By: Nikki Frankel

Greenland, an island country in North America, is covered in ice that is believed to have formed during an ice age from 188,000 to 130,000 years ago. However this ice has been melting over the past years. Researchers from the University of California, Irvine and NASA’s Jet Propulsion Laboratory discovered a previously unknown manner that the ice and ocean interact while studying the Petermann Glacier in northwest Greenland. According to the glaciologists, these findings may indicate that the climate community has significantly underestimated the amount of projected sea level rise brought on by thinning polar ice.

The UCI/NASA team discovered that Petermann Glacier’s grounding line—where ice separates from the land and starts floating in the ocean—shifts significantly during tidal cycles, allowing warm seawater to intrude and melt ice at an accelerated rate. This discovery was made using satellite radar data from three European missions. The conventional understanding of grounding lines beneath ocean-reaching glaciers was that they did not migrate or experience ice melt throughout tidal cycles. According to the latest research, however, warm ocean water intrudes beneath the ice through pre-existing subglacial channels, with the grounding zone experiencing the highest rates of melt. 

The PNAS research emphasizes that during the past few decades, the Greenland ice sheet has lost billions of tons of ice to the ocean, with the majority of this loss being a result of the warming of underlying ocean waters, a result of the planet’s changing climate. According to Rignot, exposure to ocean water causes the ice at the glacier front to violently melt and erodes barriers to the flow of glaciers over the ground, speeding up the ice’s descent to the sea.