Biological and Environmental Research - Earth and Environmental System Sciences
Earth and Environmental System Modeling

Black Carbon Increases Frequency of Extreme ENSO Events

TitleBlack Carbon Increases Frequency of Extreme ENSO Events
Publication TypeJournal Article
Year of Publication2019
JournalJournal of Climate
Volume32
Number23
Pages8323-8333
Abstract / Summary

El Niño–Southern Oscillation (ENSO) is the leading mode of Earth’s climate variability at interannual time scales with profound ecological and societal impacts, and it is projected to intensify in many climate models as the climate warms under the forcing of increasing CO2 concentration. Since the preindustrial era, black carbon (BC) emissions have substantially increased in the Northern Hemisphere. But how BC aerosol forcing may influence the occurrence of the extreme ENSO events has rarely been investigated. In this study, using simulations of a global climate model, we show that increases in BC emissions from both the midlatitudes and Arctic weaken latitudinal temperature gradients and northward heat transport, decrease tropical energy divergence, and increase sea surface temperature over the tropical oceans, with a surprising consequential increase in the frequency of extreme ENSO events. A corollary of this study is that reducing BC emissions might serve to mitigate the possible increasing frequency of extreme ENSO events under greenhouse warming if the modeling result can be translated into the climate in reality.

URLhttp://dx.doi.org/10.1175/jcli-d-19-0549.1
DOI10.1175/jcli-d-19-0549.1
Journal: Journal of Climate
Year of Publication: 2019
Volume: 32
Number: 23
Pages: 8323-8333
Publication Date: 12/2019

El Niño–Southern Oscillation (ENSO) is the leading mode of Earth’s climate variability at interannual time scales with profound ecological and societal impacts, and it is projected to intensify in many climate models as the climate warms under the forcing of increasing CO2 concentration. Since the preindustrial era, black carbon (BC) emissions have substantially increased in the Northern Hemisphere. But how BC aerosol forcing may influence the occurrence of the extreme ENSO events has rarely been investigated. In this study, using simulations of a global climate model, we show that increases in BC emissions from both the midlatitudes and Arctic weaken latitudinal temperature gradients and northward heat transport, decrease tropical energy divergence, and increase sea surface temperature over the tropical oceans, with a surprising consequential increase in the frequency of extreme ENSO events. A corollary of this study is that reducing BC emissions might serve to mitigate the possible increasing frequency of extreme ENSO events under greenhouse warming if the modeling result can be translated into the climate in reality.

DOI: 10.1175/jcli-d-19-0549.1
Citation:
Lou, S, Y Yang, H Wang, J Lu, S Smith, F Liu, and P Rasch.  2019.  "Black Carbon Increases Frequency of Extreme ENSO Events."  Journal of Climate 32(23): 8323-8333.  https://doi.org/10.1175/jcli-d-19-0549.1.