Any private entity with significant greenhouse gas (GHG) emissions could be identified in the next climate change lawsuit. Filed in 2004 by a coalition of states and land trusts, Connecticut v. American Electric Power was the first major climate change lawsuit identifying private entities as defendants. On September 21, 2009, the U.S. Court of Appeals for the Second Circuit in Connecticut permitted plaintiffs to seek an order capping the carbon dioxide (CO2) emissions of five electric utilities by certain percentages for at least 10 years. Less than a month later, the U.S. Court of Appeals for the Fifth Circuit in Comer v. Murphy Oil held that a group of private-property owners could proceed with global warming claims against energy, fossil fuel, and chemical industries for causing Hurricane Katrina. The political question doctrine, which rescued the GHG-emitting defendants in the lower district courts, was rejected by both circuit courts, and may be dead. As a result, the ghost of Helen Palsgraf may have found some new defendants to haunt.

Helen Palsgraf's lawsuit in the early 1920s is one of the most famous American tort cases of all time. A man was running late trying to catch a train. He was carrying a package when, in the process of trying to board the train, he lost his balance. A guard on the platform, trying to help, pushed him from behind. In the process, the man dropped the package, which contained fireworks, causing an explosion when it hit the tracks. The shock of the explosion caused some scales many feet away at the end of the platform to fall--one of which fell on Mrs. Palsgraf and injured her. In a 4-3 opinion, the court held that while the guard may have been negligent in relation to the man carrying the package, he owed no duty of care to Mrs. Palsgraf because she was outside the "zone of danger." Both Connecticut and Comer imply a significant expansion of the Palsgraf majority decision's "zone of danger" rule.