Earth can sustain life for another 100 million years, but can we? This episode, we partner with Radiolab to take stock of the essential raw materials that enable us to live as we do here on Earth — everything from sand to copper to oil — and tally up how much we have left. Are we living with reckless abandon? And if so, is there even a way to stop? A simultaneously terrifying and delightful conversation about bird poop, daredevil drivers, and some staggering back-of-the-envelope math. Radiolab's original episode was produced and edited by Pat Walters and Soren Wheeler. Fact-checking by Natalie Middleton. The Planet Money edition of this episode was produced by Emma Peaslee and edited by Alex Goldmark and Jess Jiang. Special thanks to Jennifer Brandel.Find more Planet Money: Facebook / Instagram / TikTok / Our weekly Newsletter.Listen free at these links: Apple Podcasts, Spotify, the NPR app or anywhere you get podcasts.Help support Planet Money and hear our bonus episodes by subscribing to Planet Money+ in Apple Podcasts or at plus.npr.org/planetmoney.Music: NPR Source Audio - "Wir Rollen" Learn more about sponsor message choices: podcastchoices.com/adchoicesNPR Privacy Policy
Chapter 1: What is the main question about economic growth?
A few weeks ago, we got this kind of mind-bending question. It was from our friends at Radiolab, which is a show about science and philosophy and, you know, just the sheer joy of curiosity. In this case, they were curious about growth, in particular, economic growth. How could it possibly go on forever? And can too much growth destroy us?
And in trying to answer their big question, we ended up in some pretty heady and unexpected places. Hello and welcome to Planet Money. I'm Jeff Guo. And today we're doing something a little bit different. We've teamed up with Radiolab and we're going to try to answer one of the biggest questions that often goes unsaid in economics. Here's Latif Nasser from Radiolab to get us started.
Chapter 2: Why is an astrophysicist discussing economic growth?
Hey, this is Radiolab. I'm Latif Nasser. What got me thinking about economic growth was not all the stuff that's in the news, the tariffs, the fear of the recession, all that stuff that everybody's talking about. What started it was a lecture I heard a little while back by, of all people, an astrophysicist.
So I'm going to sketch what we know about Earth's history, cosmically speaking.
Her name is Sandra Faber. She goes by Sandy. Brilliant scientist. She co-authored the Standard Model for Thinking About How Galaxies Form. She won a National Medal of Science back in 2011. And she started the lecture by saying, we have a pretty happy little planet to live on.
Earth is a good place to live for, let's say of order, 100 million years at least.
Should be livable for a really, really long time. Okay.
Except, she goes on to say, for us.
Over the last century or so. We've been seeing planet-wide GDP growing exponentially.
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Chapter 3: How fast are we consuming Earth's resources?
So what she did is she took the average gross domestic product worldwide, and that's a rough measure of economic growth, and that had been growing recently around 3%, which for economists is like a happy little growth number.
You will recognize 1.03, 3% as the...
But Sandra took that 3%. And with some quick math, she started to just play it out year after year. And in her lecture, she's showing this chart where you can see this curve just shooting up.
We can see this number is completely ridiculous. This is.
And she was basically like, look at all that growth. That's eating up Earth's resources.
A large number here is bad because it means that we want more of that product.
And so even though Earth should be good for 100 million years, we're going to just eat the planet up. We're going to devour the physical, material level of this planet. We're going to eat it up in more like a couple thousand years.
And my concern is that we're not talking about this.
And when I heard that, that was breathtaking and horrifying. And honestly, I haven't been able to stop thinking about that number, 3%. It sounds like a specific thing, but also it's kind of abstract and mathy, and I wanted help. I wanted help to parse this out. Like, how bad is that really? How bad could that possibly be?
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Chapter 4: What materials are we at risk of running out of?
Okay. Well, I mean, I guess where I would start is, and, you know, I would hate to contradict a Nobel Prize winning astrophysicist. It sounds like, you know, starting out on dangerous territory there.
I mean, well, she won the National Medal of Science, not the Nobel.
She's going to. She's going to. It sounds like she's going to win.
Okay. Yeah, sure. Fair.
But you did ask me to kind of look into what things are we going to run out of.
Yes, yes, yes. Oh, my gosh. I'm so excited.
after the break can we cure Latif's existential dread or did we just make it worse Okay, Latif, so I looked into your question about growth and stuff that we might run out of, and I found a couple things that, you know, people are worried about. Okay, great. And I just did some very rough back-of-the-envelope math. Like, this is so totally not precise.
My favorite kind of math. My favorite kind of math. It's so hand-wavy.
Great. I love it. Okay, so I don't know. What should we start with? Copper? Copper.
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Chapter 5: Could sand really become scarce?
Yeah.
Yeah. So if you just, you know, extrapolate that out, if you just assume copper is going to keep growing at 3% every single year, right? Fair. Fair assumption. I looked up how much copper people think we have. According to geologists, what we know is out there and could theoretically get to. And that number right now is 5 to 6 billion tons. Okay.
It's not nothing, but we're using it pretty quickly. And if you just assume that this number is going to keep growing at 3% a year... Yeah, yeah, sure. It would take about maybe another 70 years. And then no more copper. That's it? 70 years? 70 years. Oh, okay, so that sounds terrible. It's true. It's true. That's assuming, of course, that... You know, we do keep consuming copper that quickly.
Using copper and needing copper the same way that we are. Yeah, yeah, sure. T minus 70.
Yeah.
No copper for anybody.
No copper.
Okay. Okay. So then what, but then, so that's, this seems to point exactly to Sandy Faber's point, right?
It's true. It's true. It's true. Yeah. Do you want to do another one?
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Chapter 6: What is the future of lithium and oil consumption?
Totally. So I looked it up, and according to geologists, the Earth's crust, all of the Earth's crust contains... maybe like 23 quintillion tons of rock and stuff. Okay.
Okay. But it does seem like the whole point of sand is that it's like teeny tiny. It would take a lot of energy to turn that rock into sand.
It would. But assuming that we're able to do that, right? Okay, great. Assuming that we're going to use sand and gravel at a rate that grows by 3% every year, year after year after year. Yeah. It would take about, do you want to guess how long it would take to deplete the entire Earth's crust?
Wait, so a quintillion based on the growth rate and the uses now. I would imagine this one is going to be, this one is not on Sandra Faber's side. I'm going to guess this one is like way, way, way far from now. Like this is going to be like a million years or something.
Five to 600 years.
That seems so short again. It does, doesn't it? That is way shorter for the whole crust.
I know.
Oh, my God. That's not... Like, it's long, but it's not that long. Like, that's like... That is nuts.
All right. I got a couple more.
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Chapter 7: How did historical shortages influence innovation?
So geologists think that of all the lithium that we know is out there, there's probably like 105 million tons of it, like out there.
That sounds... A lot less than the sand. Like, this doesn't sound—this is going to get worrying. Okay, keep going.
Right. And so, you know, if you do this whole, you know, the same math, and you just—if you assume—if you just assume, just, you know, for the sake of argument, it's only going to grow at 3% a year, right?
Yeah, sure.
We'd probably run out of lithium around— March.
I feel like you're going to say, like, I feel like you're going to say, like, so soon. Tomorrow.
About 100 years.
Okay, 100 years again. Which is not bad. No, it is bad. It's bad, Jeff. It's bad. We need that. Like, we're going to need that later for even better stuff.
It's true.
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