Antarctica Cooling Controversy

The Antarctica cooling controversy relates to questions posed in popular media regarding whether or not current temperature trends in Antarctica cast doubt on global warming. Observations unambiguously show the Antarctic Peninsula to be warming. Trends elsewhere on the continent show both warming and cooling but are smaller and dependent on season and the timespan over which the trend is computed; but more recent results from Steig et al. show warming over the entire continent. Climate models predict that temperature trends due to global warming will be much smaller in Antarctica than in the Arctic, mainly because heat uptake by the Southern Ocean acts to moderate the radiative forcing by greenhouse gases. The depletion of stratospheric ozone also has had a cooling effect, since ozone acts as a greenhouse gas.

There is no similar controversy within the scientific community, as the small observed changes in Antarctica are consistent with the small changes predicted by climate models, and because the overall trend since comprehensive observations began is now known to be one of warming. At the South Pole, where some of the strongest cooling trends were observed between the 1950s and 1990s, the mean trend is flat. Novelist Michael Crichton asserted that the Antarctic data contradict global warming. The few scientists who have commented on the supposed controversy state that there is no contradiction, while the author of the paper whose work inspired Crichton's remarks has said that Crichton "misused" his results.

In a more recent study released in 2009, historical weather station data was combined with satellite measurements to deduce past temperatures over large regions of the continent, and these temperatures indicate an overall warming trend. One of the paper's authors, Eric J. Steig of the University of Washington, stated "We now see warming is taking place on all seven of the earth’s continents in accord with what models predict as a response to greenhouse gases." A follow-up study by O'Donnell and others that strongly criticized the Steig et al. work nevertheless found significant warming in West Antarctica. O'Donnell et al. also confirmed that Antarctica overall has been warming since the 1950s, but disagreed with Steig et al. about the strength of that warming. However, subsequent measurements of temperatures in a borehole at the center of the West Antarctic ice sheet, by Orsi and others, found even larger positive trends than Steig et al.