carbon trading
noun [ U ]
ukus(also carbon emissions trading) ENVIRONMENT
a system for buying and selling the right to release carbon dioxide into the environment. Companies or countries agree a limit on the amount of carbon dioxide that can be produced, then can buy the right to produce more than this from companies or countries that produce less:
If we can come up with some good market mechanisms, carbon trading has a lot of promise.
a carbon trading system/market/mechanism