Winter sea ice MIA, scientists convene emergency summit

Pressure ridges by Blake Mc Davitt
27 September 2023

As Antarctic sea ice extent dips towards a record winter low, Antarctica New Zealand's field support staff are monitoring and assessing fast ice conditions at Ross Island.

Antarctica’s sea ice is in dramatic decline, tracking well below any winter maximum levels observed since satellite monitoring began during the late 1970s. This is creating global headlines, with sea ice loss in the Ross Sea region being attributed to winds pushing the ice against the continent.

Concerned scientists have called an emergency summit in Wellington next week, before they head to Antarctica for the summer research season.

Antarctica has lost more sea ice than has been lost over the last 30 years in the Arctic, and thinner-than-usual sea ice caused disruptions in Antarctic operations for New Zealand and other countries in 2022.

Sea ice retreat will not disrupt this year's research season. At Scott Base, the fast ice - which is attached to the land - formed early in the season and, unlike last year, has not been affected by winds pushing it out to sea.

As of this week, field guide Blake McDavitt reports that:

  • There is hard, dry fast ice out to Cape Evans with a thickness of 2.1m, which is ‘normal’ for this time of year
  • A newer area of ice has formed from Cape Evans through to Cape Bird; its thickness has yet to measured
  • In front of Scott Base, there is second season ice; it is solid and has formed some impressive pressure ridges along Pram Point (pictured left, with White Island in the background. Photo: Blake McDavitt ).

The team has been able to get to Cape Evans across the sea ice to carry out science reconnaissance.

In 2022, Scott Base staff had to take the equipment onto the sea ice on foot for the first time because the sea ice was deemed unsafe to drive vehicles on.

New Zealand scientists call an emergency summit

Sea ice retreat and its implications topped the agenda at recent international conferences, and now New Zealand scientists are convening a panel discussion on Antarctic sea ice and climate change. The goal is to provide updates on this rapidly evolving situation, as well as highlight the potential direct and indirect implications for New Zealand.

The emergency summit will be held on Tuesday, 3 October. It consists of an online discussion session among experts, followed by an online media briefing hosted by the Science Media Centre at 2pm. Interested members of the science community are welcome to listen in on the panel discussion. There will be a public information evening at Wellington’s City Gallery, 6pm. This will be livestreamed too.

Is a 'new normal' emerging?

Antarctic sea ice has been in sharp decline in recent years and its winter maximum reached a record low this year. Ariaan Purich, CC BY-SA

Some scientists are asking if a ‘new normal’ is emerging as the world continues to warm.

The consequences could be far-reaching for Earth’s climate, because sea ice keeps the planet cooler by reflecting solar energy back into the atmosphere and insulating the ocean. Its formation also generates cold, salty water masses that drive global ocean currents.

This week The Conversation published an article, by Dr Inga Smith with colleagues from Otago and Canterbury universities, which looks at why sea ice loss couldn’t be predicted, changes in sea ice thickness, and the influence of Antarctic storms on local conditions.

The factors affecting sea ice behaviour are complex. Understanding the impacts of physical and biological interactions between the cryosphere, ocean and atmosphere is critical to inform on drivers of change and the regional and global impacts. This is one of New Zealand's strategic Antarctic research priorities

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