Greenland’s melting glaciers spew a complicated treasure: sand

The resource happens to be extremely good for making concrete. While Greenland's glaciers melt, super-valuable sand is spewing from them at a rate that's actually growing an island. It's left the nation with an economic and social dilemma: is exploiting that valuable, abundant resource on a wider scale environmentally, socially, and economically justifiable? Matt Simon investigates.