Why are two glaciers in Greenland that are sitting side by side melting at drastically different rates? Thanks to NASA’s OMG campaign, scientists now know why.

Tracy And Heilprin

It was in 1892 that explorers discovered the Tracy and Heilprin glaciers in northwest Greenland. The two glaciers sit beside each other, and scientists and researchers have been observing and measuring them sporadically since discovery.

Interestingly, even if Tracy and Heilprin experience the same weather and ocean conditions and flow into the same gulf, researchers observed the two glaciers are melting at drastically different rates. In fact, in the last 125 years, Heilprin has only retreated less than 4 kilometers (2.5 miles) upstream, whereas Tracy has already retreated over 15 kilometers (9.5 miles) upstream. That means that Tracy has been losing ice four times faster than its neighbor.

About 10 years ago, NASA’s Operation IceBridge found a significant difference between the two glaciers that helped them understand the ice melt discrepancy. Using ice-penetrating radars, researchers found that Tracy actually sits on a much deeper bedrock than Heilprin.

Scientists believed that this difference likely affects the melt rates of the two glaciers, especially since the top ocean layer around Greenland is much colder than the deeper waters. Since Tracy sits on a deeper bedrock, it is more exposed to the warm water.

NASA OMG Campaign

Now, a new study published in the journal Oceanography presents additional data that further explains the ice melt difference between the two glaciers and highlights the role of oceans when it comes to ice loss.

NASA’s Oceans Melting Greenland (OMG) campaign, which was designed to survey the ice and ocean conditions all around the coastline of Greenland, sent a boat into the Inglefield Gulf to collect more data on Tracy and Heilprin and discovered that there is a flow of water that’s draining from under Tracy.

Evidently, what happens is when the buoyant freshwater escapes from under Tracy, it also brings with it the warmer subsurface water, which then goes back up and swirls onto Tracy’s ice face.

“Most of the melting happens as the water rises up Tracy's face. It eats away at a huge chunk of the glacier,” said Josh Willis, principal investigator of OMG.

Together, Tracy’s depth and the river flow beneath it are responsible for why, despite sitting side by side, Tracy and Heilprin have completely different rates of ice melt.