Greenland

A large glacier in northwest Greenland is interacting with ocean tides, scientists say, resulting in previously unknown melting and potentially faster rise in sea levels.

The group of glaciologists from the University of California Irvine (UCI) and NASA’s Jet Propulsion Laboratory (JPL) published the study in the journal Proceedings of the National Academy of Sciences.

Observations of the Petermann Glacier have revealed that the glacier’s ground line – the area where the ice sheet begins to extend into the ocean – can change significantly as the tides rise and fall each day.

Petermann’s grounding line “moves between 2 to 6 kilometers as the tides rise and fall,” according to Enrico Ciracì, the study’s lead author and UCI scientist.

This is an important finding: the traditional view among scientists was that the ground line doesn’t move with the tides – and this introduces another major source of melt that may be accelerating sea level rise.

Between 2016 and 2022, warmer tidal cycles melted an eight-foot-high hole in the bottom of the glacier along the fill line – big enough that two Statue of Liberty could be stacked on top of each other in the your inside.

The phenomenon could get worse in the coming years and decades, as the temperature of the oceans rises. CNN recently reported that sea surface temperatures reached the highest levels on record this spring – a spike that has alarmed scientists, who fear it could be part of a worrying new trend.

The study raises further concerns about the already alarming prospect of rising sea levels, which threatens coastal areas around the world. According to NASA, melting Greenland ice is the biggest contributor to sea level rise, which has been accelerating in recent years. But current projections do not account for this newfound interaction between ice and tidal warming.

“These ice-ocean interactions make glaciers more sensitive to ocean warming,” argued co-author Eric Rignot, UCI professor and NASA JPL researcher. “These dynamics are not included in the models and, if we included them, they would increase sea level rise projections by up to 200% – not just for Petermann, but for all glaciers that end in the ocean, i.e. most of of northern Greenland and all of Antarctica”.