Skip to main content

Sign up for our newsletter.

Quality journalism. Progressive values. Direct to your inbox.

A burned Valero gas station smolders during the Creek fire in an unincorporated area of Fresno County, California on September 08, 2020. (Photo: Josh Edelson/AFP via Getty Images)

A burned Valero gas station smolders during the Creek fire in an unincorporated area of Fresno County, California on September 08, 2020. (Photo: Josh Edelson/AFP via Getty Images) 

New Study Finds Planet Heading Toward Temperature Threshold Not Seen in 34 Million Years

Researchers behind the comprehensive study of Earth's atmospheric record over tens of million of years say "immediate and stringent action" could prevent the most dire outcomes.

Kenny Stancil

A newly published study conducted by a team of climate scientists warns that—barring prompt and rigorous efforts to minimize greenhouse gas emissions—"Earth is on track for some of the strongest, fastest climate change the planet has ever experienced."

Undertaking what Chelsea Harvey of Scientific American described as "one of the most comprehensive investigations of the Earth's climate history," the researchers used chemical analyses of ancient sediments to discern information about our planet's climatological record. 

The sediments—obtained by drilling the ocean floor in various locations around the world over the course of several years—contain "the preserved shells of tiny organisms that can tell scientists about the temperature and chemical composition of the ocean when they were formed," Harvey explained. 

Some of the sediments are 66 million years old, which enabled the research team to "reconstruct Earth's climate history going back to the mass extinction that killed three-quarters of the planet's species, including dinosaurs," Harvey reported. 

What the scientists found is that the planet has gone through four distinctive climate phases, which they label "warmhouse, hothouse, coolhouse, and icehouse states."

In general, transitions between climate states have hinged on changing concentrations of greenhouse gasses, typically generated by "volcanic eruptions and other natural processes," as well as "shifts in the Earth's orbit that affected the amount of solar energy reaching the planet," Scientific American noted.

Fifty million years ago, when Earth was in its hottest phases and long before the existence of humans, planetary temperatures were more than 10 degrees Celsius hotter than they are at present. However, reaching those temperatures took thousands or even millions of years, which is much different than the accelerated warming occurring today, warns the study, published in the journal Science

While the world has been in an icehouse state for millions of years, explained Harvey, "Earth could once again reach a temperature threshold not seen for at least 34 million years" in only a few centuries unless society limits greenhouse gas emissions. 

Prior to the industrial era, it would have taken thousands of years, at least, for such dramatic levels of warming to unfold. 

According to Jim Zachos, a paleoclimatologist at the University of California, Santa Cruz, and a co-author of the new paper, the worst-case scenario by 2300 shows "the change in mean global temperature is larger than most of the natural variability going back over the last 66 millions years related to changes in the Earth's orbit."

Harvey pointed out that "feedback processes that can speed things up or slow things down" make it difficult to "predict future change, especially over relatively short periods of time."

However, by "reconstructing the Earth's long-term climate history," this study can help scientists test the accuracy of models used to make projections about the future by comparing them to simulations of the past, which could yield useful knowledge about "how climate change could unfold in the coming decades and centuries," explained Scientifc American

"It's not an inevitable future," Harvey stressed, adding that "with immediate and stringent action to reduce climate change, the world can keep global temperatures from rising more than a few degrees above their preindustrial levels."


Our work is licensed under Creative Commons (CC BY-NC-ND 3.0). Feel free to republish and share widely.

We've had enough. The 1% own and operate the corporate media. They are doing everything they can to defend the status quo, squash dissent and protect the wealthy and the powerful. The Common Dreams media model is different. We cover the news that matters to the 99%. Our mission? To inform. To inspire. To ignite change for the common good. How? Nonprofit. Independent. Reader-supported. Free to read. Free to republish. Free to share. With no advertising. No paywalls. No selling of your data. Thousands of small donations fund our newsroom and allow us to continue publishing. Can you chip in? We can't do it without you. Thank you.

Because Climate Science 'Does Not Grade on a Curve,' Experts Says IRA Not Enough

"There is an urgent need for much more aggressive and far-reaching measures to prevent climate chaos," said the head of one progressive consumer advocacy group.

Brett Wilkins ·


'Game-Changer and Reason for Hope': House Passes Inflation Reduction Act

"We've got more to do," Rep. Pramila Jayapal said on the House floor. "But today, let's celebrate this massive investment for the people."

Jake Johnson ·


'This Is Insane': Search Warrant Indicates FBI Investigating Trump for Espionage Act Violation

"If you're not fed up," said watchdog group Public Citizen, "you're not paying enough attention."

Jessica Corbett ·


Anti-War Veterans Group Asks Biden to 'Read Our Nuclear Posture Review Before Releasing Yours'

"Are you willing to risk a civilization-ending apocalypse by playing nuclear chicken with other nuclear-armed nations? Or will you lead us toward a planet that is free of nuclear weapons?"

Jessica Corbett ·


'Big Win' for Public Lands and Climate as US Judge Reinstates Coal Lease Ban

"It's past time that this misguided action by the Trump administration is overturned," said one environmental campaigner.

Brett Wilkins ·

Common Dreams Logo