Sulfur Dioxide May Have Helped Maintain A Warm Early Mars

Sulfur dioxide may have played a key role in the development in the climate and geochemistry of early mars, current evidence suggests. This provide a possible mechanism to explain why the planet is so much colder than it is believed to have been in the past. There is abundant evidence that huge Martian oceans were present on the much warmer planet from 3-4 billion years ago, although scientists found it difficult to determine how regulation occurred as it seemed to vary from the patterns seen here on Earth. On Earth, everything is controlled by the carbon cycle which recycles carbon dioxide between volcanoes and interaction in the surface rocks of the planet. There is not enough active volcanoes on the surface of Mars to maintain this cycle, currently, but there is evidence that there was enough activity billions of years ago to suggest that a carbon cycle on Mars could have played a key role in the development of its climate. The high levels of sulfur and limestone on Mars are one possible explanation as to why there is so little carbon dioxide present on the planet today.

http://www.marsdaily.com/reports/Sulfur_Dioxide_May_Have_Helped_Maintain_A_Warm_Early_Mars_999.html