In April of 2019, the New York City Council passed groundbreaking legislation capping the amount of greenhouse gases that large building owners can emit, or cause to be emitted, before heavy fines are imposed. The new law, known as Local Law 97 of 2019 (“Local Law 97”), holds great promise for reducing building energy use, which accounts for roughly forty percent of emissions across the globe and over two-thirds of emissions in New York City. However, it will also impose substantial costs on the local real estate industry. With an eye towards minimizing these costs, Local Law 97 calls on the City to conduct a study exploring the potential creation of an emissions trading program for regulated buildings. Trading programs have been successfully used for years in industrial sectors to reduce the administrative cost of emissions control, yet how to translate the lessons learned from industrial trading programs to buildings is still very much an open question. In this essay, I highlight some key points of distinction between the emissions trading program that New York City is contemplating and prior programs that policymakers will need to bear in mind as they develop a trading scheme for this novel context. As the federal government retreats from its efforts to tackle climate change, and the burden of doing so falls increasingly upon local leaders’ shoulders, the question of how to tailor emissions trading programs to the local landscape will doubtless be relevant for cities beyond New York. Because emissions trading programs, like other types of market-based environmental policies, are designed to lower the cost of achieving environmental goals, cities that successfully implement emissions trading programs may be able to tackle climate concerns more effectively.