Greenland has a very large proportion of the world's accessible fresh water. Something America is rapidly running out of because water is being pumped out of the ground faster than it's being replenished. Couple that with all the minerals and ores being exposed due to the melting glaciers and Greenland is a pretty important strategic interest to the U.S.
Yeah I originally put penguins but decided to fact check myself. They do not have penguins, but do have polar bears, humback whales, reindeer, and walruses.
Greenland seems pretty cool as is. I see no reason why we need to mess it up.