Explaining persistent hydrogen in Mars' atmosphere

The fact that the cold, dry Mars of today had flowing rivers and lakes several billion years ago has puzzled scientists for decades. Now, researchers think they have a good explanation for a warmer, wetter ancient Mars. Building on prior theories describing the Mars of yore as a hot again, cold again place, a team has determined the chemical mechanisms by which ancient Mars was able to sustain enough warmth in its early days to host water, and possibly life.

source https://www.sciencedaily.com/releases/2025/01/250128123630.htm