The Social Cost of CO2 from the PAGE09 Model

A new version of the PAGE integrated assessment model, PAGE09, is introduced. The mostimportant scientific, impact, emission and adaptation inputs in the latest default version of themodel, PAGE09 v1.7 are described. The scientific and economic impact results are presented for abusiness as usual (BAU) emissions scenario, and for a low emissions scenario which aims to have a50% chance of keeping the rise in global mean temperatures below 2 degC. Today’s mean social costof CO2 is about $100 per tonne of CO2 in the BAU scenario, and about $50 per tonne in the lowemissions scenario. The major influences on the SCCO2 are found to be the transient climateresponse, the pure time preference rate, the elasticity of the marginal utility of consumption, thefeedback response time of the earth and the weight on non‐economic impacts...