Stabilizing climate change well below 2 °C and towards 1.5 °C requires comprehensive mitigation of all greenhouse gases (GHG), including both CO2 and non-CO2 GHG emissions. This study incorporates the latest global non-CO2 emissions and mitigation data into the GCAM integrated assessment model and examines 90 mitigation scenarios pairing different levels of CO2 and non-CO2 GHG abatement pathways. The findings suggest that without full implementation of non-CO2 mitigation, net-zero CO2 must be achieved about two decades earlier. Conversely, comprehensive GHG abatement integrating non-CO2 measures alongside net-zero CO2 commitment can help achieve 1.5 °C stabilization. Decarbonization-driven fuel switching primarily reduces non-CO2 emissions from fuel extraction and end-use, while targeted non-CO2 mitigation significantly reduces fluorinated gas emissions from industrial processes and cooling sectors. The integrated modeling provides insights into how system-wide GHG mitigation affects the timing of net-zero CO2 for 1.5 °C and 2 °C scenarios.

Yang Ou, Christopher Roney, Jameel Alsalam, Katherine Calvin, Jared Creason, Jae Edmonds, Allen A. Fawcett, Page Kyle, Kanishka Narayan, Patrick O’Rourke, Pralit Patel, Shaun Ragnauth, Steven J. Smith, Haewon McJeon