Long-term growth impact of climate change and policies: the Advanced Climate Change Long-term (ACCL) scenario building model

This paper provides a tool to build climate change scenarios to forecast Gross Domestic Product (GDP), modelling both GDP damage due to climate change and the GDP impact of mitigating measures. It adopts a supply-side, long-term view, with 2060 and 2100 horizons. It is a global projection tool (30 countries / regions), with assumptions and results both at the world and the country / regional level. This scenario exercise illustrates both the “tragedy of the horizon”, as gains from avoided climate change damage net of damage from mitigating policies are negative in the medium-term and positive in the long-term, and the “tragedy of the commons”, as climate change damage is widely dispersed and particularly severe in developing economies, while mitigating policies should be implemented in all countries, especially in advanced countries modestly affected by climate change but with large CO2 emission contributions.