How Warming and Steric Sea Level Rise Relate to Cumulative Carbon Emissions After Many Centuries

Monday, 15 December 2014
Philip Goodwin, University of Southampton, Southampton, SO14, United Kingdom, Richard G Williams, University of Liverpool, Liverpool, L69, United Kingdom and Andy John Ridgwell, University of Bristol, Bristol, BS8, United Kingdom
Surface warming and steric sea level rise over the global ocean nearly linearly increase with cumulative carbon emissions for an atmosphere-ocean equilibrium, reached many centuries after emissions cease. Surface warming increases with cumulative emissions with a proportionality factor, ΔT2xCO2 /(IB ln 2), ranging from 0.8 to 1.9 K (1000 PgC)-1 for surface air temperature, depending on the climate sensitivity for a doubling of CO2, ΔT2xCO2 (in degrees K), and the buffered carbon inventory, IB (in Pg of carbon). Steric sea level rise similarly increases with cumulative emissions and depends on the climate sensitivity of the bulk ocean, ranging from 0.4 K to 2.7 K; a factor 0.4±0.2 smaller than that for surface temperature based on diagnostics of two Earth System models. The implied steric sea level rise ranges from 0.7 m to 5 m for a cumulative emission of 5000 PgC, approached perhaps 500 years or more after emissions cease.