Antarctica records unprecedented high temperatures in two new readings

The 20th anniversary of the discovery of the first “hole” in the ozone layer on Tuesday had many climate observers focused on the Arctic, where a study published last week found that polar bears were eating more birds’ eggs, perhaps due to lost hunting grounds with the disappearance of summer ice.

But equally significant climate news was playing out in Antarctica, where two climate stations registered ominous new potential measurements of accelerating climate change.

A weather station on the northern tip of the Antarctic peninsula recorded what may be the highest temperature ever on the continent, while a separate study published in the journal Science found that the losses of ice shelf volume in the western Antarctic had increased by 70% in the last decade.

Helen A Fricker of the Scripps Institution of Oceanography at the University of California, San Diego, a co-author of the Science report, said that there was not necessarily a correlation between recent temperature fluctuations and disappearing ice.

“While it is fair to say that we’re seeing the ice shelves responding to climate change, we don’t believe there is enough evidence to directly relate recent ice shelf losses specifically to changes in global temperature,” Fricker said in an interview with Reuters.

What was incontestable were the unprecedentedly high temperature readings on the Antarctic ice mass.

The potential Antarctica record high of 63.5F (17.5C) was recorded on 24 March at the Esperanza Base, just south of the southern tip of Argentina. The reading, first noted on the Weather Underground blog, came one day after a nearby weather station, at Marambio Base, saw a record high of its own, at 63.3F (17.4C).

By any measure, the Esperanza reading this week was unusual. The previous record high at the base, of 62.7F (17.1C), was recorded in 1961.

But whether the recent readings represent records for Antarctica depends on the judgment of the World Meteorological Organization, the keeper of official global records for extreme temperatures, rainfall and hailstorms, dry spells and wind gusts. The WMO has recorded extreme temperatures in Antarctica but not settled the question of all-time records for the continent, according to Christopher Burt of Weather Underground.

One complicating factor is debate about what constitutes “Antarctica”. Both Esperanza and Marambio lie outside the Antarctic circle, though they are attached to the mainland by the frozen archipelago that is the Antarctic peninsula.

A conservative definition of what Antarctica is would seem to award the distinction of hottest-ever temperature to a 59F (15C) reading nearer the South Pole from 1974, according to Burt.