The carbon neutrality target focuses on attaining net-zero CO 2 emissions, and does not specify non-CO 2 mitigation targets. While China’s ongoing policies regarding non-CO 2 GHGs do contribute to reductions in these emissions, such as Action p lan for methane emission control . In addition, existing studies provide valuable insights into China’s short-term non-CO 2 mitigation, but fall short in projecting long-term reductions and their uncertainties, as well as their contribution to future global warming in the context of China’s carbon neutrality. Beyond net-zero CO 2 , non-CO 2 GHGs are expected to play an increasingly crucial role in stringent, future China’s climate policy. However, it remains unclear to which degree a comprehensive GHG mitigation scheme that includes non-CO 2 GHG can affect the cost-effectiveness of mitigation efforts compared with CO 2 mitigation only, which is preventing a realistic roadmap of China’s long-term non-CO 2 mitigation.
By coupling the Global Change Analysis Model (GCAM) and the Model for the Assessment of Greenhouse Gas Induced Climate Change (MAGICC), this study projects China’s non-CO 2 mitigation potentials, costs and climate benefits by 2060. The findings could provide insights into the long-term non-CO 2 mitigation roadmaps and facilitate cost-effective GHG mitigation in China.
Results show that deep CH 4 mitigation in China will heavily rely on the synergistic effect of carbon neutrality through fuel switching and demand reduction. F-GHG emissions that are hardly affected by fuel switching show a substantial and persistent decline through the adoption of technical mitigation options. Even with corresponding mitigation measures, agriculture would remain the top emitter of China’s non-CO 2 , with its share steadily increasing from 35% in 2020 to 62% in 2060. Further non-CO 2 reductions call for technological innovation and structural change or behavior change. The cumulative non-CO 2 mitigation costs from 2020 to 2060 are even less than 10% of cumulative net-zero CO 2 costs. Most importantly, the climate benefit of non-CO 2 mitigation is 2.3-4.3 times that of CO 2 mitigation in terms of mitigation cost per unit in 2060. As non-CO 2 mitigation costs are only equivalent to 7%-8% of China’s net-zero CO 2 costs, but the avoided warming of non-CO 2 technical mitigation is equal to 18%-30% of net-zero CO 2 . The results thus highlight that incorporating a wider suite of GHGs into climate change mitigation strategies can enhance the cost-effectiveness of mitigation efforts.
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Opportunities beyond net-zero CO 2 for cost-effective greenhouse gas mitigation in China
Science Bulletin