Uncertainty in emissions projections for climate models

Abstract

Future global climate projections are subject to large uncertainties. Major sources of this uncertainty are projections of anthropogenic emissions. We evaluate the uncertainty in future anthropogenic emissions using a computable general equilibrium model of the world economy. Results are simulated through 2100 for carbon dioxide (CO₂), methane (CH4), nitrous oxide (N₂O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulfur hexafluoride (SF6), sulfur dioxide (SO₂), black carbon (BC) and organic carbon (OC), nitrogen oxides (NOx), carbon monoxide (CO), ammonia (NH3) and non-methane volatile organic compounds (NMVOCs). We construct mean and upper and lower 95% emissions scenarios (available from the authors at 1 degree by 1 degree latitude-longitude grid). Using the MIT Integrated Global System Model (IGSM), we find a temperature change range in 2100 of 0.9 to 4.0 degrees C, compared with the Intergovernmental Panel on Climate Change emissions scenarios that result in a range of 1.3 to 3.6 degrees C when simulated through MIT IGSM.