HKS Authors

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Teresa and John Heinz Professor of the Practice of Environmental Policy


The Paris Agreement of 2015 uses Nationally Determined Contributions (NDCs) to achieve its goal to limit climate change to well below 2°C. Article 6 allows countries to cooperatively implement NDCs provided they do not double-count mitigation. We estimate that economic efficiency gains from cooperative implementation of existing NDC goals using Article 6 could reduce the cost of achieving NDC goals in 2030 to all parties by ~$300×10^9, which if reinvested in additional emissions mitigation could add 9 billion tons CO2/year mitigation, beyond the 8 billion tons CO2/year currently pledged in 2030. We estimate that more than half of the 2030 gains could come from nature-based measures, but long-term potential for nature-based measures is more limited. How much or even if this economic potential can be realized is uncertain and will depend on both the rules and their implementation.


Edmonds, James, Sha Yu, Haewon Mcjeon, Dirk Forrister, Joseph Aldy, Nathan Hultman, Ryna Cui, Stephanie Waldhoff, Leon Clarke, Stefano de Clara, and Clayton Munnings. "How much could article 6 enhance nationally determined contribution ambition toward paris agreement goals through economic efficiency?" Climate Change Economics 12.2 (2021).