Greenland Ice Melt Could Raise Global Sea Levels Even Higher
04.09.2008 - Other
Researchers from around the world are still debating about how much and how quickly the Greenland ice sheet will contribute to global sea level rise in the future. Based on the closest ice sheet melt example having occurred in the past, scientists see that sea level rise could actually occur extremely rapidly.
In order to find clues concerning the rate of ice sheet melting, scientists from the University of Wisconsin and Columbia University's Center for Climate Systems Research studied the Laurentide Ice Sheet, which used to cover the Northern Hemisphere and which disappeared completely 6,500 years ago. Their results were published in Nature Geoscience.
The current rate of sea level rise is around 3mm/year. However, in its Fourth Assessment Report, the IPCC concluded that the rate of sea level rise could increase up to 59 cm a year by 2100. End-of -the-century estimations could even be so much as 20 cm higher than this if the Greenland and Antarctic ice sheets' melt rates were to increase in direct correlation with the rise in global average temperature.
There are two reasons making it difficult to determine the melting rate of ice sheets today:
- available data was collected over a very short period of geologic time
- ice sheet modelling is still in its infancy
Using terrestrial and marine records to reconstruct the rapid melting of the Laurentide Ice Sheet, scientists found that the main factor causing ice sheet melt was the increased solar radiation, and thus also summer temperatures, which resulted from a change in the Earth's orbit. Their work suggests that future sea level rise rates of one metre per century are not completely out of the question.
