Observational Evidence for an Active Surface Reservoir of Solid Carbon Dioxide on Mars
Michael C. Malin,*
Michael A. Caplinger,
Scott D. Davis
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.
Malin Space Science Systems, Post Office Box 910148, San Diego, CA
92191-0148, USA.
*
To whom correspondence should be addressed.