Mitigation of China's carbon neutrality to global warming

Projecting mitigations of carbon neutrality from individual countries in relation to future global warming is of great importance for depicting national climate responsibility but is poorly quantified. Here, we show that China's carbon neutrality (CNCN) can individually mitigate global warming by 0.48 °C and 0.40 °C, which account for 14% and 9% of the global warming over the long term under the shared socioeconomic pathway (SSP) 3-7.0 and 5-8.5 scenarios, respectively. Further incorporating changes in CH4 and N2O emissions in association with CNCN together will alleviate global warming by 0.21 °C and 0.32 °C for SSP1-2.6 and SSP2-4.5 over the long term, and even by 0.18 °C for SSP2-4.5 over the mid-term, but no significant impacts are shown for all SSPs in the near term. Divergent responses in alleviated warming are seen at regional scales. The results provide a useful reference for the global stocktake, which assesses the collective progress towards the climate goals of the Paris Agreement. Global warming since the preindustrial era has been primarily attributed to the increase in atmospheric CO2 concentrations, which mainly results from the carbon emissions of fossil fuel combustion. The likely range of the total human-caused global surface temperature increase from 1850-1900 to 2010-2019 is 0.8 °C to 1.3 °C, with a best estimate of 1.07 °C. If worldwide carbon emissions continue at the current rate, global warming is likely to exceed 1.5 °C between 2030 and 2052, and even more than 3–5 °C at the end of the 21st century. To limit the increase in global mean temperature below 1.5 °C above preindustrial levels, reaching net zero of global CO2 emissions in 2055 and limiting non-CO2 greenhouse gas emissions after 2030 are crucial mitigation strategies. As one of the large annual emitters of CO2 emissions, China has committed to peak its carbon emissions before 2030 and attain carbon neutrality before 2060. A recent study based on a very simplified climate model reported that China's carbon neutrality alone will contribute a 0.16–0.21 °C avoided global warming at the end of the 21st century. However, the magnitude of such mitigation has not yet been quantified using a fully coupled Earth system model that incorporates all crucial components of the climate system.

Longhui Li, Yue Zhang, Tianjun Zhou, Kaicun Wang, Can Wang, Tao Wang, Linwang Yuan, Kangxin An, Chenghu Zhou, Guonian Lü