title: Observational evidence for an active surface reservoir of solid carbon  dioxide on Mars.
abstract: High-resolution images of the south polar residual cap of Mars acquired in 1999 and 2001 show changes in the configuration of pits, intervening ridges, and isolated mounds. Escarpments have retreated 1 to 3 meters in 1 martian year, changes that are an order of magnitude larger than can be explained by the sublimation of water ice, but close to what is expected for sublimation of carbon dioxide ice. These observations support a 35-year-old conjecture that Mars has a large surface reservoir of solid carbon dioxide. The erosion implies that this reservoir is not in equilibrium with the present environment and that global climate change is occurring on Mars.
authors.affiliation: Malin Space Science Systems, Post Office Box 910148, SanDiego, CA 92191-0148, USA.
authors.forename: M C
authors.initials: MC
authors.lastname: Malin
authors.forename: M A
authors.initials: MA
authors.lastname: Caplinger
authors.forename: S D
authors.initials: SD
authors.lastname: Davis
mesh_terms: D001272:Atmosphere; D002245:Carbon Dioxide; D004367:Dry Ice; D005118:Extraterrestrial Environment; D018535:Mars; D014867:Water
chemical_list: D004367:Dry Ice; D014867:Water; D002245:Carbon Dioxide