Border Adjustments Supplementing Nationally Determined Carbon Pricing

As agreed on in the Paris Agreement, each country determines its own contribution to combat climate change on a voluntary basis. There is no mechanism to force a country to comply with its own nationally determined contributions. This bottom-up approach builds on unilateral actions and yields a kind of carbon pricing, which is not necessarily identical across countries. As a consequence, these nationally determined climate policies have drawbacks in terms of carbon leakage and loss of competitiveness for firms producing in high carbon price countries. To reduce these negative effects, border adjustments (BAs) may be appropriate subsequent to more stringent environmental regulation. We model a three-stage game involving carbon price competition in the first stage, the introduction of BAs in the second stage and oligopolistic competition between firms in the third stage. Strategic trade theory suggests that the qualitative results about the optimal BA policy may vary with the underlying type of competition, namely Bertrand and Cournot competition. However, our results are similar for both types of competition. We conclude that BAs are suitable for supporting a more stringent environmental policy. Moreover, we find that anticipation of the implementation of BAs in the second stage yields higher average carbon prices in the first stage since high carbon price countries increase their carbon prices whereas the other countries partially offset.