Shackleton’s Journey to the Larsen Ice Shelf
Sir Ernest Shackleton, were he to return to the Weddell Sea today, would find it unrecognizable. When his ship, the Endurance, crushed between monstrous ice floes, finally sank on November 21, 1915, he and his crew of 27 men were just east of the Larsen Ice Shelf, a trillion-ton chunk of which snapped off on July 12, 2017.
Shackleton’s “Imperial Trans-Antarctic Expedition” set out to land somewhere along Vahsel Bay and trek to the South Pole with a team of dogs. From there, they would continue north to meet a recovery ship in McMurdo Sound, thus completing the first transcontinental journey across the continent. But on January 19, 1915, their ship became stuck fast in the ice off the Luitpold Coast.
Polar ice doesn’t sit still. It drifts with variable wind and ocean currents. The floating ice carried Shackleton’s party north by northwest for 11 months before the ship slipped beneath the Southern Ocean. The entire party, with as many supplies as they could haul, along with all three lifeboats from the Endurance, set up camp on an ice floe. They were then at -68˚ 38.5' south and -52˚ 28' west, less than 200 miles from today’s Larsen Ice Shelf.
Since there are no aerial or satellite images from 1915, we can’t know the exact extent of the ice in Shackleton’s time. However, a 2008 study analyzed whaling positions, historic ice charts and contemporary observations to find “that a substantial southward shift in the ice-edge did occur.” The researchers believe that the average ice retreat from the 1930s to the 1980s amounted to a median estimate of 2.41 degrees of latitude — about 166 miles.
The Larsen shelf has been retreating rapidly for at least the past six decades. U.S. spy satellite images from 1963 of Antarctica show that the Larsen B Ice Shelf was already shrinking. The melt accelerated in ensuing decades, and in 2002, a 1,250 square mile block of ice collapsed. Within a month’s time, it broke apart into thousands of smaller icebergs. Prior to then, Larsen B had been stable for at least 12,000 years.
The calving of Larsen C has reduced the ice shelf by 12 percent, according to Project MIDAS, a U.K.-based research project. “We have been anticipating this event for months, and have been surprised how long it took for the rift to break through the final few kilometers of ice,” said Professor Adrian Luckman of Swansea University, lead investigator of the MIDAS project. The final break occurred in the middle of the Antarctic winter.
In West Antarctica, warm water is eating away the ice sheet from below. In a continent-wide study by researchers at the Lamont-Doherty Earth Observatory of Columbia University, enormous streams of surface meltwater were found flowing during the 2016 Antarctic summer. Some streams were just 375 miles from the pole and at elevations as high as 4,300 feet above sea level.
“I think most polar scientists have considered water moving across the surface of Antarctica to be extremely rare,” said lead author and glaciologist Jonathan Kingslake. “But we found a lot of it, over very large areas.”
An Australian study, published July 6, 2017 in Nature, found that ice-free areas in the Antarctic could increase 25 percent by the end of the century. “Climate change will alter the extent and configuration of ice-free areas, yet the distribution and severity of these effects remain unclear,” state the scientists.
Were Shackleton to take the Endurance into the Weddell Sea in our time, his story would be far different. In this NASA Worldview image from January 19, 2017–102 years to the day after the Endurance became irrevocably trapped in sea ice — the ocean shows as mostly open, represented by the light gray areas. Dark gray is land, and the purple highlights are sea ice.
Shackleton’s crew continued to drift northwesterly as the ice floe that was their lifeboat slowly melted and disintegrated. For five months, they let the drift of the ice bring them closer to land. But on April 9, 1916, with the floe just 50 yards wide, they took to their small boats. Facing fierce storms, gale winds and high seas, they reached Elephant Island on April 19, the first time they had set foot on land in 497 days. After a daring sea and land journey by a crew of six to reach civilization in the form of the whaling station on South Georgia island, 820 miles away, and two unsuccessful rescue attempts, on August 30, 1916, those left on Elephant Island were safely retrieved.
The extensive sea ice that once comprised the Larsen Ice Shelf as recently as Shackleton’s time will not, however, be retrieved in our lifetime.
