> [!cite] > Silberry, Jeff, dir. *ABC iview*. Episode 1, “Megafauna: What Killed Australia’s Giants?” 12 February 2025. ABC iview. [https://iview.abc.net.au/show/megafauna-what-killed-australia-s-giants](https://iview.abc.net.au/show/megafauna-what-killed-australia-s-giants). > [!abstract] > Australia was once home to a group of extraordinary animals known as Megafauna. What became of them has been debated for over a century, but now a team of scientists are re-opening this paleolithic cold case. --- ‘We looked at the atmospheric radiocarbon signature through the time period that this tree lived, and what we can see is an enrichment of radiocarbon, that spikes quite significantly to nearly 800 per mil. That’s the strongest radiocarbon signature that we have at any time in the last 50,000 years.’ [[Silberry, Megafauna, 2024|(Silberry 2024, ep. 1; quoting Andrew Lorrey)]] ^b9a03e ‘This ancient kauri represents the truest reflection of atmospheric radiocarbon that we have on the planet.’ [[Silberry, Megafauna, 2024|(Silberry 2024, ep. 1; quoting Andrew Lorrey)]] ![[ABC iView - 'Who Killed Australia's Giants', Episode 1, 42m34s.png]] [[Silberry, Megafauna, 2024|(Silberry 2024, ep. 1; 42:34)]] ^b13104 ‘Megafauna \[…] lived in Australia for millions of years, surviving repeated climate changes throughout the fluctuating ice ages. So what could have made the environmental changes 40 to 50,000 years ago so different that many species were wiped off the face of the Earth? There’s an extraordinary geological phenomenon that some scientists now believe may have been the final nail in the coffin.’ [[Silberry, Megafauna, 2024|(Silberry 2024, ep. 1)]] ^538bca ‘So it was only about three or four years ago, I was having a really detailed conversation with a great colleague of mine, complaining that I could see these major changes in the animals and megafauna and Australia all around 42,000 years. What was happening? Why was it all happening then? And he said, “Well, the only thing that happens 42,000 years ago in the geological record is the Laschamp excursion.” And I was like, “What’s that?”’ [[Silberry, Megafauna, 2024|(Silberry 2024, ep. 1; quoting Andrew Lorrey)]] ^b09966 Alan Cooper says penetrating ionising radiation would have caused: enormous damage to the ozone layer (probably removes it entirely); ultraviolet coming in; major climactic shifts due to significantly increased build-up of cloud cover (because of ionisation in the atmosphere) = significant sudden cooling and drying. [[Silberry, Megafauna, 2024|(Silberry 2024, ep. 1; quoting Alan Cooper)]] ^5fcd84