Up Close With a Calving Antarctic Iceberg

By Eric Betz | November 15, 2016 1:07 pm

NASA Goddard sea ice scientist Jeremy Harbeck shot this image of an iceberg calving from the Getz Ice Shelf during a recent Operation IceBridge flight. (Credit: Jeremy Harbeck/NASA)

Last year, an iceberg the size of Manhattan calved off the vast Getz Ice Shelf in West Antarctica and pushed off into the ocean. The shoreline cliffs of this frosty new island, dubbed Iceberg B-34, would rise hundreds of feet above the surface, and stretch some 1,000 feet below the Amundsen Sea. And yet, this sensational event pales in comparison to the persistent melt here.

An ice shelf forms where inland glaciers meet the ocean. Here, sheets of ice slowly slide off land, where they permanently float atop the sea. At land’s edge, these shelves can be more than half a mile thick. These features are critical brakes on melting land ice because they slow its journey to the sea. And Getz is enormous. The flat expanse of this ice shelf stretches hundreds of miles long and dozens of miles wide. But as warm ocean water washes up beneath the ice shelf’s base, it’s rapidly melting it from below, which causes more icebergs to calve off the edges.

For the past several weeks, NASA’s been flying its DC-8 airborne laboratory over Antarctica. I embedded with them to get a closer look at the ice and their operation. And flying over the Amundsen Sea Embayment last week, it was easy to spot calving icebergs where the land ice meets the ocean.

But farther inland, there are fewer obvious signs of rapid change. Even from 1,500 feet over the ice, Getz appears to extend forever with little change in its flat topography. But here and there, crisscrossing sections of crevasses appear, looking like the tops of freshly baked peanut butter cookies. Zoom out though, and space imagery shows large channels forming over recent decades. Scientists have watched some of those channels grow by more than 12 miles.

The IceBridge missions provide critical ground truths for studies of glaciers and sea ice. The team flies Getz every year, and without that data, scientists wouldn’t be able to deduce the thickness of the ice or get a detailed picture of how Antarctic ice is changing.


Discover associate editor Eric Betz joined the Operation IceBridge team at their base in Punta Arenas, Chile.

CATEGORIZED UNDER: Environment, top posts
  • joseph2237

    At this rate I doubt it will take fifty years to melt the entire Antarctic ice cap. Actually the failure of Antarctic to cool the planet will appear before all the ice disappears.since the melting has begun the break point should not be too far away. It also means that reducing the carbon emissions may not be effective and the deniers win. Better learn how to swim.

    • Peter Anderson

      It will be even faster. With an average temperature of -59 F, all we need is another 100 degrees or so of warming and that ice cap is toast.

      • joseph2237

        I think you don’t need that much heat. We maybe looking at an exponential factor of speed and heat.



Briefing you on the must-know news and trending topics in science and technology today.

See More


Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!

Collapse bottom bar