Ancient Greenland rocks reveal how quickly seas could rise again

Ancient Greenland rocks reveal how quickly seas could rise again

• Prudhoe Dome in Greenland melted completely within the past 10,000 years
• Melting occurred under temperatures only slightly warmer than today
• Study warns of dramatic sea-level rise if similar melting occurs now.

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When scientists drilled through more than 1,600 feet of ice at Prudhoe Dome in northwest Greenland, they expected to confirm that this remote section of the ice sheet had remained frozen since the last ice age. Instead, the rocks they recovered told a far more alarming story.

Chemical signatures preserved in the sediments show that Prudhoe Dome completely melted sometime in the past 10,000 years. The finding, published this week in Nature Geoscience, means a large part of Greenland vanished under temperatures not much warmer than those of today, the Washington Post reported.

Why Prudhoe Dome matters

Prudhoe Dome sits near the edge of the Greenland ice sheet, a frozen mass more than 50 miles wide and towering above the Arctic landscape. Until now, scientists believed this region was relatively stable, even during warmer periods in Earth’s recent history.

The new evidence suggests otherwise. If melting on a similar scale occurred today, global sea levels could rise between about 7.5 inches and 2.4 feet, enough to dramatically worsen flooding in coastal cities worldwide.

Reading the past with light and electrons

To determine when the ice disappeared, researchers used a technique called luminescence dating. When sediments are buried beneath ice, their crystal structures trap electrons created by natural radioactivity. Once exposed to sunlight, those electrons are released.

By measuring how many electrons were stored, scientists calculated that the sediments beneath Prudhoe Dome had been buried for only about 7,100 years. That places the melting during a period when Arctic temperatures were roughly 3 to 5 degrees warmer than in the 19th century, comparable to conditions reached today.

What it says about climate sensitivity

The findings add to mounting evidence that Greenland’s ice sheet is highly sensitive to even modest warming. The Arctic is heating up faster than any other region on Earth, a phenomenon known as Arctic amplification. As sea ice retreats, darker ocean waters absorb more sunlight, accelerating warming and ice loss.

Scientists say this feedback loop could push Greenland closer to a tipping point, beyond which large-scale melting becomes irreversible.

Lessons for future sea-level rise

Modern climate change is driven by greenhouse gas pollution rather than natural shifts in Earth’s orbit, which caused ancient warming episodes. Still, researchers say the past offers a crucial benchmark for improving models that forecast how ice responds to rising temperatures.

Greenland already contributes more to global sea-level rise than any other ice mass. If the entire ice sheet were to melt, oceans would rise by roughly 24 feet.

A warning written in stone

The rocks beneath Prudhoe Dome act like a geological memory, recording how Greenland behaved under conditions similar to those unfolding now. Scientists say the message is clear: the ice sheet has disappeared before, and it did not require extreme heat to do so.

Understanding that vulnerability, researchers argue, is essential for preparing coastal communities for what may lie ahead as the planet continues to warm.