People downloaded this landmark climate study 1 million times

Around 15 years ago, Naomi Oreskes, a historian of science, observed that many reporters repeatedly covered climate change in a puzzling way.

The popular media wrote about the topic as if there was still "a great debate" about whether human-caused climate change was occurring, said Oreskes, now a professor of the history of science at Harvard University. But among the atmospheric scientists, geologists, and oceanographers actively researching and publishing peer-reviewed research on the topic, there was no debate.

"None of the scientists I knew, working in the area, thought there was any doubt that man-made climate change was underway," Oreskes recalled.

To test her hypothesis -- that no such academic debate existed -- Oreskes analyzed 928 relevant abstracts published in scientific journalists between 1993 and 2003, all containing the keywords "climate change." The results were stark: None -- zero -- of the studies disagreed with the climate consensus among climate researchers: that climate change was happening, and humans were the cause.

On Monday, Oreskes' decade and a half old study "The Scientific Consensus on Climate Change" surpassed 1 million downloads. Over time, interest in downloading the paper has not waned, as is the fate of many academic studies. Instead, the study has steadily accrued readers, noted John Cook, a research assistant professor at the Center for Climate Change Communication at George Mason University.

"It was the first scientific attempt to quantify the [climate] consensus," said Cook. "It was the first study to do that and help raise the public's awareness."

The conclusions are ever salient.

"I think it’s pretty clear that scientists were not, and are not wrong," said Oreskes. "Nearly all the predictions scientists made in the 1950s, '60s and '70s have come true. If there is any discrepancy, it is that many of the outcomes we are now observing are worse than predicted."

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The evidence abounds, all over the planet. Greenland -- with an ice sheet two and a half times the size of Texas -- experienced historic melting this summer. Glaciers everywhere are retreating. Southwestern states are now contending with unprecedented, wide-scale drought. Wildfires are raging in the Arctic. This June was the hottest June in 139 years of record-keeping. All-time heat records -- in countries with the oldest temperature records in the world -- have been dropping like flies.

By the late '90s, the climate consensus had been well established, explained Andrew Dessler, a professor of atmospheric sciences at Texas A&M University. It turned out that earlier scientists, like those who contributed to the legendary 1979 Charney Report, were spot on about an increase in carbon emissions resulting in a warming planet.

"They had all the basics right then," noted Dessler. Even in 1896, the Swedish scientist Svante Arrhenius had already established the fundamental relationship between rising CO2 and a changing climate, Dessler added.

So by 2004, then, the consensus among climate scientists -- who were actively researching the environmental issue -- was well-established. Oreskes just proved it. And she proved it by addressing a simple question: Is there a scientific consensus? "It goes to show that if you ask an interesting question, immortal fame will be yours -- you’ll get 1 million downloads," Dessler mused.

Since then, researchers analyzed thousands more studies to cement the climate consensus.

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Though, there will always be a vocal few denying the academic evidence. For example, just a "handful of papers" among nearly 12,000 that Cook analyzed denied the climate consensus, he said. But such will be the case for any scientific field.

"There's still a handful that deny plate tectonics," noted Cook. "Even 'flat earth' is making a comeback."

"I don't know how many scientists believe that," he added.

The few scientists who reject the climate consensus today are not climate scientists, emphasized Oreskes. They usually have a background in other fields, like nuclear physics and rocketry. A relevant example today is Princeton physicist and carbon dioxide-advocate William Happer, who now serves on President Trump's National Security Council. Happer, renowned for his work involving atomic collisions and telescope optics, doesn't simply reject the climate consensus; he asserts that Earth is in a "CO2 famine" and has concluded that "if plants could vote, they would vote for coal." Plant biologists, however, have thoroughly debunked Happer's outlandish claims.

The denial also lives on in organizations that are opposed to solutions for slashing carbon emissions and curbing fossil fuels. The Competitive Enterprise Institute, a think tank in Washington D.C. that avidly advocates for fossil fuel industry interests, sent a letter to NASA in July 2019, requesting that NASA remove online information about the climate consensus.

Today, reputable science is scrutinized by other scientists, the gold standard called "peer review," before being deemed suitable for publication in academic journals. Once published, the well-documented research is laid bare for further, everlasting scientific scrutiny. The climate consensus was born here, not in opinion pieces in newspapers nor by sensationalist TV commentators.

"True scientists debate in the halls of science, not Fox News or the Wall Street Journal, and true scientists honor evidence," said Oreskes. "This is what the deniers and rejectionists do: reject evidence. And now, 15 years after my original study, the evidence is utterly overwhelming.  As the [Intergovernmental Panel on Climate Change] has said, it is 'unequivocal.'"

"Anyone who denies that is, well, in denial."