With the federal government’s U-turn on climate policy, states are taking the lead in regulating greenhouse gas emissions. Specifically, carbon trading is gaining traction as more jurisdictions are joining cap-and-trade markets.The two regional blocs in the U.S., California, Quebec, and Ontario’s cap-and-trade system and the Regional Greenhouse Gas Initiative (RGGI) involving nine Northeastern states, recently outlined their plans after 2020 ending uncertainty about their medium-term future.