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Dec. 6, 2001

Donald Savage
Headquarters, Washington
Phone: 202/358-1727

Mary Hardin
Jet Propulsion Laboratory, Pasadena, Calif.
Phone: 818/354-0344

Tim Tawney
Goddard Space Flight Center, Greenbelt, Md.
Phone: 301/614-6573

RELEASE: 01-240

NASA’s Global Surveyor Sees Possible Climate Change on Mars

The planet Mars we know today is a cold, dry, desert world, but suppose the Martian climate is changing even now, year to year and decade to decade?

New observations by NASA's Mars Global Surveyor spacecraft are expanding understanding of the Martian climate and may indicate the climate is changing significantly even today. This suggests even larger climate changes have occurred during the planet's recent history and may again in its future. The observations were made during a full Martian year, 687 Earth days.

Compare each image on the left with their counterparts on the right. Small hills vanished and pit walls
expanded between 1999 and 2001.The pits are formed in frozen carbon dioxide, and the carbon dioxide
is subliming away a little more each Martian year. Sunlight illuminates each of the four different scenes
from the upper left.
CLICK HERE for animation of one of these 4 panels (1.6 MBytes).
CLICK HERE for animation of all 4 of these panels (6.2 MBytes).

If this is so, Mars might someday become warmer and wetter, as some scientists suggest it was during its early history. Papers detailing these observations are published in the Dec. 7, 2001, issue of Science magazine.

"If the environment of Mars has really changed by as much and over as short a time-scale as our observation implies, there should be attributes of Mars reflecting these changes that may be measurable by landers," said Dr. Michael Malin, principal investigator for Global Surveyor's camera system at Malin Space Science Systems, San Diego. "If Mars had a higher atmospheric pressure in the not-too-distant past, it is more likely that water was present as a liquid near the surface."

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Dan