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

Achieving net-zero CO emissions is the current main focus of China's carbon neutrality goal. However, non-CO greenhouse gases (GHGs) are more powerful climate forcers, making their emission reduction an opportunity to rapidly mitigate future warming. Here, we evaluate non-CO mitigation potentials, costs and climate benefits in the context of China's carbon neutrality goals. The assessment is conducted by coupling the integrated assessment model GCAM with a climate emulator. The findings indicate that mitigation technologies can largely reduce fluorinated gas emissions from industrial sectors, but long-term non-CO reductions of energy sector activities rely heavily on fuel switching. Furthermore, the cumulative costs of deploying non-CO mitigation technologies are projected to be less than 10 % of the total costs of achieving carbon neutrality from 2020 to 2060. If non-CO mitigation measures are included in the overall mitigation portfolio, the benefits of avoided warming would by far outweigh the total mitigation cost increase. Our results thus highlight that incorporating a wider suite of GHGs into climate change mitigation strategies can enhance the cost-effectiveness of mitigation efforts.