Konrad Steffen/CIRES, University of Colorado

Heavily crevassed area of Jakobshavn Isbrae near the glacier front.

When cracks appeared this month on one of Greenland’s largest glaciers, the Jakobshavn Isbrae, scientists in Minnesota and Ohio were watching with the help of new tools that come at a crucial time for monitoring such changes around the globe.

It looks like a rift could be opening deep into the glacier, Ian Howat of Ohio State University wrote in a quick email to Paul Morin at the University of Minnesota.

Morin agreed. The satellite image they had just received was something of a red flag, signaling that a large break in the far-away glacier might be imminent. So Morin alerted NASA, a sponsor of their research.

“We sent emails back and forth,” Howat said. “While that was taking place...the next satellite image came in — and, boom, here we go — it actually had happened!”

An ice chunk roughly one-eighth the size of Manhattan Island in New York had cracked away from the glacier.

It was the first time scientists had been able to see a break of that magnitude coming and then watch it happen in something very close to real time.

This stepped-up glacier watching is part of a new program at the U of M’s Antarctic Geospatial Information Center, where Morin is the director, and at Byrd Polar Research Center at Ohio State.

It comes at a time when scientists have urgent reasons to closely monitor glaciers and polar regions. Among other reasons, they are watching for events that could lead to rising oceans and other effects related to global warming.

Retreating glacier, rising seas
In this case, they were monitoring one of the largest and liveliest glaciers on Greenland’s vast ice sheet. The Jakobshavn Isbrae has retreated more than 27 miles over the past 160 years, but the pace appears to be stepping up: six of those miles came in just the past decade, NASA said in a report about the research.

Scientists estimate that as much as 10 percent of all ice lost from Greenland is coming through Jakobshavn, which is also believed to be the single largest contributor to sea level rise in the northern hemisphere.

Currently, sea level is increasing at about 1.25 inches per decade, and researchers estimate Greenland is contributing about 15 percent of this rate, according to Climate Central,  the non-profit repository for climate change information.

This wouldn’t happen for centuries if at all, but it gives you an idea how much ice is in Greenland: if all of it returned to the ocean, sea level would rise about 23 feet, Climate Central says.

No wonder scientists wanted better methods for monitoring icy Greenland.

When this latest massive chunk of the Jakobshavn glacier fell away on July 6 and 7, it set back the calving front — where the ice sheet meets the ocean — nearly a mile in one day. Now the front is further inland than at any time previously observed, NASA said.

Courtesy of NASA via DigitalGlobe

"While there have been ice breakouts of this magnitude from Jakobshavn and other glaciers in the past, this event is unusual because it occurs on the heels of a warm winter that saw no sea ice form in the surrounding bay," Thomas Wagner, cryospheric program scientist at NASA said in the report.

"While the exact relationship between these events is being determined, it lends credence to the theory that warming of the oceans is responsible for the ice loss observed throughout Greenland and Antarctica," he said.

From satellite to email
Scientists have monitored glaciers for a very long time. What’s new is the capability of doing it with this level of precision and timeliness.

The research team had identified regions of interest for scientific studies and provided those targets to satellite companies, Howat said in an interview with MinnPost.

“Whenever a satellite goes over one of those regions and makes an image we get an email alert,” he said.

The alerts signaling fresh images come almost daily — not only of the Jakobshavn Isbrae but also of the massive Kangerlugssuaq, and Helheim glaciers. And the research team gets weekly updates on smaller glaciers.

The images come from several satellites, including Landsat, Terra, and Aqua, NASA said. In the days leading up to the breakup, the team also received images from DigitalGlobe, the commercial vendor which provides images for GoogleEarth.

The whole system just geared up this summer, Howat said.

Next: targets on glaciers
Now, Morin from the U of M is in Greenland setting up targets on glaciers that will be visible from space.

“They are basically crosses you put out on the ice or the rock,” Howat said. “You can see them in the high resolution imagery... After he puts them out, he gets a precise position for them using a GPS receiver.”

Such ground control points can be used to better interpret the images and to make more accurate maps.

NASA and the National Science Foundation also have provided funding for GPS sensors, cameras, and other scientific equipment to be planted on top of the ice sheet to monitor changes and understand the fundamental workings of the ice.