Sensitivity of ice-cemented Antarctic slopes to increases in summer thaw

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 increase 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 remained physically stable for millions of years, then our results suggest that MSSST in the upland zone did not increase by more than ~5o to 9oC since deposition of most deposits, perhaps as much as 10 million years ago.