Dependence of economic impacts of climate change on anthropogenically directed pathways

There are great uncertainties in the projected economic impacts of climate change(1), arising from uncertainties in the climate response(2), the climate change mitigation pathway(3) and the socioeconomic development pathway(4). Although the relative contributions of these factors are important for climate change related decision-making, they are poorly understood. Here, we show to what extent the projected economic impacts of climate change can be attributed to these three factors. Our modelling framework consisting of global, multisectoral impact models coupled with an integrated assessment model enables us to estimate the global total economic impacts of climate change while incorporating these uncertainty sources. Whereas the most pessimistic pathway without mitigation would result in a net economic impact equivalent to 6.6% (3.9-8.6%) of global gross domestic product at the end of this century, the pathways with stringent mitigation would limit the impact to around or less than 1%. Although the uncertainties are great, the climate change mitigation pathway is the dominant factor and socioeconomic developments can also contribute to alleviate the impacts of climate change. These results suggest that decisions on mitigation and development have a great influence in determining the economic impacts of climate change, regardless of the uncertainties in the climate response.