Sea levels could rise significantly faster than previously thought, according to research conducted by the Australian National University, who’s researchers have used fossil corals to understand how warmer temperatures have impacted on polar ice sheets.


Dr Andrea Dutton, formerly of the Research School of Earth Sciences (RSES) at the ANU’s College of Physical and Mathematical Sciences and Professor Kurt Lambeck of the RSES, built a significant database by compiling age and evaluation data of fossil corals that live near the sea surface, and used a model to factor in the physics of how changing masses of ice sheets would affect regional sea level at the various fossil coral sites.


“In this way, we were able to account for the geographic variability in sea level observations from this time period and compute the highest point that average global sea level attained. The observations from the corals confirmed the sea level patterns that we predicted using the geophysical model,” Dr Dutton said.


“Sea level change – in the past, present, and future – is geographically variable and we must consider this variability to infer what the average global sea level was doing in the past. We observed 5.5 to 9 metres of sea level rise. To explain that, polar ice sheets must have melted: part of Greenland, most of the West Antarctic ice sheet, and perhaps some of the East Antarctic ice sheet. Our findings have important implications for future sea levels.”


“For the period we studied, the poles were probably only 3 to 5 degrees warmer than present.  That amount of polar warming is well within what we are predicted to reach this century. This implies that the polar ice sheets may be very sensitive to small increases in temperature.


“This magnitude of sea level rise – up to 9 metres – is obviously not going to happen overnight. But it could happen within a few centuries, so it is important to consider the long-term commitment we make in terms of total sea level rise when we talk about various targets and emission scenarios.