Arctic sea ice reaches annual minimum | ET REALITY

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Three years after its marathon journey across the ice-frozen central Arctic Ocean, the German scientific research ship Polarstern has once again reached the North Pole.

This time the expedition is shorter, two months instead of a full year, and the ship sails through the ice, not locked in or adrift. But the goal of the scientists on board is the same: to better understand how the central Arctic is changing as the planet warms.

Sea ice coverage in the Arctic reduces in spring and summer and reaches a minimum in mid-September. This year, it is on track to be the sixth lowest on record.

The record was set in 2012, and that year Polarstern was also in the Arctic.

Antje Boetius, a marine biologist, was the chief scientist for both expeditions.

Last week the ship was in the Amundsen Basin, having spent the previous week at the pole, 120 miles to the north. In an email written on board, Dr. Boetius wrote that Polarstern was returning to many of the places she visited 11 years ago. “Therefore, we can directly compare whether it is ice thickness, snow cover, ice algae, plankton composition, ocean chemistry or what lives on the seafloor,” he wrote.

The current expedition, called ArcWatch, includes more than 50 biologists, chemists and other scientists using specialized instruments brought for the trip, as well as two helicopters.

Since satellite observations of Arctic sea ice began in 1979, coverage has declined by about 13 percent per decade, a consequence of warming in a region that is warming much faster than other parts of the planet. At its peak in winter, ice covers about 6 million square miles, on average, of the Arctic Ocean. The 2012 record low was 1.3 million square miles. Most years since then they have been in the bottom 10.

This year is no exception. As of Tuesday, ice coverage was 1.63 million square miles and was just days away from reaching the year’s low, according to the National Snow and Ice Data Center in Boulder, Colorado.

Polarstern, a 400-foot double-hull icebreaker, is owned by the German government and operated by the Alfred Wegener Institute, and carries a crew of about 40, including a baker who continues the ship’s tradition of serving cake every afternoon.

During the 2020 expedition, called Mosaic, the scientific team changed every few months, but for ArcWatch researchers are on board for the entire journey, which began in northern Norway in early August and ends October 1 in port. base of the boat. , Bremerhaven, Germany. (Another difference between the two expeditions: Mosaic’s voyage was severely disrupted by the coronavirus pandemic and what turned out to be a successful effort to avoid an outbreak on board.)

During ArcWatch, researchers are also deploying buoys and instruments on the ice, part of an international collaboration to provide year-round data on climate and sea conditions in the central Arctic, one of the least accessible areas in the world, especially in winter. Using sonar equipment, the expedition is also mapping the ocean floor in remote areas of the Arctic.

“We encounter unexplored seamounts, unknown landscapes and communities of ocean life, because there is very little research infrastructure here,” Dr. Boetius wrote. “I have these great explorer moments, where we just discover.”

This is Dr. Boetius’ fiftieth deep-sea expedition. She first traveled to the Arctic three decades ago, when she was a young doctoral student. β€œIn those 30 years everything has changed, from the ice to the bottom of the sea,” she wrote. β€œI could not have imagined the climate crisis we find ourselves in today; And I talk about this with the young Ph.D. students here, who know that the Arctic they witness today will not be there for them in 30 years.”

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