Massachusetts et al. v. Environmental Protection Agency et al.

The case dealt with questions related to climate change and emissions regulations. The court had to decide whether the US Environment Protection Agency (EPA) was obliged to begin regulating the emission of four “greenhouse gases” under the Clean Air Act, which required that EPA should prescribe standards for the emissions of new motor vehicles in case of a danger for public health or welfare. EPA refused to regulate, stating that a casual link between greenhouse gases and the increase of global temperatures was not un-equivocally established. The Supreme Court held that, inter alia, the petitioner State of Massachusetts had standing to challenge EPA’s denial to regulate emissions. Congress had ordered EPA to protect Massachusetts and EPA’s refusal to regulate greenhouse gas emissions presented a risk of harm to the State that was both “actual” and “imminent”. Global sea levels had already begun to swallow Massachusetts coastal land as a result of global warming. The court emphasized that agencies did not generally resolve massive problems in one fell swoop, but instead refined their approach over time. While regulating motor-vehicle emissions would not itself reverse global warming, it would slow the pace of global emissions increases, no matter if other developing countries would increase their emissions. Finally, the court stressed that EPA could not avoid its statutory obligation by noting the uncertainty surrounding various features of climate change and concluding that it would therefore be better not to regulate at this time. It held that EPA had rejected the rule-making petition based on impermissible considerations. The case was reversed and remanded.