The groundbreaking new research was conducted by an international team of researchers from the Niels Bohr Institute at the University of Copenhagen, England and Finland.
According to the UN's IPCC, the global climate in the coming century will be 2-4 degrees warmer than today, but the ocean is much slower to warm up than the air and the large ice sheets on Greenland and Antarctica are also slower to melt.
The great uncertainty in the calculation of the future rise in the sea level lies in the uncertainty over how quickly the ice sheets on land will melt and flow out to sea.
The model predictions of the melting of the ice sheets are the basis for the IPCC's predictions for the rise in sea level are not capable of showing the rapid changes observed in recent years.
The new research has therefore taken a different approach.
"Instead of making calculations based on what one believes will happen with the melting of the ice sheets, we have made calculations based on what has actually happened in the past," said Aslak Grinsted, who is a geophysicist at the Centre for Ice and Climate at the Niels Bohr Institute at the University of Copenhagen. "We have looked at the direct relationship between the global temperature and the sea level 2000 years into the past," he explained.
With the help of annual growth rings of trees and analysis from ice core borings, researchers have been able to calculate the temperature for the global climate 2000 years back in time.
For around 300 years, the sea level has been closely observed in several places around the world and in addition to that there is historical knowledge of the sea level of the past in different places in the world.
By linking the two sets of information together, Aslak Grinsted could see the relationship between temperature and sea level.
Assuming that the climate in the coming century will be three degrees warmer, the new model predictions indicate that the ocean will rise between 0,9 and 1,3 meters.
To rise so much so quickly means that the ice sheets will melt much faster than previously believed.
According to Grinsted, in the current situation with global warming, the sea level will rise by a meter in the span of the next 100 years.&13;&13;