New study documents the natural relationship between CO2 concentrations and sea level

http://www.eurekalert.org/pub_releases/2013-01/nocs-nsd010213.php

Public release date: 2-Jan-2013
Contact: Catherine Beswick
National Oceanography Centre, Southampton (UK)

By comparing reconstructions of atmospheric CO2 concentrations and sea level over the past 40 million years, researchers based at the National Oceanography Centre, Southampton have found that greenhouse gas concentrations similar to the present (almost 400 parts per million) were systematically associated with sea levels at least nine metres [more than 29 feet] above current levels.

The study determined the 'natural equilibrium' sea level for CO2 concentrations ranging between ice-age values of 180 parts per million and ice-free values of more than 1,000 parts per million.

It takes many centuries for such an equilibrium to be reached, therefore whilst the study does not predict any sea level value for the coming century, it does illustrate what sea level might be expected if climate were stabilized at a certain CO2 level for several centuries.