Arctic ice cap was regrowing toward a new ice age until 1960s warming, study finds

Overview

Updated Yesterday

The last remnant of the ice sheet that once covered most of North America began growing again about 2,000 years ago — the early stage of a new glacial period. A study in Science shows the Barnes Ice Cap on Baffin Island expanded until around 1960, when rising summer temperatures reversed the growth.

The finding answers a long-standing question about when Earth's next ice age would have begun. It also frames modern warming in stark terms: a naturally cooling planet was heading toward glacial inception just as industrial emissions cut the cooling short.

Why it matters

The finding suggests Earth's next glacial period was already beginning — and that 20th-century warming cut it off.

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Key Indicators

~2,000

Years the ice sheet expanded before reversing

The Laurentide remnant regrew from about 2,000 years ago until roughly 1960.

1960

Year the regrown ice cap peaked

Aerial photos show the Barnes Ice Cap at its largest since regrowth around 1960, then retreating.

Ice surface above the snowline by the early 2000s

Down from 35% in 1960–1980; the accumulation area vanished after 2010.

~500 m

Median ice margin retreat since 1960

The study measured the Barnes Ice Cap margin retreating 200–800 meters between 1960 and 2022.

Voices

Curated perspectives — historical figures and your fellow readers.

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People Involved

Nicolas Young

Lead author; geologist at Lamont-Doherty Earth Observatory

Published the Science study with colleagues

Organizations Involved

Lamont-Doherty Earth Observatory

Earth science research institute

Host institution of the study's lead author

Earth sciences research institute at Columbia University.

Science Corporation

Peer-reviewed scientific journal

Published the study

Weekly peer-reviewed journal published by the American Association for the Advancement of Science (AAAS).

Timeline

1960 c. 3600

5 events Latest: Yesterday

Tap a bar to jump to that date

c. 3600
Laurentide Ice Sheet reaches minimum size
Upcoming Climate

The ice sheet that once blanketed most of North America shrank to its smallest interglacial extent, retreating within the modern Barnes Ice Cap margin.
c. 3600 BP
c. 2000
Ice sheet begins regrowing
Upcoming Climate

Summer insolation decline lowered the snowline; the ice sheet's mass balance turned positive and it began expanding — the natural onset of the next glaciation.
c. 2000 BP
October 2026
Science paper: regrowth reversed by modern warming
Latest Research

Young and colleagues show the Laurentide remnant expanded for ~2,000 years until ~1960, then retreated; they attribute the reversal to anthropogenic greenhouse warming.
Yesterday
2023
Moss kill dates map Common Era ice expansion
Research

A companion study dated vegetation entombed by expanding Baffin Island ice caps, finding the 1780–1880 cold peak approached ice-age inception conditions.
2023
1960
Regrown ice cap reaches peak size
Climate

Aerial photographs show the Barnes Ice Cap near its historical maximum around 1960, after which summer warming began driving retreat.
1960

Scenarios

Independent dating confirms the ~2,000-year regrowth onset

Possible Resolves by Q2 2029

Discussed by: Glaciology and paleoclimate researchers

The study's core claim is that the Laurentide remnant's reexpansion began about 2,000 years ago, marking glacial inception. Other teams are already dating vegetation and rock emerging under retreating Arctic ice caps. A confirming study using independent radiocarbon or beryllium-10 samples would solidify the timeline.

Barnes Ice Cap enters irreversible terminal retreat

Likely Resolves by Jan 1, 2031

Discussed by: Glacier monitoring agencies and the study authors

The ice cap's accumulation area has been effectively zero since 2010, meaning it loses ice every year. The study authors project complete melt within the next few centuries. Continued negative mass balance in annual monitoring would confirm the ice cap is past the point of recovery.

Scientists challenge the 'next glaciation interrupted' framing

Unlikely Resolves by End of 2028

Discussed by: Paleoclimatologists

Some researchers may argue the 2,000-year expansion was regional fluctuation on Baffin Island rather than true glacial inception, which requires continental-scale ice growth. A peer-reviewed critique would test whether the study's framing overstates the evidence.

Historical Context

3 moments from history that rhyme with this story — and how they unfolded.

c. 1300–1900

Little Ice Age (c. 1300–1900)

A centuries-long cooling of the Northern Hemisphere, strongest in the Arctic, that expanded glaciers worldwide. On Baffin Island, ice caps covered more than 11,000 square kilometers at the 1780–1880 peak — over a hundred times the area glaciated today.

Then

Glaciers advanced and cold summers persisted for centuries across the North Atlantic region.

Now

Cooling after about 1880 reversed as industrial greenhouse gas emissions rose, ending the Little Ice Age.

Why this matters now

The Little Ice Age is the recent peak of the same late-Holocene cooling trend the study says was driving the Laurentide remnant's reexpansion into a new glacial period.

1970s

1970s 'impending ice age' speculation

A handful of scientists and media reports in the 1970s suggested Earth might be heading toward a new ice age, based on a long cooling trend since the 1940s. The idea drew sharp skepticism and faded as warming became clear.

Then

The ice-age speculation was largely dismissed when global temperatures began rising sharply in the 1980s.

Now

The episode became a cautionary tale about overinterpreting short-term trends.

Why this matters now

This study provides direct physical evidence that a glacial inception trend was genuinely underway around 2,000 years ago — and was cut off by anthropogenic warming — lending new context to that old debate.

c. 115,000 years ago

Eemian interglacial to last glaciation (c. 115,000 years ago)

The last interglacial period ended when declining Northern Hemisphere summer insolation allowed Northern Hemisphere ice sheets to regrow, eventually building the ice masses of the last ice age. That inception is the canonical example of how interglacials give way to glaciations.

Then

Summer cooling and snowline descent triggered ice sheet expansion across Arctic North America and Eurasia.

Now

Ice sheets grew for tens of millennia, reaching the Last Glacial Maximum about 20,000 years ago.

Why this matters now

The same insolation-driven mechanism the Eemian example illustrates is what the study says was beginning again — until greenhouse forcing interrupted it.