Life arose on Earth at least 3. 5 billion years ago, and our planet has remained habitable ever since—not too hot, not too cold. These life-sustaining conditions are possible in part thanks to a built-in, carbon cycle–based climate "thermostat" that controls the amount of carbon dioxide in the a...
Source: [Phys.org](https://phys.org/news/2026-10-earth-thermostat-pangea-era.html)