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Unprecedented Change in Antarctica's Sea-Ice Puzzles Scientists, Say They 'Can't Predict Its Future Anymore'

Climatic records of Antarctica from the 20th century suggest there is no similarity between past and present conditions.

BY SOMDATTA MAITY

PUBLISHED 6 DAYS AGO

Iceberg floating on water during daytime (Representative Cover Image Source: Pexels | Photo by Pixabay)

Antarctic Sea Ice has been a huge focus for environmental conservationists worldwide. The change in the ice has major consequences, and therefore, experts track it diligently. The changes have been erratic. Recently, a team of experts tried to make sense of the erratic conditions by trying to find similar conditions to compare for solutions, stated Phys.org. Findings regarding this pursuit have been published in Communications Earth & Environment.

The first flight of Operation Ice Bridge’s Antarctic campaign flew Oct. 16, 2009, along the Amundsen Coast. The aircraft’s downward-looking Digital Mapping System camera captured images of sea ice from an altitude of at least 20,000 feet. (Image Source: Wikimedia Commons/Photo by NASA) — The first flight of Operation Ice Bridge’s Antarctic campaign's Digital Mapping System camera captured images of sea ice from 20,000 feet. (Image Source: Wikimedia Commons | Photo by NASA)

In the last few years, several inconsistent features have been noted in Antarctic Sea Ice. The ice cover showcases more variability, with certain anomalies lasting much longer than they ever did. The change that concerned experts the most was the sea ice cover being extremely low in recent times.

The study tried to understand if such conditions were present in the past. "An important question for us is how recent extreme lows in Antarctic sea ice compare to sea-ice extent from before satellite records in the earlier part of the 20th century," Lead author, Professor Marilyn Raphael of the University of California in Los Angeles said. "We present the first monthly reconstruction for Antarctic sea-ice extent by sector and in total for the entire 20th century, to put the observed changes into historical context."

Before this analysis, only the climate conditions of the last 45 years in Antarctica had been recorded. This was not enough time to monitor longer-term climate variations. The study utilizes a novel statistical model to figure out the climate conditions that have existed in Antarctica since 1899. The model helped the team to reconstruct monthly sea-ice extents. This implies the total area covered by sea ice every month and how it expanded or decreased. For this observation, researchers took into consideration the monthly mean temperature and pressure recorded by 30 weather stations across the Southern Hemisphere from 1905 to 2020.

Antarctic mountains, pack ice and ice floes (Image Source: Wikimedia Commons/Photo by Jason Auch) — Antarctic mountains, pack ice and ice floes (Image Source: Wikimedia Commons | Photo by Jason Auch)

The results indicated that there was a higher sea-ice extent in the earlier part of the 20th century. There was a decrease noted to this extent from the 1970s. This outcome was consistent with the implications made by experts from ice core data, whaling locations, and climatological data. Furthermore, the condition of sea ice during this period did not align with its present state. "Our analysis suggests that the past long-term behavior of Antarctic sea ice can no longer be relied upon to predict its future state," said Prof Raphael. "We show that there has been a structural change in the sea ice system, manifested by increased persistence in the sea-ice extent anomalies and a strongly reduced tendency to return to the mean state."

Iceberg with attached sea ice floating near Adelaide Island, west of Antarctic Peninsula. (Image Source: Wikimedia Commons/Photo by NASA ICE) — Iceberg with attached sea ice floating near Adelaide Island, west of the Antarctic Peninsula. (Image Source: Wikimedia Commons | Photo by NASA ICE)

The study implies that the change in sea ice has been unprecedented, and analyzing the history of the area will possibly not lead to solutions that will help the sea ice recuperate. "By extending this data back more than a century, we demonstrate that the recent strange behavior of Antarctic sea ice—which includes much greater variability and year-to-year memory, as well as extreme low cover—is indeed highly unlikely over the whole 20th century and adds to growing evidence of a new physical regime," co-author Dr. Will Hobbs, of the Australian Antarctic Program Partnership at the University of Tasmania, said.