Integrating non-CO2 options into mitigation strategies could enhance China’s climatic cost benefits of emission reductions

The carbon neutrality target focuses on attaining net-zero CO₂ emissions, and does not specify non-CO₂ mitigation targets. While China’s ongoing policies regarding non-CO₂ GHGs do contribute to reductions in these emissions, such as Action plan for methane emission control. In addition, existing studies provide valuable insights into China’s short-term non-CO₂ 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 CO₂, non-CO₂ 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-CO₂ GHG can affect the cost-effectiveness of mitigation efforts compared with CO₂ mitigation only, which is preventing a realistic roadmap of China’s long-term non-CO₂ 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-CO₂ mitigation potentials, costs and climate benefits by 2060. The findings could provide insights into the long-term non-CO₂ mitigation roadmaps and facilitate cost-effective GHG mitigation in China.

Results show that deep CH₄ 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-CO₂, with its share steadily increasing from 35% in 2020 to 62% in 2060. Further non-CO₂ reductions call for technological innovation and structural change or behavior change. The cumulative non-CO₂ mitigation costs from 2020 to 2060 are even less than 10% of cumulative net-zero CO₂ costs. Most importantly, the climate benefit of non-CO₂ mitigation is 2.3-4.3 times that of CO₂ mitigation in terms of mitigation cost per unit in 2060. As non-CO₂ mitigation costs are only equivalent to 7%-8% of China’s net-zero CO₂ costs, but the avoided warming of non-CO₂ technical mitigation is equal to 18%-30% of net-zero CO₂. The results thus highlight that incorporating a wider suite of GHGs into climate change mitigation strategies can enhance the cost-effectiveness of mitigation efforts.

 

See the article:

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

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