Antarctica is desolate, deadly cold, windy and is surprisingly dry. It holds 90% of the worlds ice in an area somewhat larger then the continental United States. If as expected, we continue to burn fossil fuels, we are putting our coastlines and the entire biosphere in grave danger. If we burn all the fossil fuels currently in the ground it would melt all of the ice in Antarctica and raise sea levels to a eye popping 150 feet. The massive ice streams on the continent have flowed into the ocean for thousands of years. The point where the glacier leaves the land mass is called the grounding line, and the glacier extending into the ocean is called an ice shelf. These ice shelves buttress the glacier keeping the flow in check so that the land ice does not empty rapidly into the ocean.
NASA’s Operation IceBridge has been exploring the massive Getz Ice Shelf in West Antarctica for several years. The shelf is over 300 miles long and anywhere from 20 to 60 miles wide and it is experiencing one of the highest basal melt rates in all of Antarctica. IceBridge is building a record of how ice is responding to changes in the polar environment. Researching ice is very complicated because it has multiple factors such as the temperature throughout the ice, ocean water temperature, currents, upwelling, air temperature, and shelf pinning points.
This IceBridge data record is now in it’s eighth year and it is providing clues on how the ice is responding to the changing polar environment. The scientists have returned with jaw dropping images of Antarctica, some of which I added to this story.
Nathan Kurtz, IceBridge project scientist and a sea ice researcher at NASA’s Goddard Space Flight Center is the leading scientist and he believes that Getz and others in Antarctica are experiencing some of the highest basal melt rates in the world.
Kurtz notes that the team has flown over the Getz Ice Shelf many times before. Flight paths are often exact repeats of those flown in previous years, which helps scientists understand how the height of the ice surface changes over time. This year, new flights over Getz were added to the existing observations. Scientists mapped the bathymetry (shape and depth of the seafloor) below the ice shelf, and they mapped the ice surface and bedrock upstream of the grounding line.
The flight over Getz is just one of a number of key areas flown during the IceBridge campaign. Each flight plan is prioritized in order of importance: baseline (the highest priority), high, medium, and low. The flight on November 5 over Getz, for example, was categorized as “high” priority. Since the start of 2016 science flights on October 14, the team has flown six out of eight baseline missions, eight out of 15 high priority lines, and one medium and low priority mission each. Research flights for the season continue through November 18.
“We are in pretty good shape so far, having flown so many missions due to a combination of favorable weather, no major airplane issues, and all instruments operating well,” Kurtz said. “We’re about four weeks into the campaign, and it’s possible we could tie the record of most flights flown with Operation IceBridge if things continue to go well.”
Climate Reality reports on basal melt and the work of Ala Khazendar, a geophysicist and polar expert at NASA's Jet Propulsion Laboratory in Pasadena, Calif..
"You have this floating plate of ice being fed by the glaciers flowing from the interior of the continent," he says, "while having ocean water underneath it." He calls the shelves "the gates of Antarctica.”
Although the shelves float, they're still connected to the mainland. The point at which the ice shelf is no longer supported by bedrock is called the "grounding line."
A team from JPL has been studying that grounding line in several places along the edge of the West Antarctic ice sheet. They used radar to look beneath the ice. In particular, overflights have targeted ice shelves along the West Antarctic ice sheet known as the Amundsen Sea Embayment.
They've found that the ice is melting faster than they've ever seen. The researchers believe the cause is warm water circulating beneath the ice shelf. The melting was most pronounced from 2002 to 2009. (The influx of warmer water to the region stalled recently, and the rate of melting seems to have slowed somewhat.)
NASA’S Climate Change: Vital Signs of the Planet reports on the winding down of the annual study of changing Antarctic ice, and the news that Antarctica’s sea ice is at the lowest satellite level since 1979.
“Operation IceBridge is particularly well suited to measure changes in polar ice: it carries probably the most innovative and precise package of instruments ever flown over Antarctica,” Newman said.
"This campaign was possibly the best Antarctic campaign IceBridge has ever had,” said John Sonntag, IceBridge mission scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. "We flew as many flights as we did in our best prior campaigns down here, and we certainly got more science return out of each flight than we have before, due to steadily improving instrumentation and also to some exceptionally good weather in the Weddell Sea that favored our sea ice flights."
Antarctica is heading into austral summer, a period of rapid sea ice melt in the Southern Ocean. But this year the sea ice loss has been particularly swift and the Antarctic sea ice extent is currently at the lowest level for this time of year ever recorded in the satellite record, which began in 1979.
"We flew over the Bellingshausen Sea many times during this campaign and saw that areas that are typically covered by sea ice were just open water this year,” said Nathan Kurtz, IceBridge’s project scientist and a sea ice researcher at NASA Goddard. "It is a reminder that it is important that we continue the time series of IceBridge measurements in the area so that we can measure both changes in sea ice extent and in sea ice thickness to assess the future trajectory of the ice pack and its impact on the climate.”
Near the grounding line—the boundary where the ice sheet loses contact with bedrock and begins to float on the ocean. Here, a web of deep cracks, or crevasses, spans the icescape. Large tabular icebergs separate from the Getz Ice Shelf with sea ice forming in their stead (NASA/Brooke Medley). Northern edge of the Getz Ice Shelf that is fed by the Devicq Glacier. Brash ice ( a patch of accumulated small fragments of floating ice) can be seen forming near the edge of the shelf, and is being exported out to sea (NASA/Brooke Medley) Evidence of a break along the front edge of Getz Ice Shelf, Antartica x YouTube Video