Recent Water Activity on the Surface of Mars

There are two known reservoirs of water on Mars: the atmosphere, and the north polar cap. The latter contains possibly as much as 10 meters of water (global ocean equivalent). What happens to this water at high obliquity? Mars' obliquity varies chaotically on time scales greater than 10 million years and may have been as high as 60 degrees. We use a general circulation model with a simple hydrological cycle to address this question. We find that large ice sheets can build up in non polar regions at high obliquity. These results may help explain the puzzling observations of putative lakes, glaciers, and other ice-related features that seem to have existed in the relatively recent geological past.