---
title: "The Ice Age That Began on Baffin Island 2,000 Years Ago, and the Year It Ended"
description: "Mosses buried under the Barnes Ice Cap suggest the Laurentide started to regrow two millennia ago, until warming turned it back around 1960"
author: "Jan Sokol"
published: 2026-10-24T11:00:09Z
modified: 2026-10-25T02:02:46Z
url: https://rews.cc/a/the-ice-age-that-began-on-baffin-island-2-000-years-ago-and--c1ba73
language: en
tags: ["climate", "ice", "geology", "baffin-island", "science"]
publisher: "Rews (https://rews.cc)"
---

# The Ice Age That Began on Baffin Island 2,000 Years Ago, and the Year It Ended

*Mosses buried under the Barnes Ice Cap suggest the Laurentide started to regrow two millennia ago, until warming turned it back around 1960*

By Jan Sokol · October 24, 2026 · https://rews.cc/a/the-ice-age-that-began-on-baffin-island-2-000-years-ago-and--c1ba73

## In brief

- A Science study finds the Laurentide Ice Sheet’s last remnant, Baffin Island’s Barnes Ice Cap, began re-expanding about 2,000 years ago
- Researchers dated mosses killed by advancing ice with radiocarbon and dated the retreat with beryllium-10 measured in exposed boulders
- Nearly 200 kill dates from neighbouring ice caps are all younger than 2,000 years
- The authors say falling high-latitude sunlight outweighed a roughly 20 ppm rise in CO2 between 8,000 and 2,000 years ago
- Barnes’s mass balance turned negative by 1960. It has no accumulation zone left and is projected to vanish within a few centuries

An ice cap roughly the size of Delaware lies on the central plateau of Baffin Island, in Canada’s Nunavut. It is called Barnes, and it is all that remains of an empire. The Laurentide Ice Sheet, the largest of the Pleistocene ice sheets, once buried most of Canada under two miles of ice, reached as far south as Illinois and held around 80 meters of sea level out of the oceans. Empires rarely vanish all at once. They pull back to a province, then to a capital, then to one last palace. Barnes is the palace.

That last remnant has now revealed something about the empire’s final years. As [Jacek Krywko reported for *Ars Technica*](https://arstechnica.com/science/2026/10/ice-sheet-expansion-may-have-started-2000-years-go-but-we-canceled-that/), a team led by Nicolás Young, a geologist at Columbia University’s Lamont-Doherty Earth Observatory, reports in [a study in *Science*](https://www.science.org/doi/10.1126/science.aed3379?adobe_mc=MCMID%3D11787634674621855101061664209961508090%7CMCORGID%3D242B6472541199F70A4C98A6%40AdobeOrg%7CTS%3D1792691564) that the Laurentide stopped shrinking and began to grow again around 2,000 years ago. The researchers read this as the opening of the next glaciation. On their account it went on until about 1960, when human-caused warming reversed it.

An ice age had begun. Then it was called off.

## Frozen to the rock

Barnes can testify about its past because of the way it sits on the ground. Most glaciers are warm-based: meltwater at the bed lets them slide, and the sliding ice grinds away whatever lies underneath. Barnes is cold-based, frozen straight onto the bedrock. Young compares it to the ice you scrape off a car windshield: “It’s sort of just stuck to what it’s on.”

Ice that does not move does not destroy what it covers. As the Laurentide pulled back across the plateau, tundra plants settled the bare ground. When the ice returned it covered them where they grew and kept them there, intact, for two millennia. Among them were small mosses rooted in the soil. “And when that ice margin covers the moss, it literally kills it,” Young says.

Each of those deaths can be dated. Radiocarbon dating of the moss gives the moment the ice reached a given spot, which glaciologists call a kill date. String enough of them together and they map an advancing front, a record of conquest kept by the conquered. The team checked this against a second clock, beryllium-10, an isotope that builds up in the top few centimeters of rock left open to the sky. The boulder surfaces showed that the Laurentide had retreated inside today’s margin by 3,600 years ago and probably kept shrinking until around 3,000 years ago. The paper places the minimum after about 3,600 years ago, while [Columbia’s announcement](https://news.climate.columbia.edu/2026/10/22/climate-change-stopped-the-next-ice-age/) puts it at about 3,000.

About 70 percent of the radiocarbon dates cluster around 1800 CE, at the height of the Little Ice Age, when Northern Hemisphere glaciers reached their greatest extent in recent millennia. Young reads that famous cold spell, at Barnes, as only a late surge in an advance that was already two thousand years old.

## Witnesses still buried

The oldest evidence is still under the ice. Barnes’s margin has pulled back 200 to 800 meters since 1960, exposing mosses killed from about 1000 CE onward. Anything older is still covered. So the team looked at the neighbours, smaller ice caps on the same plateau under the same climate. Earlier studies had collected nearly 200 kill dates from beneath them, and none is older than 2,000 years. “Since the Barnes Ice Cap is right next door, it’s probably a good bet that it also started expanding 2,000 years ago,” Young says. If the margin keeps retreating, he adds, a return trip in 20 years or so might reach the 2,000-year-old plants themselves.

The final proof of the advance, in other words, may be delivered by the melting that ended it.

## Sun against carbon

The study describes two forces pulling in opposite directions. Sunlight reaching the high northern latitudes peaked some 10,000 to 11,000 years ago and has been declining ever since, pushing the planet toward glaciation. Atmospheric carbon dioxide rose by roughly 20 parts per million between 8,000 and 2,000 years ago, adding warmth. “That drop in insolation and temperatures actually overwhelmed the small temperature forcing the little bit of carbon dioxide rise over the same time span,” Young says. About 2,000 years ago the fading sun won.

This seems to clash with calculations of orbital forcing and models of carbon dioxide’s role, which had suggested the next ice age was postponed by tens of thousands of years. Young sees no contradiction. Glacial inception, he says, has usually been defined by size: ice big enough to declare an ice age. That was reasonable “because until now there’s been no way to actually pinpoint when an ice sheet first turns around and starts to expand.” His Lamont-Doherty colleague Joerg Schaefer told Columbia that “catching the start of this process with direct observations is new.”

## 1960

Then came the industrial age, and its numbers. Greenhouse gases rose by about 12 ppm between 1750 and 1850, another 50 ppm by 1960 and a further 138 ppm by 2024. “Once we hit the Industrial Revolution, we’re now pumping way more carbon dioxide at a magnitude that has never occurred in the geologic record,” Young says. By 1960 Barnes’s mass balance had turned negative, and the advance was over.

Today the ice cap has nowhere left to gain ice. In the 1960s and ’70s roughly 35 percent of its surface lay above the snow line. By the early 2000s about 3 percent did. Now none does. “An ice cap or glacier cannot survive if it does not have an accumulation zone,” Young says. His models give it a few centuries under any plausible emissions scenario, the same direction of travel seen this year in the Alps, where [Swiss glaciers lost 5.5% of their ice](https://rews.cc/a/swiss-glaciers-lose-5-5-of-their-ice-in-2026-the-second-wors-13fff3). “That will be the true very last remains of the Laurentide, disappearing for good,” he told Columbia.

## What was interrupted

Was humanity rescued, then? Young admits that no one today would want to live in an ice age climate, but a full one with great ice sheets would have taken several tens of thousands of years to arrive. Columbia puts the time needed to regain continental scale at roughly 30,000 years. “I would argue that the pumping of greenhouse gases into the atmosphere hasn’t really saved us from anything,” he says. In the 1970s some scientists warned that an ice age was coming. “It actually was happening,” Young told Columbia.

One reflection suggests itself. Those who hold power like to believe that whatever they end was cruel and deserved to end. What ended here was a rhythm older than any power on Earth.

“The pacing of ice ages over the last 2.5 million years has been one of the most consistent cycles in the Earth system that we have,” Young says. “We have evidence now that humans, and specifically greenhouse gases, have actually terminated one of the most consistent cycles on Earth.”