The sea level rise following the industrial revolution has been speedy, and may reach above 80cm by 2100, and around 2.5 by the year 2200.
Researchers from the University of Southampton and the Australian National University used geological evidence of the past few million years to derive a background pattern of natural sea-level rise.
This was compared with historical tide-gauge and satellite observations of sea-level change for the 'global warming' period, since the industrial revolution.
Lead author Professor Eelco Rohling, from the Australian National University and formerly of the University of Southampton, said our natural background pattern from geological evidence should not be confused with a model-based prediction. It instead uses data to illustrate how fast sea level might change if only normal, natural processes were at work.
"There is no speculation about any new mechanisms that might develop due to man-made global warming. Put simply, we consider purely what nature has done before, and therefore could do again," Rohling said.
Rohling concluded saying that for the first time, they saw that the modern sea-level rise is quite fast by natural standards. Based on our natural background pattern, only about half the observed sea-level rise would be expected.
The study is published in journal Scientific Reports.