Our Changing World

Cold plunges and cold water swimming are increasingly popular, with big benefit claims being made on social media. But is submerging yourself in frigid water actually good for you? Claire Concannon joins a team of researchers at the 2026 New Zealand and Oceania Ice Swimming Championships in Alexandra as they try to get some better data about both the risks and potential benefits.

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IN THIS EPISODE:
(00:00) Introduction – the rise of cold water swimming.
(01:06) The 2026 New Zealand and Oceania Ice Swimming Championships in Alexandra.
(02:00) Competitor Susan Sherwen on why she ice swims.
(05:10) How researchers track swimmers’ core temperature, stroke rate and perceptions of cold.
(07:30) Prof Jim Cotter on cold shock, hypothermia and afterdrop.
(12:00) The recovery room – Steven and Susan after their swim.
(17:30) Potential benefits and what the research says.
(20:30) Blood samples and looking for brain health proteins.
(23:40) Potential mental health benefits…
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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?
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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…
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There’s a lot of chat about solar panels for our rooftops, but where else might it make sense to put them? Claire Concannon visits the University of Canterbury’s Electric Power Engineering Centre to learn about their involvement in a big European project exploring the use of solar panels on vehicles and in car parks. Plus, she speaks to one researcher who is focused on planning for global catastrophes.
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At the Robinson Research Institute in Wellington, researchers are developing powerful superconducting magnets for space, fusion and MRI applications. Claire Concannon visits the labs to learn about a small magnet’s trip to the International Space Station, and how much bigger magnets are powering nuclear fusion research. She also meets the team working on a hydrogen-based way to make iron from New Zealand iron sand, removing carbon dioxide emissions from the first step of steelmaking.

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In this episode:
(00:00) Professor Nick Long on watching the Hēki magnet arrive at the International Space Station
(04:20) Dr Nick Strickland on making superconducting magnets robust and useful
(08:38) Fusion magnets and future research questions for Open Star Technologies
(11:05) Professor Chris Bumby on why steelmaking produces carbon dioxide
(15:20) Ben Rumsey on hydrogen reactors and producing direct reduced iron
(19:50) Cullbeck Limited and plans to scale up the process
(23:10) How the New Zealand Institute for Advanced Technology works…
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To get electric passenger planes in the skies requires powerful electric motors, but they must also be small and light. Some kiwi scientists think they could have a solution. Claire Concannon heads to a warehouse in Petone to learn about the promise of high temperature superconducting magnets to make electric motors for airplanes.
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In this episode:
00:00 - Where are our electric planes?
01:00 - The challenge of aviation electrification.
02:48 - The history of the Robinson Research Institute and useful properties of superconductors.
07:00 - The establishment of the New Zealand Institute of Advanced Technology
08:30 - The advantage of superconducting motors for aviation.
11:15 - Airbus’ plans for a future electric plane
12:05 - Warehouse tour and levitation bearings for future motors
14:04 - Basic motor design and characterising AC losses in superconductors.
21:26 - Testing a superconducting generator with Air New Zealand…
Go to this episode on rnz.co.nz for more details