Last month, the Pennsylvania Supreme Court held that environmental groups could intervene in litigation to use the Environmental Rights Amendment of the Pennsylvania Constitution to support a regulation even though the Department of Environmental Protection had declined to make that argument. See Shirley v. Pennsylvania Legislation Reference Bureau, No. 85 MAP 2022 (Pa. July 18, 2024). Because the courts have not fleshed out all the nuances of what the Environmental Rights Amendment means, this superficially procedural decision may have important implications for how that constitutional jurisprudence develops.

The issue arose in litigation over the adoption in the last administration of a regulation by the Environmental Quality Board to establish a system of tradable carbon dioxide emission allowances for large electric powerplants that would have supported participation by Pennsylvania in the Regional Greenhouse Gas Initiative. 52 Pa. Bull. 2471 (Apr. 23, 2022), codified at 25 Pa. Code Sections 145.301 to .409. RGGI is a "cap-and-trade" agreement among several northeastern states intended to reduce the climate impact of their electricity sector. Under RGGI, powerplants require allowances to emit carbon dioxide; one allowance allows the emission of one ton in a year. Powerplant operators may purchase allowances at an auction from the state and may trade those allowances on a secondary market. In that way, the system creates a price for carbon emissions and, if the market works efficiently, that price should be set at the marginal cost of avoiding a ton of carbon emission by the emitter who can avoid that marginal emission at the lowest cost. Emissions reductions should therefore be achieved by the electricity sector at the lowest total cost.