I'm going to go with Greenland is a frozen rock and isn't green at all. I think that's how the naming went. And Iceland is much more green than Greenland.
greenland vvas named as such by the vikings so that enemies vvould go there thinking it vvas a nice place to invade/live and then they name iceland vvell , iceland to keep enemies avvay and have them think it vvas just a horrible icy place.