Seesaw does not explain Antarctic climate change



The Arctic has warmed rapidly in the past 3 decades, but temperature records show that the Antarctic on average has warmed less. This observation hints at a bipolar seesaw mechanism, in which changes in ocean circulation result in changes in heat transport between the hemispheres, linking the warming Arctic to a lack of warming in the Antarctic. However, a new analysis by Schneider and Noone shows that this mechanism cannot explain Antarctic temperature variability or trends. The authors reviewed the data set used as the basis of the bipolar seesaw hypotheses and note that for the Antarctic region the data come from only one station prior to the mid-1940s and include only a few stations until the late 1950s. They estimated Antarctic climate variability using a variety of independent data, including the long station time series, a reconstruction of the Southern Annular Mode index (a measure of Southern Hemisphere atmospheric circulation variability), and an ice core–based temperature reconstruction.