China\u2019s Non-CO2 Greenhouse Gas Emissions: Future Trajectories and Mitigation Options and Potential

Nina Khanna,Fei Teng,Xu Liu,Xin Wang,Jiang Lin

doi:10.1038/s41598-019-52653-0

Abstract

Forecasts indicate that China’s non-carbon dioxide (CO2) greenhouse gas (GHG) emissions will increase rapidly from the 2014 baseline of 2 billion metric tons of CO2 equivalent (CO2e). Previous studies of the potential for mitigating non-CO2 GHG emissions in China have focused on timeframes through only 2030, or only on certain sectors or gases. This study uses a novel bottom-up end-use model to estimate mitigation of China’s non-CO2 GHGs under a Mitigation Scenario whereby today’s cost-effective and technologically feasible CO2 and non-CO2 mitigation measures are deployed through 2050. The study determines that future non-CO2 GHG emissions are driven largely by industrial and agricultural sources and that China could reduce those emissions by 47% by 2050 while enabling total GHG emissions to peak by 2023. Except for F-gas mitigation, few national or sectoral policies have focused on reducing non-CO2 GHGs. Policy, market, and other institutional support are needed to realize the cost-effective mitigation potentials identified in this study.

Highlights

China is already the world’s largest energy consumer and largest emitter of energy-related carbon dioxide (CO2)[1,2], and is the world’s largest emitter of non-CO2 greenhouse gases (GHGs) emissions[3]
This study shows that adopting today’s cost-effective CO2 and non-CO2 GHG mitigation measures will enable China’s total GHG emissions to peak earlier at a lesser amount
The CO2 Plus Non-CO2 GHG Mitigation Scenario peaks at 12.3 billion metric tons (Bt) CO2 equivalent (CO2e) in 2023, whereas in the Reference Scenario total GHG emissions peak at 17.0 Bt CO2e in 2036 (Fig. 1a). (Unless stated otherwise, results for the 100-year global warming potential (GWP) are based on the 2006 Intergovernmental Panel on Climate Change (IPCC) Guidelines for Global Warming Potentials, which is the most widely adopted GHG reporting convention in the United States)

Summary

Introduction

China is already the world’s largest energy consumer and largest emitter of energy-related carbon dioxide (CO2)[1,2], and is the world’s largest emitter of non-CO2 greenhouse gases (GHGs) emissions (excluding those related to land-use changes and forestry)[3]. Recent studies emphasize the importance of reducing short-lived climate pollutants (including non-CO2 GHGs such as methane and some F-gases) —in addition to significantly reducing CO2 emissions—in order to achieve the overall goal of limiting global temperature increase to less than 2 °C8,9. The recent Intergovernmental Panel on Climate Change (IPCC) report points out the importance of concurrent deep reductions in non-CO2 GHG emissions, especially methane, along with net zero CO2 emissions to limiting global warming to 1.5 °C12. Previous research has identified significant potential for reducing non-CO2 GHGs in China, but large uncertainties remain. In China, data challenges and lack of awareness have hampered research on the growth and mitigation of non-CO2 GHG emissions, adding to the uncertainties.

Methods

Results

Discussion

Conclusion