Person:

Aldy, Joseph

The pollution haven hypothesis suggests that unilateral domestic emission mitigation policies could cause adverse “competitiveness” impacts on domestic manufacturers as they lose market share to foreign competitors and relocate production activity – and emissions – to unregulated economies. We construct a precise definition of competitiveness impacts appropriate for climate change regulation that can be estimated exclusively with domestic production and net import data. We use this definition and a 20+ year panel of 400+ U.S. manufacturing industries to estimate the effects of energy prices, which is in turn used to simulate the impacts of carbon pricing policy. We find that a U.S.-only $15 per ton CO2 price will cause competitiveness effects on the order of a 1.0 to 1.3 percent decline in production among the most energy-intensive manufacturing industries. This amounts to roughly one-third of the total impact of a carbon pricing policy on these firms’ economic output.

The availability of practical mechanisms for comparing domestic efforts aimed at mitigating global climate change are important for the stability, equity, and efficiency of international climate agreements. We examine a variety of metrics that could be used to compare countries’ climate change mitigation efforts and illustrate their potential application to large developed and developing countries. Because there is no single comprehensive, measurable metric that could be applied to all countries, we suggest using a set of indicators to characterize and compare mitigation effort, akin to using a set of economic statistics to indicate the health of the macroeconomy. Given the iterative pledge and review approach that is emerging in the current climate change negotiations, participation, commitment, and compliance could be enhanced if this set of indicators is able to show that all parties are doing their “fair share,” both prospectively and retrospectively. The latter, in particular, highlights the need for a well-functioning policy surveillance regime.

The Paris Agreement culminates a six-year transition toward an international climate policy architecture based on parties submitting national pledges every five years. An important policy task will be to assess and compare these contributions. We use four integrated assessment models to produce metrics of Paris Agreement pledges, and 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 2⁰C, suggesting insufficient global ambition in light of leaders’ climate goals. Countries’ marginal abatement costs vary by two orders of magnitude, illustrating that large efficiency gains are available through joint mitigation efforts and/or carbon price coordination. Marginal costs rise almost proportionally with income, but full policy costs reveal more complex regional patterns due to terms of trade effects.