Scientists Reconstructed Antarctic Polynya History
A new 122-metre ice core analysis uncovered 250 years of data on rare open-ocean leads in the Southern Ocean.
Updated on Sept. 29, 2026 in Environmental
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Researchers have reconstructed 250 years of history regarding the Maud Rise Polynya using a 122-metre ice core extracted from Dronning Maud Land. The study identified 25 potential opening events in the Weddell Sea between 1774 and 2016, providing insight into phenomena that predated modern satellite observation.
Why it matters
Understanding the long-term history of these massive ocean openings helps scientists determine how climate change may influence Southern Ocean convection. These events, which cause deep water to rise and release heat, remain critical for modeling future Antarctic sea-ice extent.
The study utilized a 122-metre ice core, combining sea-salt sodium flux, oxygen isotope ratios, and deuterium excess to create a polynya index. Researchers identified 25 events, including a 300,000 sq km opening that triggered convection at depths of 3,000 metres.
The players
Maud Rise Polynya
This is a recurring area of open water surrounded by sea ice in the Weddell Sea that allows for intense heat exchange between the deep ocean and the atmosphere.
The details
By using annual layer counting and dated markers, scientists established a chronology that covers the period from 1774 to 2016. The data highlights a suppressed period of activity between 1920 and 1950, followed by significant openings in 1974-1976 and the modern reappearance in 2016-2017.
Timeline
1774-2016: The total period analyzed via ice core reconstruction.
1920-1950: A documented interval of suppressed polynya activity.
1974-1976: The period of peak Maud Rise Polynya activity.
2016-2017: The most recent observed reappearance of polynya openings.
The Big Picture
This research extends our understanding of the historical satellite-era Antarctic sea-ice record by providing proxy data for events occurring long before modern remote sensing existed. The findings offer a new theoretical framework for predicting how shifting wind and ice conditions alter deep ocean circulation.
This research enhances our ability to model future climate change by clarifying how the Southern Ocean regulates heat through deep-water convection. These findings improve the accuracy of global climate simulations, which eventually inform future environmental policy and resource management strategies.
The takeaway
The study demonstrates that Antarctica's open-ocean leads have experienced significant fluctuations in frequency and size over the last two and a half centuries. Researchers suggest that future changes in wind patterns will likely determine whether these massive polynyas become more frequent as the planet warms.
Further reading
Learn more about climate research in our Environmental section.
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