Antarctic sea ice falls to near-record low as study reveals 'structural change'

A recent study indicates that Antarctic sea ice extent has once again fallen to near historical lows, suggesting the system is undergoing significant "structural change." Scientists have been tracking the extent of sea ice around the Antarctic continent's edges using satellite imagery for the past 45 years.

According to data from the Australian Antarctic Program Partnership (AAPP), sea ice extent has fallen below 2 million square kilometers four times during this period: in 2022, 2023, 2024, and 2025. The organization stated that the data from March 1st of this year represents the third-lowest annual daily minimum on record.

AAPP sea ice researcher Will Hobbs of the University of Tasmania stated that the observed downward trend since around 2016 includes recent recurring lows. "The worrying thing is that we're no longer worried, because this has become the new normal," Dr. Hobbs said. He added, "Another very low summer sea ice extent is no longer surprising to us, because we've seen it happen in a row. It is really concerning that we're seeing this long-term structural change."

Dr. Hobbs is a member of an international research team that recently used a novel method to determine the extent of Antarctic sea ice before satellite records. He said, "Obviously, we don't have a time machine, but what we can do is do what's called a 'reconstruction'." Sea ice fluctuates significantly between summer and winter and is heavily influenced by atmospheric conditions, including temperature, wind speed, and wind direction. Dr. Hobbs said, "Antarctic sea ice has historically been very atmospherically driven. If we can reconstruct what the atmosphere was doing in the early 20th century, then we can perhaps infer what the sea ice was doing."

Using historical data from 30 meteorological stations in the Southern Hemisphere, the team was able to "reconstruct" the likely extent of Antarctic sea ice back to 1899. Professor Marilyn Raphael of UCLA said, "This allows us to understand the context of the extreme variability of Antarctic sea ice." The results showed that the extreme minimums seen in recent years would have occurred less than one in a thousand times in the 20th century. "The system has changed," Professor Raphael said, "and it's changed from a situation where we can normally look at [long-term] averages... and have an understanding of what's going to happen. We can no longer look at our averages, because we've moved into an extreme system."

Dr. Hobbs indicated that recent low sea ice levels may be related to rising ocean temperatures. He said, "The atmosphere alone is not enough to explain what we're seeing. The ocean must be playing a role." He stated that further research is needed to better understand the causes and impacts of changes in the Southern Ocean. Dr. Hobbs said, "Either anthropogenic climate change has caused ocean changes that are driving these events, or this kind of ocean event has happened in the past [before 1899]."

Dr. Hobbs stated that low Antarctic sea ice levels could have significant ripple effects, including reduced protection for ice shelves and glaciers, which could lead to sea-level rise if they melt. He said, "This could be a global problem." The study, titled "Structural change in the Antarctic sea ice system in the twenty-first century," has been published in the journal *Nature Communications Earth & Environment*.