McMurdo and the Ross Ice Sheet are in and part of the "West Antarctic Ice Sheet" (WAIS). The WAIS has the ability to raise world wide sea levels almost over night by about 20 feet. The reason for this is the WAIS is is a ice sheet that is grounded BELOW sea level i.e. it is NOT floating on water like an ice shelf, but is directly atop ground that is below sea level (they may be some water/slush underneath the ice Sheet to act as a lubricate but the ice exceeds the water the ice would be if it is melted, in ice shelves, the ice floats on top of water, so when it melts there is NOT net increase in water levels, thus ice sheets are more dangerous then ice shelves).
Now, every March, the Antarctic is at is lowest amount of ice, thus if you are going to see a rapid deterioration of the WAIS it will be in March or about early April (By the middle of April temperatures in Antarctic during the Southern Hemisphere' autumn, starts an expansion of Antarctic Ice, so the problem then waits anther year.
The various islands among the Ross Ice Sheet is believed to hold the Ice Sheet together, thus the importance of the phase "Ross Ice Shelf is separating quickly from Ross Island". Now that is the Ice Shelf not the Ross Ice Sheet, but the shelf is believe to protect the ice sheet from the full affect of the increase in Global temperatures. If to much of the Ice Shelves go, the ice sheet will follow and IF that happens world wide water levels raise 20 feet.
Hopefully this is NOT the trigger to set free the whole Ice Sheet, but many scientists believe it has happened before. See the "Madhouse Century" for more details.
http://www.imaja.com/as/environment/can/journal/madhousecentury.htmlhttp://findarticles.com/p/articles/mi_hb6393/is_n3_v13/ai_n28708530/http://climatechangepsychology.blogspot.com/2010/02/is-madhouse-century-knocking-at-our.htmlI do not want to sound like the boy who called wolf, and thus will NOT predict it will occur this year, but I have known about the possibility for many years and have mentioned it before on DU:
http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=115&topic_id=41468&mesg_id=41745