PNNL

Abstract

The 2015 Paris Agreement culminates a six-year transition toward a pledge and review international climate policy architecture. Parties will submit national pledges every five years, and an important policy task will be to assess and compare these contributions. In this paper, we discuss the case for economic analysis to produce comparability metrics for the assessment of pledges and outcomes. We use four integrated assessment models to produce such metrics of Paris Agreement pledges. Here we show differentiated effort across countries: wealthier countries pledge to undertake greater emission reductions with higher costs. The pledges fall in the lower end of the distributions of the social cost of carbon (SCC) and the cost-minimizing path to limiting warming to 2°C, suggesting a lack of global ambition. Countries’ marginal abatement costs vary by two orders of magnitude, illustrating large efficiency gains available through joint mitigation efforts. Marginal costs rise almost proportionally with income, but full policy costs reveal more complex regional patterns due to terms of trade effects. This work illustrates potential applications of integrated assessment models to inform the emerging Paris transparency regime.