New Paper Argues That Anthropogenic Climate Change Reversed Impending Ice Age

      The idea that we could reverse an impending Ice Age has been around for a while. Climate scientist James Hansen once proposed the idea as plausible. He even suggested we could manufacture chlorofluorocarbons (CFCs) with very high global warming potential to create an atmosphere on Mars that could hold in heat via the greenhouse effect. A new paper published in Science argues that we may already have prevented an impending Ice Age.

     Scientists say we are currently living through an ice age that began 34 million years ago, with its last glacial period, marked by colder temperatures and glacial advance, ending about 11,700 years ago. Since then, we have been in an interglacial period known as the Holocene, but a resumed glacial period would be expected at any time. The study focuses on the retreat of Canada's Barnes Ice Cap, which was initiated around 95,000 years ago, reached its maximum about 20,000 years ago, reached its smallest size 3,600 years ago, and began growing again 1,600 years later, or 2000 years ago. That it began to grow again, the researchers say, is a sign of glaciation. However, the glacier is now nearing its final days as anthropogenic warming reversed its growing trend.

      According to an article about the study in Smithsonian Magazine:

“The Laurentide Ice Sheet dominated the landscape of modern-day Canada and the northern United States tens of thousands of years ago. At its peak around 20,000 years ago, it covered almost 30 percent of the continent, extending from above the Arctic Circle to what is now Illinois. The ice was more than two miles thick in some spots.”

“All that’s left of this formidable feature today is the Barnes Ice Cap. It’s a Delaware-size ice cap on central Baffin Island in Nunavut, Canada.”

     Over the past 2.6 million years, large continental ice sheets have proliferated, and our Earth system has been cycling between glacial and interglacial periods. The researchers utilized a form of beryllium in newly exposed bedrock and surrounding boulders as a proxy for exposure to the atmosphere and to cosmic rays, which means the ice had melted when exposure occurred. They also carbon-dated the recently exposed dead vegetation to figure out when it first died, corresponding to when the ice cap last expanded across that area.

     Study co-author Joerg Schaefer, a geochemist at Columbia University, noted:

“Our approach helped us see the first steps of ice-sheet growth preserved in the landscape. It gave us a rare opportunity to understand how re-glaciation begins and how the Laurentide Ice Sheet re-forms.”

     What implicates anthropogenic climate change is when the ice cap began shrinking again. It was dated to 1960, when greenhouse gas emissions from industrialization began to grow much faster in the atmosphere.

     According to Lamont-Doherty Earth Observatory, where the researchers work:

“The Barnes Ice Cap is frozen directly to its underlying bedrock. Unlike most glaciers, it does not slide, and thus preserves the vegetation that grew at earlier times when the glacier was small and was subsequently entombed by its expansion. Vegetation exposed since the glacier started retreating in 1960 can be sampled, allowing scientists to determine its age by analyzing traces of carbon-14, a harmlessly radioactive form of atmospheric carbon that collects in organisms while they live and breaks down at predictable rates after they die.”

“If you do this enough times, you can actually develop a timeline of that ice margin systematically advancing over plants. You’re actually tracking the expansion of that ice margin,” says Young.

“By combining analyses of vegetation preserved beneath the Barnes Ice Cap and smaller recently melted ice caps in the region, the researchers pieced together a climate history. The Laurentide reached its minimum dimensions about 3,000 years ago, then started re-expanding about 2,000 years ago when the climate became cold enough for ice to accumulate.”

     It is debatable when re-glaciation begins, and it can take thousands of years from that initial beginning to when large, mile-or-more-thick glaciers advance over continents. The findings validate the scientists who thought in the 1970s that a new ice age was beginning, based partly on cooler global temperatures from about 1940 to about 1970.

“By the 1960s, Earth’s climate had warmed enough that the Barnes Ice Cap lost more ice in the summer than it added in winter. The next glaciation fizzled out. According to models of the glacier’s future, it will melt completely within the next few centuries. “That will be the true very last remains of the Laurentide, disappearing for good,” Young says.

     According to Shaun Marcott, an Earth scientist at the University of Wisconsin-Madison who did not participate in the study:

“Humans are now geologic agents capable of thwarting millions of years of natural glacial cycles and offsetting Earth’s climate for hundreds of thousands of years to come.”

     The evidence appears to be pretty good that re-glaciation was initiated 2000 years ago and that shrinking of the ice sheet began around 1960. Should we adopt a different view about anthropogenic climate change if this is true? Did it protect us from the horrors of an Ice Age? If this is true, it suggests that anthropogenic climate change is indeed a powerful lever for changing the Earth system but also that it ended up being beneficial in terms of preventing an impending Ice Age. 

 

 

References:

 

Two thousand years ago, a new ice age began—but human-caused climate change recently reversed it, according to new research. Margherita Bassi, Smithsonian Magazine. October 27, 2026. Two thousand years ago, a new ice age began—but human-caused climate change recently reversed it, according to new research

An ice age was coming. Our emissions reversed it. Arden Dier with Newser.AI. Newser. October 28, 2026. An ice age was coming. Our emissions reversed it

Late Holocene reexpansion of the Laurentide Ice Sheet. Nicolás E. Young, Gifford H. Miller, Martha Raynolds, Helga Bueltmann, Scott J. Lehman, Jonathan H. Raberg, Kylie Seward, Simon L. Pendleton, John T. Andrews, Patrick J. Webber, and Joerg M. Schaefer. Science. 22 Oct 2026. Vol 394, Issue 6822. pp. 455-459. Late Holocene reexpansion of the Laurentide Ice Sheet | Science

Climate Change Stopped the Next Ice Age. Lamont-Doherty Earth Observatory. Columbia Climate School. October 22, 2026. Climate Change Stopped the Next Ice Age | Lamont-Doherty Earth Observatory