800,000 YEARS OF AIR

Scientists dug a hole to the bottom of Antarctica and they pulled up this ice core. And it shows our atmosphere from 800,000 years ago. They dug it up right here where it's so cold that the ice just piles up and up and up and up and up, trapping bits of history inside, creating layers like this that can be counted like tree rings. What's most interesting is each of these layers is full of gas bubbles that hold gases from that period's atmosphere. So every layer is like a time capsule. Once a core is pulled up, researchers slice it, then crush or melt it to prevent contamination. This releases those ancient gas bubbles so they can analyze them, which is how this chart was made, showing how levels of CO2 in our atmosphere have changed over time. And then in 2025, they pulled up one that goes even farther, 1.2 million years. 1.2 million years. To see that, follow along.