"Lessons from the Earth's History"

The figure below shows sea levels of past and present as function of the averaged global surface temperature. During most of the Eocene the greenhouse gas concentrations ('parts per million') in the atmosphere and the corresponding temperatures were so high that even Antarctica was ice free and sea levels - corrected for present average ocean depth of about 3700 m - were about 65 to 70 m higher than today. The light blue curve connects the Eocene point via the Mid-Pliocene Warm Period, the Eemian, the Holsteinian and Today (A.D. 2014) with the one of the last ice age - Last Glacial Maximum - when sea levels were some 200 m lower for a total temperature drop of only 12° Celsius.

PawPlot - P.Duinker

Source: "Climate sensitivity, sea level and atmospheric carbon dioxide, Hansen et al., 2013 . The text inside the graph and the title itself is clickable and leads to additional information. For sea level measurements since 1880 click here and for the video presentation by J. Mitrovica "The Fingerprints of Sea Level Change" click here.

  The figure does not gives us an answer to the obvious question: "How long will it take before large parts of the icesheets of Greenland and Western-Antarctica are melted as a consequence of the rising CO₂ levels in the atmosphere causing an expected temperature rise in this century of (3±1)° Celsius?" and " Will the sea rise together with the temperature or is there a delay of hundreds or even thousands of years?" Related to this question a special report titled 'The Future of the Oceans' to the German government in 2006 makes the following remarks on the melting of the ice after the Last Glacial Maximum:

From 15,000 to 10,000 years ago sea level rose by around 80m, an average of 1.6 m per century (Fairbanks, 1989). During some intervals rates of up to 5 m per century were reached (Clark et al., 2004).
These values cannot simply be applied to today’s situation. The ice sheets at that time were considerably larger, which means the melting regions on the margins were greater, allowing a greater flow of meltwater. In addition, due to Earth’s orbital cycles around the sun (Milankovich cycles; Ruddiman, 2000), the incoming solar radiation at high latitudes of the Northern Hemisphere was considerably stronger, a situation that cannot be directly compared with the global increase in greenhouse gas concentrations. These two factors suggest higher melting rates at the end of the ice age than during the present warming. The much slower warming at that time, by contrast, would suggest lower melting rates. In fact, the disappearance of ice sheets at that time for the most part kept pace with the gradual climate warming, so the assumption that ice masses would have melted significantly more rapidly with faster warming is quite plausible.

See for the references the WBGU publication. On the next webpage the predictions of the sea levels for 2100 and 2300 are presented.