Estimating a Climate Change Damage Function through General Equilibrium Modeling

A Climate Change Damage Function (CCDF) is a reduced form relationship linking macroeconomic aggregates (e.g., potential GDP) to climate indicators (e.g., average temperature levels). This function is used in a variety of studies about climate change impacts and policy analysis. However, despite the fact that this function is key in determining results in many integrated assessment models, it is not typically calibrated in a consistent and rigorous way. This paper presents a novel approach, in which several different impacts of climate change are first assessed by means of a full-fledged computable general equilibrium model of the world economy, then results are interpolated to get a simple relationship of the CCDF type. The estimated CCDF is compared with other popular functions used in the literature, to highlight the possible implications associated with the alternative adoption of this functional relationship.