Two Antarctic weather stations recorded unprecedentedly high temperatures in March—offering grim evidence of accelerating climate change.
A potential Antarctica record high of 63.5 degrees Fahrenheit was recorded on March 24 at the Esperanza Base, just south of the southern tip of Argentina—a temperature exceeding any figure yet observed on the Antarctic landmass or Peninsula, according to the Weather Underground blog. The previous record high at the base, of 62.7 degrees Fahrenheit, was recorded in 1961.
The Esperanza reading came one day after a nearby weather station, at Marambio Base, saw a record high of its own: 63.3 degrees Fahrenheit.
"One surprising aspect of the temperatures measured recently at Esperanza and Marambio are that they occurred in autumn, nearly three months past the usual warmest time of the year in the Antarctic Peninsula," notes Weather Underground.
The Guardian further explains:
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[W]hether 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 separate study published in the journal Science at the end of March found that some ice shelves in the western part of the continent have lost up to 18 percent of their thickness in less than two decades.
The floating ice shelves surrounding the Antarctic Ice Sheet act as a "buttress to the 'grounded' ice, helping slow the flow of the ice sheet's glaciers into the ocean," Science journalist Carolyn Gramling explained.
She continued: "But warming ocean waters have been eating away at the underside of these ice shelves, thinning them in many places and reducing their ability to buttress the ice. This effect is particularly apparent in parts of the West Antarctic Ice Sheet (WAIS), long regarded as the more vulnerable part of the continent to climate change. Two regions of the WAIS, the Amundsen and Bellingshausen seas, have experienced especially dramatic losses of ice over the last couple of decades."