"Justice John Paul Stevens was one of the great environmental heroes of the last century," Washington Gov. and climate-focused presidential candidate Jay Inslee wrote in a statement following his death. "His decisions formed the bedrock of America's environmental laws, and his impact on our environment will be felt for generations to come."

Stevens was appointed to the court by President Gerald Ford in 1975 and retired in 2010 at the age of 90, having served more than twice the average amount of time for a Supreme Court Justice, the Associated Press reported. He was characterized as moving from the center to the liberal wing of the court during his tenure, but Stevens himself thought that was inaccurate. In his view, the court had moved to the right while his positions had stayed roughly the same.

"I don't think of myself as a liberal at all," Stevens told The New York Times in 2007, as the Associated Press reported. "I think as part of my general politics, I'm pretty darn conservative."

However, Stevens did rule in favor of a number of positions considered liberal, including gay rights, abortion rights and gun control, according to Reuters. He also opposed key Bush administration policies. For example, he wrote the court's decision that detainees at Guantanamo Bay could challenge their incarceration in U.S. courts.

Another disagreement with the Bush administration marked perhaps the cornerstone of his environmental legacy. In Massachusetts v. EPA, he wrote the majority opinion arguing that the U.S. Environmental Protection Agency (EPA) had the authority to regulate auto emissions that contribute to climate change, The New York Times reported at the time. Further, he ruled that, if the agency chose not to regulate greenhouse gases, it would have to justify its decision with science.

The Bush administration has argued that the EPA lacked the authority to regulate greenhouse gas emissions under the Clean Air Act and that, even if it had the power, the Bush EPA would not choose to use it. Stevens disagreed.

"Because greenhouse gases fit well within the Act's capacious definition of 'air pollutant,' EPA has statutory authority to regulate emission of such gases from new motor vehicles," Stevens wrote.

His decision paved the way for key Obama-era policies, such as the first auto-emissions standards focused on limiting climate-changing emissions, Grist wrote in a reflection on his retirement in 2010.

Manhattan v. EPA wasn't his only significant environmental decision. Grist highlighted three others:

1. Chevron v. NRDC: This 1984 decision was initially seen as a defeat for environmentalists because it said the DC Circuit could not override the Reagan EPA's decision to give more flexibility to companies in honoring their Clean Air Act obligations. However, it set an important precedent that the courts should defer to regulatory agencies when they act on a reasonable interpretation of a law.
2. Babbitt v. Sweet Home Chapter Of Communities For A Great Oregon: In this 1995 case, Stevens reinstated the portion of the Endangered Species Act that protected the habitats of endangered species. It had been struck down based on a narrow interpretation by the DC Circuit, but Stevens argued that the intent of the law was clearly on the side of protecting habitats.
3. Sierra Preservation Council v. Tahoe Regional Planning Agency: In this case, decided in 2002, Stevens wrote the majority opinion that upheld land use protections for Lake Tahoe. His ruling reversed the court's abuse of the Takings Clause of the Fifth Amendment to block environmental laws.

"Justice Stevens should be remembered as a great justice in environmental cases, not because he bent the law to favor environmental outcomes, but rather because he insisted that the law itself, which dictates environmental outcomes in many cases, be followed," Grist concluded.

Stevens died in a hospital in Fort Lauderdale, Florida following complications from a stroke he suffered on Monday, according to a Supreme Court statement reported by Reuters. He was remembered fondly by his former colleagues.

"He brought to our bench an inimitable blend of kindness, humility, wisdom, and independence. His unrelenting commitment to justice has left us a better nation," Chief Justice John Roberts said in the statement.

The Atlantic Coast Pipeline Fight Could Go to the Supreme Court https://t.co/PyjtlKV3vr

— Lakota Country Times (@Lakota_Timez) March 2, 2019