Science Alert By Ben Turner 14 October 2022
Ancient microbial life on Mars could have destroyed the planet's atmosphere through climate change, which ultimately led to its extinction, new research has suggested.
The new theory comes from a climate modeling study that simulated hydrogen-consuming, methane-producing microbes living on Mars roughly 3.7 billion years ago. At the time, atmospheric conditions were similar to those that existed on ancient Earth during the same period.
So as ancient Martian microbes ate hydrogen (a potent greenhouse gas) and produced methane (a significant greenhouse gas on Earth but less potent than hydrogen) they slowly ate into their planet's heat-trapping blanket, eventually making Mars so cold that it could no longer evolve complex life.
More:
https://www.sciencealert.com/earliest-life-on-mars-could-have-self-destructed-in-a-climate-catastrophe