Has Joint Implementation reduced GHG emissions? Lessons learned for the design of carbon market mechanisms

The analysis indicates that about three-quarters of JI offsets are unlikely to represent additional emissions reductions. This suggests that the use of JI offsets may have enabled global GHG emissions to be about 600 million metric tons of carbon dioxide equivalent higher than they would have been if countries had met their emissions domestically.

Of the six largest project types assessed in more detail, the authors find only one – N₂O abatement from nitric acid production – had overall high environmental integrity. The evaluation clearly shows that oversight of an international market mechanism by the host country alone is insufficient to ensure environmental integrity.

The paper makes recommendations for the ongoing review of the JI Guidelines, for carbon markets generally, and for a new climate agreement.