What can the world’s biggest iceberg tell us?

世界上最大的冰山能告诉我们什么?

The Inquiry

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2024-05-30

23 分钟
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The current record holder for the world’s biggest iceberg is the A23a. Back in 1986 this colossus broke away from an Antarctic ice sheet. This process of breaking off or ‘calving’ as it is known is a natural part of the life cycle of an ice sheet. But A23a then became lodged in the Weddell Sea for more than thirty years, until four years ago a gradual melting allowed the berg to refloat. Since then it’s been steadily on the move, heading in the same direction as Antarctic icebergs before it, towards the warm waters of the Southern Ocean, where it will eventually shrink from melting. As it travels, the iceberg has been playing an important role on the ecological environment around it, both in positive and negative ways. So, on this week on The Inquiry, we’re asking ‘What can the world’s biggest iceberg tell us?’ Contributors: Dr. Catherine Walker, Glaciologist, Woods Hole Oceanographic Institution, Massachusetts, USA Dr. Oliver Marsh, Glaciologist, British Antarctic Survey, Cambridge, UK Jemma Wadham, Professor of Glaciology, UiT The Arctic University of Norway Christopher Shuman, Research Associate Professor, NASA Goddard Space Flight Centre, Maryland, USA Presenter: William Crawley Producer: Jill Collins Researcher: Katie Morgan Editor: Tara McDermott Production Co-ordinator: Ellie Dover Image Credit: A23a in Antarctica, Jan 2024. Rob Suisted/Reuters/via BBC Images

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  • Welcome to the Inquiry.

  • I'm William Crawley.

  • Each week, one question, four expert witnesses, and an answer.

  • An iceberg is on the move.

  • But this is no ordinary iceberg.

  • It's a floating colossus, the biggest iceberg currently at sea.

  • Known as a 23A, it broke away from an ice shelf on the Antarctic more than 35 years ago before becoming stuck in the Southern Ocean.

  • But in 2020, that decades long stillness was broken.

  • And now a trillion tons of frozen pure water is riding the currents of Iceberg Alley.

  • So this week we're asking, what can the world's biggest iceberg tell us?

  • Part one, Birthing.

  • An iceberg is a piece of ice that's broken off from one of our two ice sheets on the Earth.

  • So there's the Antarctic ice sheet and the Greenland ice sheet and sometimes smaller glaciers that exist around the coast of places like Canada and Russia.

  • Dr.

  • Catherine Walker is a glaciologist with the Woods Hole Oceanographic Institution in Massachusetts in the United States.

  • And like any material, those tend to break off into chunks when they get to a certain stress level.