The polar amplification asymmetry: role of Antarctic surface height

In the long run, a successive lowering of the altitude of the ice sheet makes Antarctica more prone to melting.

Marc Salzmann, study author from the University of Leipzig

• States that previous studies have attributed an overall weaker (or slower) polar amplification in Antarctica compared to the Arctic to a weaker Antarctic surface albedo feedback and also to more efficient ocean heat uptake in the Southern Ocean in combination with Antarctic ozone depletion
• Investigates the role of the Antarctic surface height for meridional heat transport and local radiative feedbacks, including the surface albedo feedback
• Finds that a considerable fraction (between 24 and 80 % for three consecutive 25-year time slices starting in year 51 and ending in year 126 after CO2 doubling) of the polar amplification asymmetry was explained by the difference in surface height, but the fraction was subject to transient changes and might to some extent also depend on model uncertainties
• Results suggest that warming in the Antarctic could speed up in the centuries to come as the ice sheets flatten out as they melt