American Electric Power Co. v. Connecticut

Several U.S. states, land trusts, and New York City filed suit against some of the United States' largest electric power companies over their greenhouse gas emissions. The plaintiffs claimed public nuisance caused by the defendants' contributions to climate change.

The United States Supreme Court ultimately ruled that corporations can't be sued for greenhouse gas emissions under federal common law because regulation of greenhouse gases rested in the United States Environmental Protection Agency in accordance with the Clean Air Act.

Background
In 2004, eight U.S. states, three land trusts, and New York City filed a public nuisance claim against the nation's largest electric power generators, claiming that their contributions to climate change constituted a public nuisance. The case was initially dismissed by the Southern District of New York but the Second Circuit Court said it could continue. The power companies applied for a writ of certiorari which was granted.

As the case made its way through the courts, the U.S. Supreme Court had ruled in the landmark case Massachusetts v. EPA that the Clean Air Act granted the United States Environmental Protection agency the authority to regulate greenhouse gas emissions.

Relevant Laws and Principles

 * Political Question Doctrine
 * Public Nuisance
 * Clean Air Act

Ruling
The U.S. Supreme Court ruled 8-0 that common law in the area had been displaced by the Clean Air Act and that the regulation of greenhouse gases was now up to the United States Environmental Protection Agency. The ruling reinforced the decision made several years earlier in Massachusetts v. EPA.

Takeaways
The decision confirms the United States Environmental Protection Agency as the regulator of greenhouse gas emissions but also limits the ability to sue corporations for their greenhouse gas emissions. The case set a precedent that was used to dismiss other cases of climate litigation, notably Kivalina v. ExxonMobil.

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