7 Feb 2024

Our Changing World – How much more heat can West Antarctica take?

From Afternoons, 3:35 pm on 7 February 2024
A large half-cylinder tent next to a radio pole and an assortment of equipment.

The SWAIS2C team spent a month camped at the edge of the West Antarctic Ice Sheet, where it begins to float as the Ross Ice Shelf. Pictured is the drilling tent. Photo: Anthony Powell / Antarctica NZ

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Antarctica is losing ice at an accelerating rate, particularly in some parts of West Antarctica.

How has the small and less stable West Antarctic Ice Sheet behaved during past periods of natural warming? Geological evidence is sparse, but an ambitious sediment-drilling project that kicked off this summer aims to change that. 

Drilling back in time to explore past periods of warming

SWAIS2C – short for Sensitivity of the West Antarctic Ice Sheet to 2 °C – is an international collaboration, co-led by Aotearoa New Zealand. During its first season this summer, the team set up camp close to the grounding line of the Ross Ice Shelf, where the world’s largest slab of floating ice is at its thickest. Below more than 580 metres of ice, only about 50 metres of ocean separate the bottom of the ice from the ocean floor.

The team used hot water to thaw a hole through the ice to reach the seafloor where layers of mud and rock have been accumulating for millennia, building up one of Earth’s memory banks of environmental conditions at the time they were deposited.

The SWAIS2C team successfully retrieved the longest sediment core ever extracted from the remote Siple Coast, which holds clues about the ice sheet’s more recent past. Next season, the team hopes to drill deeper and further back in time to the last interglacial period, some 125,000 years ago, when Earth was around 1.5 °C warmer than pre-industrial temperatures – similar to the warming we are approaching now.

Listen to the episode to learn more about the challenges of hot water drilling in this remote part of Antarctica.

Nine people in two rows wearing warm clothes, sunglasses and beanies stand in front of a small white hut on the ice beneath a blue sky. The man in the middle is holding a long cylinder that is taller than him.

The coring team. Photo: Anthony Powell / Antarctica NZ

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