A study finds atmospheric and climate conditions that could have created a cloud greenhouse effect to warm Mars and support liquid surface water. Although Mars is a cold planet in present times, receiving around 30% of Earth's solar energy, it hosted lakes and rivers of liquid water in the past. Water-ice clouds have been proposed as a possible warming mechanism on Mars. Edwin S. Kite and colleagues used a global climate model of Mars to simulate cloud greenhouse conditions that could warm the planet to temperatures that could support liquid surface water but only with spatially patchy surface water features. In the modeled results, low clouds and warm stable climates emerge when surface water-ice is found at locations much colder than average surface temperatures, whereas locations horizontally distant from surface cold patches develop high clouds, which maximize greenhouse warming. As ice particles fall, they sublimate and moisten sub-cloud layers to feed updrafts and support high clouds. The resulting climates are arid, with average relative humidity around 25%, and lakes in such a climate could be fed by groundwater upwelling or ice melting. According to the authors, the modeled results support a cloud greenhouse hypothesis for Mars and are consistent with geological data suggesting a warm, arid early climate for the planet.
Article #21-01959: "Warm early Mars surface enabled by high-altitude water ice clouds," by Edwin S. Kite, Liam J. Steele, Michael A. Mischna, Mark I. Richardson.
MEDIA CONTACT: Edwin S. Kite, University of Chicago, IL; tel: 510-717-5205; email: <email@example.com>
Proceedings of the National Academy of Sciences