In the absence of strong federal climate action in the U.S., sub-national actors have been leading the charge to meet the targets of the Paris Climate Agreement. At the forefront of this effort is the joint cap-and-trade agreement between California and Quebec, report Alex Green and Robert Jackel of The Atlantic. Their innovative program is made possible through the Western Climate Initiative, Inc. – a private, non-profit corporation that provides administrative support without overstepping constitutional boundaries. It’s the only program in the world in which sub-national governments in different countries operate a carbon market.

More importantly, the Western Climate Initiative, Inc. provides a system that more states and provinces can join – and there is strong incentive to do so. A bigger, linked market increases the diversity of opportunities to reduce emissions and makes the overall system more efficient and more stable.