Penguins spared after the giant iceberg splits into smaller pieces

Then there was the question of penguins.

Ecologists feared that the island’s huge king penguin and gentoo colonies would have to make large detours to reach their usual hunting grounds, with potentially dire consequences for the young that waited on land.

Instead, more than three years after the birth of the Antarctic Larsen C ice shelf, about 930 miles to the south, the warmer waters and the torque of the currents broke the giant into a dozen pieces, now known as A68b, A68c and so on under the US National Ice Center nomenclature system. They now appear to be heading north, where they can be a bigger problem for humans.

“As it breaks, thousands of smaller icebergs have a chance to obstruct navigation routes in the area, especially as they disperse,” said Andrew Fleming, head of remote sensing at the British Antarctic Survey, which tracked the voyage of the A68a to the north through images provided by the European Space Agency and overflights by the British Royal Air Force.

The largest section, still called the A68a, is 330 square miles, larger than New York City, with several pieces almost as large. The rupture of the A68a means that the biggest iceberg is now the A23a, which separated from Antarctica in 1986, but remained stranded on the seabed.

A British Antarctic Survey team is coming from the Malvinas Islands to assess the impact of icebergs on the area’s marine ecology and to get some information on what to expect if the Antarctic ice shelf produces more giant icebergs as global temperatures rise.

“Everyone is doing everything they can to make this happen,” said oceanographer and team leader Povl Abrahamsen, on board the RRS James Cook, who will hit icebergs in mid-February.

Navigating a pack of huge icebergs can be a risky task, however. In addition to the icebergs themselves – particularly the parts below the surface – there are waterfalls of melted ice and the prospect of more pieces breaking, causing big waves. To mitigate the risk, the mission includes two underwater robotic gliders to collect samples that will allow the team to get a better idea of ​​the type of impact such a large mass of icebergs is having on ocean conditions off South Georgia, one of the most biologically rich places on the planet and one of the largest marine protected areas in the world.

The biggest concern is how melted icebergs can disrupt the ocean’s food chain. An influx of cold freshwater can kill microscopic marine organisms called phytoplankton, starving the krill that feed on them and depleting populations of fish, seals, penguins and whales.

The area is so abundant with marine life that Norwegian whalers established a whaling station in South Georgia in the early 20th century, which has since been abandoned.

Today there are no permanent residents on the island, just a rotating team of ecologists and other scientists who track fish stocks and other wildlife, including albatrosses and seals.

The island is becoming increasingly important, however, as a basis for monitoring the number of icebergs that come off the Antarctic ice sheet and head north towards warmer waters.

Although icebergs have always broken or broken from the polar cap, the concern is that a warmer climate will flatten it out like a cone of melting snow, bringing more ice to the edge of the continent, where it will eventually come loose.

In a study published earlier this week, two geophysicists at the University of Copenhagen, Denmark, warned that climate change could cause sea levels to rise faster than initially feared, increasing the risk of flooding in densely-populated coastal regions. populated.

Aslak Grinsted and Jens Hesselbjerg Christensen searched for data dating back several centuries and found that ocean levels could rise by more than a meter if global temperatures rise by 2 degrees Celsius, more than the current projections adopted by the United Nations Intergovernmental Panel on Climate Change United, and in half a meter if temperatures rise only half a degree Celsius.

Write to James Hookway at [email protected]