO 2 simulation increases global surface energy by 0.68 ± 0.06 W m−2, principally due to a 0.73 ± 0.08 W m−2 increase in net downward surface longwave flux. Surface energy balance increases by 0.33 ± 0.11 W m−2 (7.4%) averaged over oceans indicting a significant increase in ocean heat uptake. Surface energy budget averaged over the Arctic summer increases by 0.91 ± 0.68 W m−2 in the non-uniform CO 2 simulation, which would have impact on sea ice extent and land ice melt rates with associated feedbacks. The increased surface energy fluxes and temperatures imply reduced time and emission space for greenhouse gases before running into scientific and politically flagged temperature limits. • The distributions of CO 2 concentrations are introduced into Earth System Model. • There are some changes in surface energy fluxes due to non-uniform CO 2. • Changes in surface energy fluxes have impact on sea ice extent with its feedbacks. [ABSTRACT FROM AUTHOR]