Ancient microbes on Mars blamed for climate change

Ancient Mars may have had an environment capable of harbouring an underground world swarming with microscopic organisms, French scientists have concluded.

The Nature Astronomy journal published a climate modelling study, according to which these simple life forms would have altered the atmosphere so immensely that they activated a Martian Ice Age and brought about their own demise, as reported by the British The Week on October 12.

The theory is that the "early microbes started devouring the hydrogen and producing methane [which on Earth acts like a potent greenhouse gas]", said Space.com, and that this "slowed down" the warming greenhouse effect, "making ancient Mars gradually so cold it became inhospitable".

The study's lead author, astrobiologist Boris Sauterey, said the findings – based on computer simulations of the ancient Martian crust and hydrogen-consuming microbes like those on ancient Earth – suggest that even simple life "might actually commonly cause its own demise".

Associated Press, as reported by the Guardian, described this verdict as a "bleak view of the ways of the cosmos". Sauterey argued though that while "a bit gloomy", the findings were are "also very stimulating" because they "challenge us to rethink the way a biosphere and its planet interact".

For instance, he "believes the new work will be useful for future Mars missions", reported Inverse, "as it could help identify ideal pockets of the surface where Mars’ primitive biosphere might have survived a possible ice age".

Sauterey also "points to the team’s model as a tool to help understand if planets in our solar system and others might harbour life", the science news site added. "Rather than early life being easily self-sustaining, biospheres could enter into feedback loops that lead to their own deterioration".

However, the wider conclusions remain less rosy. The study "kind of points to the fact that potentially one of the limiting factors of the commonality of life in the universe is life itself", said Sauterey.

"Hopefully, on Earth, that tendency did not exist and was compensated by other things", he said, "but potentially it is a common fate of life in the universe to self-destruct".