What Really Cooled Mars

Mars atmosphere

BBC: A meteorite reveals clues to how Mars lost its thick, carbon dioxide-rich atmosphere and became a cold, rocky desert, researchers say.

The loss of its carbon dioxide cloak is likely to have caused Mars to cool. So understanding how the CO2 was removed “could provide vital clues to how we can limit the accumulation of carbon dioxide in the Earth’s atmosphere and so reduce climate change” said Dr Tomkinson.

This article is extremely misleading. They are trying to suggest that Mars lost its carbon dioxide atmosphere, which by implication was what was keeping Mars relatively warm.

But Mars never lost its carbon dioxide “cloak”; it just got thinner. Mars’ atmosphere still is about 95% carbon dioxide. Despite this domination of CO2, there is no greenhouse effect on Mars.

It was the thinning of the atmosphere that cooled Mars. This was most likely caused by the cooling of Mars’ core and subsequent loss of its magnetic field resulting in the solar wind eroding away most of the atmosphere.

Sure, Mars lost an amount of carbon dioxide, but its ratio in the atmosphere remained essentially the same.

Chemical processes eating up a lot of carbon dioxide means little when Mars’ atmosphere, whether thick or thin, is so abundant in CO2. The thickness of its atmosphere is more significant on its surface temperature than any amount of CO2.

The point is that many people would have walked away from the BBC’s article believing that Mars was warm because of CO2, and it then became cold because the “warm” CO2 was then removed from the atmosphere. This is of course misleading and wrong.

Meteorite may explain ‘how Mars turned to stone’