Conversation

Mars is cold and dry today, but it was warmer and wetter billions of years ago, with flowing lakes and rivers. The Sun was fainter then, deepening the mystery. Researchers have long believed that atmospheric hydrogen was the key, mixing with carbon dioxide to provide a greenhouse effect. But atmospheric hydrogen is short-lived, so what was replenishing it? A new paper finds that warm periods were driven by crustal hydration, building hydrogen in the atmosphere.

https://seas.harvard.edu/news/2025/01/explaining-persistent-hydrogen-mars-atmosphere