Which act was upheld by the US Supreme Court in 2007 for regulating GHG emissions?

The Clean Air Act is the legislation upheld by the US Supreme Court in 2007 for regulating greenhouse gas (GHG) emissions. This landmark decision confirmed the authority of the Environmental Protection Agency (EPA) to regulate GHG emissions under the Act, recognizing the dangers posed by these pollutants to public health and the environment.

The ruling emphasized the need for federal agencies to address climate change by regulating the emissions of gases that contribute to it. The case brought attention to the significance of the Clean Air Act as a crucial tool in federal environmental policy, particularly in lieu of increasing scientific evidence about the impacts of climate change.

In contrast, the other acts mentioned do not specifically address GHG emissions: the Clean Water Act focuses on regulating discharges into US waters, the Federal Insecticide, Fungicide, and Rodenticide Act regulates pesticide use, and the National Environmental Policy Act requires federal agencies to assess the environmental effects of their proposed actions. Thus, the significance of the Supreme Court's decision lies in the recognition of the Clean Air Act's role in tackling the pressing issue of climate change through the regulation of air pollutants, including greenhouse gases.