On December 13, 2006, scientists warned that the Arctic ice is melting at a rate faster than was estimated. The ice has been shrinking steadily over the past 30 years, but now scientists say there's a possibility of an ice-free Arctic in the next few decades. Bruno Tremblay, assistant professor with McGill University in Montreal, says this melting ice sheet will considerably increase the sea level. The US Geological Survey has estimated that if all the ice sheets melt the total volume added to the sea will be roughly 32.33 million cubic kilometres (USGS 002-00, January 2000). Vanishing ice sheets are not the only factor leading to a rise in sea level. As temperatures rise, the sea will absorb heat from the atmosphere and expand. The sea level will rise further.

It has risen more than 120 metres since the peak of the last ice age about 18,000 years. The bulk of that occurred before 6,000 years ago. From 3,000 years ago to the start of the 19th century, sea level was almost constant, rising at 0.1 to 0.2 mm/yr. Since 1992, a rise of about 3 mm/yr has been observed. This change may be the first sign of the effect of global warming on sea level. Global warming, it is predicted, will cause significant rises in sea level in the 21st century. According to the Intergovernmental Panel on Climate Change, by 2080, sea levels could rise from 9 cm to 48 cm in a