It's basic physics. I even had the question on what happens to the level of water when ice melts in a very elementary physics class I took in college. It stays the same. It doesn't matter if it's ice in a glass or ice in the ocean--when it melts, the water level remains the same, because it displaces the water it once sat in.
It is utter vanity assigning blame to human activity in accounting for fluctuations in natural patterns of the earth's (and other planets) weather. The earth has cycled into and out of several ice ages, all on its own, without the contribution of any human activity. The same holds true for other planets. A 100 million years ago, oceans covered much of what we know as land and continents today.
http://www.clearlight.com/~mhieb/WVF...ontinents.html The oceans receded all on their own, just as they once rose all on their own. The continents drifted and formed all on their own. Nothing man did or could do could or would alter or change this. The earth has always done what the earth does, and it always will, with or without humans inhabiting it.
PS
Parts of Greenland were once farmed.