We employed a Mohr-Coulomb safety factor equation to assess the response of ice-cemented slopes in the stable upland zone of the McMurdo Dry Valleys (MDV) to artificial increases in mean summertime soil surface temperatures (MSSST). Results show that ice-rich, silty tills on slopes ≥20° could fail by planar sliding with an in-crease in MSSST of ~5º to 9ºC.  This change corresponds to an atmospheric increase of  ~5º to 9ºC, which lies just outside the envelope of warming predicted to occur in this region over the next century. If we assume that current soil-moisture conditions can be applied to slope deposits in the distant past, and that these slope deposits have re-mained physically stable for millions of years, then our results suggest that MSSST in the upland zone did not in-crease by more than ~5º to 9ºC since deposition of most deposits, perhaps as much as 10 million years ago.