Mars cooling provides climate change insight
23 October 2013, by Harriet Jarlett
Scientists have shown for the first time that Mars may have lost its carbon dioxide (CO2)-rich atmosphere in a process that could be used to curb global warming on Earth.
False colour image of the Lafayette meteorite showing carbonate (orange) replacing olivine (blue).
4,000 million years ago, Mars was believed to have been a warm and wet planet with a thick atmosphere which was rich in CO2 – a greenhouse gas that on Earth is contributing to rising global temperatures.
However, over time, it's thought that Mars lost this gas, helping to cool the planet and resulting in the cold and arid Martian environment we observe today.
A study, published today in Nature Communications, provides the first evidence that a process called carbonation potentially played a major role in the loss of Mars' early atmosphere.
Carbonation is a reaction in which rocks containing volcanic minerals such as olivine react with water and atmospheric CO2 to turn it into another mineral, called carbonate. During this process, CO2 becomes trapped in the carbonate, removing it from the atmosphere permanently.
The research was conducted using pieces of a meteorite called Lafayette, which fell to Earth around 3,000 years ago. 'Lafayette was previously known to contain carbonate, but this is the first evidence that it formed by carbonation' explains Dr Tim Tomkinson of the Scottish Universities Environmental Research Centre (SUERC), lead author of the paper.
Carbonation is already known to occur in certain locations on Earth. But by studying the fine-scale processes of how CO2 was trapped within Martian rocks, the researchers hope their study could provide an insight into reducing CO2 in our own atmosphere.
'On Earth, we have the problem of where to store increasing levels of atmospheric carbon dioxide contributing to global warming. However, for decades researchers have been questioning where all the ancient carbon dioxide in Mars' atmosphere has gone,' says Tomkinson.
'This discovery is significant in terms of the way in which scientists will study Mars in the future but also in providing us with vital clues of how we can limit the accumulation of carbon dioxide in the Earth's atmosphere and so reduce climate change,' he concludes.
Tim Tomkinson, Martin R. Lee, Darren F. Mark & Caroline L. Smith, Sequestration of Martian CO2 by mineral carbonation, Nature Communications 4, Article number: 2662, published 22 October 2013, doi: 10.1038/ncomms3662
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