# A precious piece of sediment, and what it says about our future

An episode of [Our Changing World](https://invisiblenetwork.ai/podcast/208013620), 17 Aug 2026, 31 min.

Audio: https://flex.acast.com/media.rnztools.nz/rnz-kete-oro-prod/video/private/ac_mp3,af_48000,br_192k,f_mp3,fl_attachment/v1786496662/audio/ocw/ocw-20260818-0500-a_precious_piece_of_sediment_and_what_it_says_about_our_future.mp3

After years of preparation and effort an international team have succeeded in recovering over 200 metres of sediment from below the West Antarctic Ice Sheet. Claire Concannon visits the sediment core analysis team in Dunedin to find out how mud, rocks and microfossils can tell the story of ice growth and retreat across time. And as we look towards our warmer future, what will this mean for sea level rise? Sign up to the Our Changing World monthly newsletter for episode backstories, science analysis and more. In this episode: (00:00) Introduction to Antarctica, the West Antarctic Ice Sheet and the SWAIS2C drilling project. (02:18) Recovering a sediment core from beneath 523 metres of ice at Crary Ice Rise. (04:00) Professor Richard Levy on the early steps of processing the core (07:50) Sedimentologist Georgia Grant explains how rocks reveal the advance and retreat of ancient ice sheets. (14:33) Dating the core using paleomagnetism and microscopic fossils such as diatoms. (22:45) Evidence for past periods of open water and warmer climates in West Antarctica. (25:40) The co-chief scientists on what the findings mean… Go to this episode on rnz.co.nz for more details

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