Variability, timescales, and nonlinearity in climate responses to black carbon emissions

• Published in: Atmospheric Chemistry and Physics
• Main Authors: Yang, Yang, Smith, Steven J., Wang, Hailong, Mills, Catrin M., Rasch, Philip J.
• Language: unknown
• Published: 2023
• Subjects: 54 ENVIRONMENTAL SCIENCES; Arctic; black carbon
• Online Access: http://www.osti.gov/servlets/purl/1507400; https://www.osti.gov/biblio/1507400; https://doi.org/10.5194/acp-19-2405-2019

Black carbon (BC) particles exert a potentially large warming influence onthe Earth system. Reductions in BC emissions have attracted attention as apossible means to moderate near-term temperature changes. For the first time,we evaluate regional climate responses, nonlinearity, and short-termtransient responses to BC emission perturbations in the Arctic, midlatitudes,and globally based on a comprehensive set of emission-driven experimentsusing the Community Earth System Model (CESM). Surface temperature responsesto BC emissions are complex, with surface warming over land from midlatitudeBC perturbations partially offset by ocean cooling. Climate responses do notscale linearly with emissions. While stronger BC emission perturbations havea higher burden efficiency, their temperature sensitivity is lower. BCimpacts temperature much faster than greenhouse gas forcing, with transienttemperature responses in the Arctic and midlatitudes approaching aquasi-equilibrium state with a timescale of 2–3 years. We find largevariability in BC-induced climate changes due to background model noise. As aresult, removing present-day BC emissions results in discernible surfacetemperature changes for only limited regions of the globe. In order to betterunderstand the climatic impacts of BC emissions, both the drivers ofnonlinear responses and response variability need to be assessed acrossclimate models.