“It was just getting started, everything was normal, the next glaciation was about to happen—and yet it stopped,” Nicolás Young told SciTechDaily.
New research indicates that anthropogenic warming has effectively interrupted a natural cooling cycle that was beginning to trigger Earth’s next ice age. Scientists discovered that an ice cap in northern Canada began expanding roughly 2,000 years ago, a development that signaled the onset of a new glacial period, SciTechDaily reported.
The Barnes Ice Cap expansion
The study, published in the journal Science, focuses on the Barnes Ice Cap on Baffin Island in Nunavut, Canada. This ice mass is a surviving remnant of the massive Laurentide Ice Sheet, which once covered much of Canada and the northern United States, extending as far south as Illinois with thicknesses exceeding two miles.
Researchers identified that the Barnes Ice Cap reached its smallest extent approximately 3,000 years ago. According to SciTechDaily, conditions became cold enough for ice to accumulate again about 1,000 years later, marking the start of a renewed growth phase.
Unlike typical glaciers that slide across the terrain and erase geological history, the Barnes Ice Cap is frozen to its bedrock. This stability allowed it to bury vegetation rather than scraping it away. By using carbon-14 dating on these preserved plants, the team reconstructed a precise timeline of the ice margin’s advance.
Carbon emissions reverse natural ice expansion
The natural progression toward a new ice age hit a hard ceiling in the 1960s. As global carbon emissions accelerated, warmer summers began to reverse the ice expansion. Wired reported that the ice cap has been losing more ice during summer months than it gains during the winter.
The rate of decline is measurable and accelerating. Since the 1980s, the margins of the ice cap have retreated at an average rate of 4 meters per year, according to Wired.
This retreat has effectively undone two millennia of natural ice accumulation. Andrew Wickert, an associate professor of environmental science at the University of Minnesota Twin Cities, noted that even as emissions were just beginning to ramp up, they had already caused the major North American ice sheet to start retreating.
| Time Period | Ice Cap Status | Primary Driver |
|---|---|---|
| ~3,000 Years Ago | Minimum extent reached | Natural climatic fluctuation |
| ~2,000 Years Ago | Expansion began | Natural cooling/Glacial onset |
| 1960s | Expansion reversed | Rising summer temperatures |
| 1980s–Present | Rapid retreat | Increased carbon emissions |
Disrupting predictable geological cycles
The discovery provides retroactive validation for 1970s climate theories. While some critics previously mocked scientists who warned of an imminent ice age, Nicolás Young noted that the evidence now suggests those scientists were correct about a pending glaciation.
However, the mechanism of this glaciation was fundamentally altered. Ice ages are typically triggered by the shifting positions of continents, which influence ocean and atmospheric circulation patterns, according to the Utah Geological Survey.
By injecting greenhouse gases into the atmosphere, humans have “jolted the system,” Young stated. This disruption removes the “foundation” required for future ice sheets. The Laurentide once provided a ready starting point for expansion; without this surviving mass, any future glaciation would have to develop from scratch without that existing frigid foothold.
The Week reported that while the process of an ice age is slow—taking thousands of years to transform the climate—the current warming has disrupted a cycle that was once considered extremely natural and predictable.
The future of the Laurentide remnant
Current climate models suggest the Barnes Ice Cap is on a trajectory toward total disappearance. Researchers project the ice mass will melt completely within the next few centuries.
The loss of this remnant would mark the final disappearance of the Laurentide legacy. Scientists can no longer say when, or if, another glaciation might begin given the current elevation of greenhouse gas concentrations.
“What has been an extremely natural and predictable phenomenon is now gone,” Young said.
