why GREENLAND called so whereas it has no vegetation????

I have read something that it was actually a trick to attract the settlers to move to Greenland. The information and communications during the colonization time was not good enough, and a good name is sufficient to give the settlers an impression that the barren Greenland is a fertile and warm land.

According to Eirik the Red's saga, he discovered the island and called it "Greenland" because he thought that "men will desire much the more to go there if the land has a good name" http://www.gutenberg.org/files/17946/17946-h/17946-h.htm

When Greenland was discovered and settled by the Vikings, it was much warmer. It actually was green back then. Since those times the earth has gotten colder. Now, as the earth is starting to naturally warm back up, lot's of people are getting all excited. It is nothing to worry about, really. It is just the natural cycle of things.