Benchmark estimate of the effect of anthropogenic emissions on the ocean surface

• Published in: International Journal of Climatology
• Main Authors: Stone, Dáithí A., Pall, Pardeep
• Other Authors: Biological and Environmental Research, Ministry of Business, Innovation and Employment
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2021
• Subjects: Sea ice
• Online Access: http://dx.doi.org/10.1002/joc.7002; https://onlinelibrary.wiley.com/doi/pdf/10.1002/joc.7002; https://onlinelibrary.wiley.com/doi/full-xml/10.1002/joc.7002; https://rmets.onlinelibrary.wiley.com/doi/am-pdf/10.1002/joc.7002; https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/joc.7002

Abstract Investigations into the role of anthropogenic emissions in the occurrence of extreme weather often use a method that compares simulations of atmospheric climate models run under a factual scenario of historical boundary conditions observed during the period of the event against simulations run under a counterfactual scenario of what those boundary conditions might naturally have been over that same period in the absence of anthropogenic emissions. A particular requirement for this experiment design is an accurate estimation of ocean surface boundary conditions for use by the counterfactual natural simulations. Here we use output from the CMIP5 multi‐climate‐model archive to develop a robust estimate of sea surface temperatures and sea ice conditions for use in counterfactual natural simulations, intended as a benchmark estimate to facilitate comparison across climate models and across studies. This development includes tests to ensure that the final estimate is stable from year‐to‐year and stable against other perturbations to the methodology, as well as consideration of the strengths and weaknesses in comparison to other available attributable warming estimates. While this estimate is tailored specifically for the International CLIVAR C20C+ Detection and Attribution Project, it can be used by related projects as well.