The Math of Catastrophe
The Quanta Podcast
Quanta Magazine
4.7 • 638 Ratings
🗓️ 14 October 2025
⏱️ 28 minutes
🧾️ Download transcript
Summary
Around 6,000 years ago, the Sahara was a lush grassland. Then, as if a switch flipped, it began to dry out, becoming the desert that we know today. Tipping points are moments in Earth’s history where gradual change suddenly becomes rapid and forms a new equilibrium.
They’re one of the most alarming threats of our planet’s near future — and one of the most uncertain.
When will a tipping point occur? Mathematicians are attempting to turn vague, apocalyptic visions into something that we can actually prepare for and deal with. On this week’s episode, host Samir Patel speaks with contributing writer Gregory Barber about what tipping points can — and cannot — tell us about the future of our planet. This topic was covered in a recent story for Quanta Magazine.
Each week on The Quanta Podcast, Quanta Magazine editor in chief Samir Patel speaks with the people behind the award-winning publication to navigate through some of the most important and mind-expanding questions in science and math.
Audio coda courtesy of Gresham College.
Transcript
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| 0:00.0 | Around 6,000 years ago, human cultures across the world were developing a lot of what came |
| 0:09.5 | to be associated with complex societies, metallurgy, agriculture, long-distance trade networks, |
| 0:17.5 | early writing, cities. |
| 0:19.7 | And for thousands of years, by that point, since the end of the last |
| 0:22.8 | glacial maximum, the Sahara was a lush grassland covered in lakes and rivers and herds of |
| 0:30.9 | animals and lots of people. Around that time, though, something was naturally shifting in Earth's |
| 0:37.1 | climate, an orbital cycle, actually. |
| 0:39.9 | And that changed the monsoon patterns in Western Africa, and we know the rest. It dried out, |
| 0:46.4 | pushing people toward the Nile Valley, where Ferronic Egypt was about to rise and rendering a huge |
| 0:52.2 | swath of Africa, more or less uninhabitable. |
| 0:55.9 | Now, it took time, but it went from one state to another, like a switch had flipped. |
| 1:01.3 | I think you might know where we're going with this. |
| 1:03.8 | As much as we're altering Earth's climate ourselves now, what else can flip? |
| 1:16.1 | Thank you. now, what else can flip? Welcome to the Quanta podcast where we explore the frontiers of fundamental science and math. |
| 1:20.7 | I'm Samir Patel, editor-in-chief of Quantum Magazine. |
| 1:23.8 | When we assembled our recent special issue on climate, called How We Came to Know Earth, |
| 1:29.3 | we wanted to make a place for math in the series. |
| 1:32.3 | There's all sorts of math involved in climate change, but there was a subject that stood out to us, |
| 1:37.3 | what they called tipping points, where a gradual change might suddenly become a rapid one and form a new equilibrium. They're one of the most |
| 1:47.6 | alarming parts of trying to understand what's going to happen to our planet next. So we ask |
| 1:53.3 | science and tech journalist and one of our go-to math writers, Greg Barber, to look into it. |
| 1:58.8 | He's here to talk to us today about the story that he wrote. It's called |
... |
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