How exploring Mars could help us fight climate change on Earth

21.08.2023 - 11:55 / theunconventionalgardener.com / guest

Adrienne Macartney, University of Glasgow

The surface of Mars is a cold desert. Scars in the landscape point to a history of flowing rivers, standing lakes and possibly even planetary oceans. Yet the current Martian atmosphere has a density that’s around 0.6% of Earth’s, making it far too thin to support liquid water – or life – on the barren surface.

At some point in the planet’s history, however, there must have been a thicker, denser atmosphere, probably dominated by carbon dioxide (CO2). And working out what happened to all that CO2 could help us deal with the increasing amount of the gas in our own atmosphere, which is pushing us towards dangerous climate change.

So where did the Martian atmosphere go? A large amount was lost to space, stripped away by the solar wind. Some has been stored as CO2 ice at the poles, where it remains today. But part of the atmosphere was transformed into carbonate minerals and preserved through the millennia. Using a combination of satellites and rovers, as well as evidence from meteorites that have been ejected from Mars and landed on Earth, we are beginning to understand how this process of mineral carbonation can change an entire planet’s atmosphere.

Humanity has actually become very good at capturing CO2 from the atmosphere through a wide variety of techniques. Once captured, the CO2 is usually compressed into a dense liquid. The problem comes in storing this liquid safely and stably, over millions of years. One exciting new development is called “mineral carbon sequestration”. This is the process of transforming CO2 gas into a stable mineral called carbonate.

How does CO2 gas become solid rock? If CO2 gas dissolves in water it produces a weak acid, called carbonic acid. When this