Jessica Green's admonition to avoid linking carbon markets is not the consensus among economists and social scientists (Nature 543, 484–486; 2017). This advice seems to misinterpret how carbon-pricing instruments operate.

International trade in goods and services has improved welfare without a central authority to manage quantities and prices. In the same way, a central carbon bank is not a necessary condition for a system of linked carbon markets to achieve their objective of restricting emissions to the selected cap at the lowest possible cost. That said, an institution similar to the World Trade Organization could be useful for addressing market failures, to provide a forum for negotiations and to resolve disputes.

In our view, Green's one-size-fits-all claim that no carbon markets should be linked is too extreme, just as a recommendation to link all carbon markets would be. We need instead to accrue theoretical and empirical evidence for the extra benefits and costs engendered by linking previously isolated carbon markets (see, for example, B. Doda and L. Taschini J. Assoc. Environ. Resour. Econ. http://doi.org/b5pr; 2016).