# Exoplanets Without Lots of Water Cant Maintain Their Carbon Cycles

- slug: exoplanets-without-lots-of-water-cant-maintain-their-carbon-cycles
- date: 2026-04-20
- category: Space & Aerospace

Earth may be the rare water-rich outlier, not the template. New research puts a number on the minimum ocean mass an arid planet needs to sustain its climate: 20 to 50 percent of Earths. Below that, even worlds in the habitable zone can go Venus-mode.

---