Unprecedented Decline In Antarctic Sea Ice


  • Dr. Babula Jena and colleagues from the National Centre for Polar and Ocean Research (NCPOR) collaborated with the British Antarctic Survey to study the delays in Antarctic sea ice expansion and the ice retreat observed in the annual ice maximum of 2023.
  • While the Arctic has experienced significant sea ice loss over the past decade due to global warming, the Antarctic showed a slight increase in sea ice until 2015, followed by a marked decline starting in 2016.
  • The decline in Antarctic sea ice has been consistent, with extremely low conditions each summer from 2016 to 2023. In 2023, the ice expansion was notably slow, culminating in an ice extent on September 7 that was 1.46 million km² below the long-term average.
  • The study highlights excessive upper-ocean heat and significant atmospheric circulation changes as primary factors restricting ice expansion in 2023. Notable changes include the deepening and eastward shift of the Amundsen Sea Low, causing substantial northerly flows that kept the ice edge south of its usual position.

Antarctic Ice Expansion and Retreat in 2023

In a recent study conducted by Dr. Babula Jena and coworkers from the National Centre for Polar and Ocean Research (NCPOR), in association with the British Antarctic Survey, researchers delved into the conditions that are causing unprecedented delays in Antarctic Ice Expansion and ice retreat of the annual ice maximum in 2023.

The Arctic has lost significant sea ice over the last decade due to global warming, whilst the Antarctic saw a mild growth until 2015, followed by a sharp decline since 2016.

This decline continued with extremely low sea ice conditions observed every summer between 2016 and 2023.

In 2023, there was an unprecedented slow ice expansion or retreat before the annual maximum on September 7, with an ice extent of 16.98 million km2, 1.46 million km2 less than the long-term average.

Atmospheric Shifts on Antarctic Ice Patterns

The analysis highlights the impact of excessive upper-ocean heat and significant atmospheric circulation changes on limiting ice expansion in 2023.

These changes, particularly the deepening of the Amundsen Sea Low and its eastward shift, resulted in significant northerly flow across the Weddell Sea, keeping the ice edge south of its regular position.

The Ross Sea also underwent rapid ice extent changes due to the record-breaking strengthening of an air block, which caused strong northerly winds off the Ross Ice Shelf.

The consequences of unprecedented ocean-atmospheric warming, wind shifts, heat fluxes, severe winds, and high ocean waves associated with polar storms contributed to Antarctica’s record low ice cover.

Cyclones caused extremely slow ice expansion or retreat, such as the ice edge in the Weddell Sea rapidly moving southward, resulting in significant ice area loss.

Analyzing the Role of Cyclones in Antarctic Ice

These low ice conditions are expected to have various effects, including increased global warming through the ice-albedo feedback cycle, ice shelf stability, ocean circulation, the southern Ocean’s ecosystem, and sea level rise.

Despite satellite observations spanning only about 45 years, it is difficult to assess the decrease in ice extent over the last seven years and the current reduction in ice growth as part of a long-term decline, as projected by climate models.

Both natural climate variability and anthropogenic factors play essential roles.

Further research is needed to understand the connection between the region’s anthropogenic forcing and climatic variability.

The National Centre for Polar and Ocean Research (NCPOR), part of the Ministry of Earth Sciences, leads India’s polar and Ocean research.

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Source: marineinsight