)Greenland's ice sheet contains enough water to increase global sea levels by 7 meters. In any case, if it were to melt completely, it would take many centuries. Recent melting of the Greenland ice sheet is estimated to have contributed up to 0.7 millimeters a year to sea level rise (about one quarter of the total global average sea level rise of about 3.1 mm/year). Projections for global average sea level rise estimates by 2100 vary from 0.2 to 2.0, depending on the model and scenario used.