How much are glaciers and ice sheets contributing to global sea-level rise?

From measurements made by the IPCC it is clear that Global sea level is rising, however the direct cause of this rise is not yet fully certain, although there is strong evidence that glacier melt is a strong causal factor. Global sea level rose by about 120 meters during the several millennia that followed the end of the last ice age (approximately 21,000 years ago), and stabilized between 3,000 and 2,000 years ago. Global sea level did not then change significantly until the late 19th century when the record of sea level change shows evidence for an onset of sea level rise. Estimates for the 20th century show that global average sea level rose at a rate of about 1.7 millimetres per year. Satellite altimetry observations provide more accurate sea level data with nearly global coverage and indicate that since 1993 sea level has been rising at a rate of about 3 millimetres per year. Climate models based on the current rate of increase in greenhouse gases, however, indicate that sea level may rise dramatically more than this, at about 4 millimetres per year by the period 2090-2099 (IPCC).