And now the last holdout has succumbed: Antarctica had been the only one of the seven continents that measurements showed was not heating up, but a new analysis of the past 50 years, using more complete records than ever before, shows that the mercury has been rising on the southern continent, too.
Until now, scientists had recorded strong warming of the Antarctic Peninsula but slight cooling of the interior since the 1950s. The supposed cooling has delighted climate contrarians, such as the prolific Senate staffer (to “global warming is the biggest hoax” Sen. James Inhofe) Marc Morano, who has written, "Contrary to media hype, the vast majority of Antarctica has cooled over the past 50 years."
Unfortunately for anyone who still harbors hopes that the laws of atmospheric physics have been repealed, that is not the case. Previous temperature recordings have been skewed by the sparseness of weather stations in Antarctica (all but two are on the coasts rather than the continental interior) and the short duration of the observations. The most complete analysis to date, using weather-station data supplemented by satellite records and statistical models, is being reported this afternoon in Nature. It finds that “significant warming extends well beyond the Antarctic Peninsula to cover most of West Antarctica, an area of warming much larger than previously reported,” scientists led by Eric Steig of the University of Washington and Drew Shindell of NASA’s Goddard Space Flight Center.
The west Antarctic warmed 0.17 degree C. per decade since 1957—that is, 0.85 degree C. in 50 years—mostly in winter and spring. Although East Antarctica cools in the autumn compared to past decades, they find, “the continent-wide average near-surface temperature trend is positive,” warming about 0.12 degree C. per decade.
I look forward to the climate contrarians' arguments that this observed warming is a natural occurrence and has nothing to do with manmade greenhouse gases.