Melting of Thwaites Glacier could rewrite global coastline

A warming atmosphere is creating concern in the Arctic Circle and on the continent of Antarctica. The Arctic Report Card shows high temperatures, shrinking sea ice and extreme melting events are transforming the region. At the opposite pole, in Antarctica, a key ice shelf that sits in front of the Thwaites Glacier could break up much sooner than expected — within 5 years. William Brangham reports.