During the Clean Air Act era, were lawmakers aware of the role of fossil fuels in climate change?

How much was known about the dangers of human-induced climate change in the mid-20th century? Much more than most Americans think.

In a new paper published in Ecological Law QuarterlyNaomi Oreskes and a team of science historians detail more than a century of research linking carbon dioxide emissions to rising global temperatures.

The findings shed light on what Congress knew and intended when it targeted “air pollution” in the 1970 Clean Air Act — a question that has come up in the wake of a landmark 2022 Supreme Court case that limits federal agencies’ power to enforce the law.

“We have uncovered a huge amount of scientific work that had been lost, forgotten or buried,” said Oreskes, the Henry Charles Lee Professor of the History of Science.

Oreskes hopes the paper will be the definitive document explaining what was understood in the 1950s and ’60s about the dangers of burning fossil fuels. The 124-page paper covers everything from government reports on “unintended weather modification” to lawmakers long ago pondering the future of electric cars. The paper is a testament to how experts at the time viewed CO2.₂ as one of many environmental threats to be regulated.

“Today, we think of climate science and air pollution as separate things,” says co-author Colleen Lanier Christensen (PhD ’23), a postdoctoral researcher in the history of science, “but in the ’60s, the two were very closely intertwined.”

Oreskes began researching the topic about a decade ago at the request of Jody Freeman, the Archibald Cox Professor of Environmental Law at Harvard Law School, but the project took on more urgency after the Supreme Court’s West Virginia v. EPA decision limited the agency’s power to regulate carbon emissions from power plants, a major contributor to global warming.

The majority opinion, written by Chief Justice John Roberts, relied on a “practical understanding of legislative intent” and concluded that if the framers of the 1970 law intended to regulate COs, they would have taken a more direct approach.₂.

“The Supreme Court was basically asking a historical question,” Lanier-Christensen said, “but none of the justices actually looked historically at what Congress intended in passing the Clean Air Act.”

Irish physicist John Tyndall first described the heat-trapping effect of greenhouse gases around 1859. In the late 19th century, Swedish Nobel Prize-winning chemist Svante Arrhenius linked atmospheric carbon dioxide concentrations to the burning of fossil fuels. In 1896, he calculated that atmospheric CO₂ If concentrations are high, the planet would warm by 1.5 to 4.5 degrees Celsius.

In the 1930s, British engineer Guy Stewart Callender began collecting data on atmospheric CO.₂ In a paper published in 1940, CO₂ the amount of coal and oil that is known to have been burned, and from there, CO₂ For several years the effect on climate was called the “Calendar effect.”

American scientists looked into this issue in the 1950s, when physicist Gilbert Plath (Class of 1941) argued that rising temperatures were related to human activity. The New York Times featured Plath’s work in a 1953 article headlined “Industry May Change the Climate.”

By the early 1960s, Callender was complaining that “everyone liked to ‘take’ this problem,” including the community of scientists working for the US government, led by Alvin Weinberg, director of the Oak Ridge National Laboratory in Tennessee. In 1961, Weinberg gave a lecture on “Atmospheric Deterioration from the Accumulation of Carbon Dioxide.”₂At the University of Tennessee Science Fair.

“This wasn’t a super technical meeting,” stressed Oreskes, author of “The Big Myth” (2023) and the best-selling “Merchants of Doubt” (2010). “He understood that this was an issue that ordinary Americans needed to know about.”

And as the decade wore on, more and more ordinary Americans were finding out: In 1958, “It’s a Wonderful Life” director Frank Capra’s documentary, seen by millions of American schoolchildren by the mid-1960s, warned that “through the waste products of our civilization, mankind may be unwittingly changing the world’s climate.”

Also influential was poet Allen Ginsberg’s appearance on “The Merv Griffin Show” in February 1969. Ginsberg upset audiences by arguing that “the current rate of air pollution brought about by the proliferation of automobiles and their waste” could cause “a rapid buildup of heat on the planet.”

In response, one perplexed constituent wrote a letter to Senator Henry “Scoop” Jackson of Washington, who was a two-time Democratic presidential candidate and forwarded the letter to physicist Lee DuBridge, who served as science adviser to President Richard M. Nixon.

Dubridge’s response to Jackson detailed the increase in CO.₂ levels and the “greenhouse effect.” Later this year, DuBridge will return to these points on NBC’s “Meet the Press.”

To unearth this history, the study’s co-authors combed through 12 archives. “The challenge is that we’re looking at a period before 1970, before the EPA existed,” explained Lanier Christensen. “All environmental functions were decentralized across the federal government.”

A natural stop was Bates College, home to the archives of Maine Senator Edmund S. Muskie, the architect of the 1970 Clean Air Act.

“It’s how closely Senator Muskie and his office are following these issues. [1967] “The Secretary of Commerce’s report, ‘Motor Vehicles and Air Pollution,’ was used to communicate directly with scientists,” Lanier Christensen noted.

Fast forward to the 21st century, and much of this history has been forgotten, the researchers say. They argue that the U.S. Supreme Court got it wrong in West Virginia v. EPA, and point to an error it also made in the 2007 decision in Massachusetts v. EPA, which initially gave the EPA the power to regulate CO2.₂ As a pollutant covered by the 1970 Clean Air Act.

The court saw this as an unintended consequence of an intentionally broad law, with the late Justice John Paul Stevens writing that “at the time Congress enacted these provisions, research into climate change was in its infancy.”

“When I read that line, I nearly had a heart attack,” Oleskus recalled. “It was so, so incredibly wrong.”

As she says, the researcher’s almost book-like paper is CO₂ Prior to 1970, air pollution was recognized as both a pollutant and a threat to the Earth’s climate. Eventually, Muskie introduced the Clean Air Act on the Senate floor, warning that unchecked air pollution “could cause irreversible changes in our atmosphere and climate.”

But the paper “only tells the first half of the story,” Oreskes said. A second publication, still in preparation, will focus entirely on testimony to Congress before the bill was passed, further strengthening the co-authors’ argument that lawmakers intended to regulate CO.₂.

“I don’t expect the judge to read these documents and change his mind,” Oreskes said, “but what he can do is empower the lawyers who are trying these cases to refute the false allegations.”