Mark McClusky says for elite athletes today, pushing boundaries and breaking records is all about "the aggregation of marginal gains."
A sheet of ice, twice the size of Manhattan, broke of from a glacier in Greenland this week.
The new iceberg measures 46 square miles. In 2010, the Petermann Glacier lost chunk of ice measuring 96 square miles. The loss of glacier mass in Greenland, which has seen warming temperatures, has scientists concerned.