Greenland’s seemingly immovable, ice-covered landscape is revealing an ancient secret beneath its frozen core—one that could drastically reshape how we understand future sea-level rise. During the Pleistocene epoch, which began around 2.7 million years ago, Greenland’s ice sheet expanded and contracted with global climate shifts. But new evidence suggests these shifts were far more dramatic than previously believed.

A Surprising Find from the Depths of the Ice

In 1993, a two-mile-deep ice core was extracted from the Greenland Ice Sheet Summit and stored in a Colorado freezer. The real surprise came decades later, at the very bottom of the core: three inches of perfectly preserved sediment containing ancient tundra life.

This discovery—poppy seeds, willow twigs, moss spores, and insect parts—was found beneath 1.9 miles (3 km) of solid ice, suggesting that central Greenland was once an ice-free tundra under a cold, dry sky.

“These fossils are beautiful,” said Paul Bierman, University of Vermont scientist and co-lead of the study. “But, yes, we go from bad to worse,” he added, referencing the stark implications for climate change.

READ MORE: Viking and Fincantieri to Launch World’s First Hydrogen-Powered Cruise Ship by 2026

Unlocking the Past to Predict the Future

High-energy isotope ratios and argon dating suggest Greenland’s summit was last exposed to open air within the past 1.1 million years, and that the region has remained under continuous ice cover for at least 250,000 years.

Supporting evidence from a separate core near the coast revealed plant remains dating back just 416,000 years—underscoring that Greenland’s ice sheet has disappeared and reappeared multiple times in Earth's recent history.

Fossils Reveal a Warmer, Ice-Free Greenland

Under a microscope, what first appeared to be specks turned out to be detailed remnants of an ancient ecosystem: arctic poppies, spike-moss, fungal bodies, and insect parts. These findings confirm that central Greenland was once home to a tundra landscape—and not just during minor warm spells.

“And then we found Arctic poppy—just one seed of it,” said graduate researcher Halley Mastro. “That’s a tiny flower really good at adapting to the cold. It tells us Greenland’s ice melted and there was soil, because poppies don’t grow on top of miles of ice.”

Sea-Level Implications: Coastal Cities at Risk

Bierman warns that a nearly complete melt of Greenland’s ice sheet in the coming centuries or millennia could raise sea levels by up to 23 feet.

“Look at Boston, New York, Miami, Mumbai, or any other coastal city around the world, and add 20-plus feet of sea level. It goes underwater,” he said. “Don’t buy a beach house.”

With sea levels currently rising by over an inch each decade—and accelerating—the consequences of inaction are stark. Projections indicate several feet of rise by the end of this century.

A Fragile Fortress Under Threat

Penn State climate scientist Richard Alley, who reviewed the new research, said:

“This confirms earlier evidence that significant sea-level rise occurred even when climate drivers weren’t extreme. It’s a warning of what we might cause if warming continues.”

The study’s findings offer direct, unambiguous evidence: polar ice sheets can retreat far and fast—and coastal cities of the future may soon be forced to reckon with this ancient and recurring truth.

Keep abreast of the top ESG Events on OneStop ESG Events.

OneStop ESG Educate: Your go-to source for top ESG courses and training programs tailored to your needs.