<P> Research , published in April 2011 , described a large deposit of frozen carbon dioxide near the south pole . Most of this deposit probably enters Mars ' atmosphere when the planet 's tilt increases . When this occurs , the atmosphere thickens , winds get stronger , and larger areas on the surface can support liquid water . Analysis of data showed that if these deposits were all changed into gas , the atmospheric pressure on Mars would double . There are three layers of these deposits ; each is capped with a 30 - meter layer of water ice that prevents the CO from sublimating into the atmosphere . In sublimation a solid material goes directly into a gas phase . These three layers are linked to periods when the atmosphere collapsed when the climate changed . </P>
studies have shown that the ice located in the south pole of mars is mostly
frozen carbon dioxide