Potential carbon leakage under the Paris Agreement

Carbon leakage is the effect of emissions transferring to certain countries due to others having a stricter climate policy. This phenomenon is shown to have undercut the effectiveness of the Kyoto Protocol. Considering the increasingly globalised nature of the world economy, carbon leakage may have an even greater potential under the Paris Agreement some 15 years later. Although a more global approach to combatting climate change, the Paris Agreement is susceptible to leakage because of its lack of policy harmonization and enforcement mechanisms. Here, we perform the first quantitative analysis of the potential for carbon leakage under Paris, using the GTAP-E general equilibrium model of the world economy with energy and carbon emissions to analyse leakage effects under six scenarios. Two of these scenarios analyse regions implementing climate policy in isolation, two greater participation, but still not harmonized, global Paris Agreement policy, and a further two analyse the effect of a US withdrawal from the agreement. Both cases are considered with and without the US withdrawal. Our analysis demonstrates that there is potential for significant carbon leakage effects, in line with the rates produced from studies on the Kyoto Protocol. Depending on model elasticities, we find medium carbon leakage in the range of 1–9% (with a central estimate of 3–4%) under co-ordinated Paris Agreement policy across countries, compared to high leakage of 8–31% when countries operate in isolation. However, scenarios where the USA withdraws from the agreement result in roughly doubling of leakage rates, in the range of 3–16% (central estimate 7%), which demonstrates the vulnerability of the Paris Agreement in its current form. To limit leakage effects, greater policy co-ordination to achieve consistent implicit carbon prices is needed across countries.