Much of this around Greenland has to do with the ongoing land and sea blockade of Kaliningrad. It hasn't been widely reported in the Western media, but it could be the next major flashpoint between Russia and the E.U. Similar to Crimea, Russia wants it's access to the Baltic Sea restored and Kaliningrad is a key part of this.
Standing between the English Channel, North Atlantic and Kaliningrad are three waterways through Danish territory. Now because Putins friend in the U.S. is threatening to invade a Danish controlled island (that the U.S. already has a military base on, and effectively controls militarily already), Denmark now has to split its forces to a degree, making it much easier for Russia to accomplish its goals in the Baltic Sea.
2 hours agoby treebeard901