East Antarctic Ice Sheet

80°S 60°E / 80°S 60°E / -80; 60

The East Antarctic Ice Sheet (EAIS) is the sector of the Antarctic Ice Sheet covering East Antarctica. The ice sheet first formed around 34 million years ago, and, considered independently, is the largest ice sheet on Earth, with greater volume than the Greenland Ice Sheet or the West Antarctic Ice Sheet (WAIS). It is around 2.2 km (1.4 mi) thick on average and is 4,897 m (16,066 ft) at its thickest point. , from which it is separated by the Transantarctic Mountains. The EAIS is home to the geographic South Pole, magnetic south pole and the Amundsen–Scott South Pole Station.

The surface of the EAIS is the driest, windiest, and coldest place on Earth. Lack of moisture in the air, high albedo from the snow as well as the surface's consistently high elevation results in the reported cold temperature records of nearly −100 °C (−148 °F). It is the only place on Earth cold enough for atmospheric temperature inversion to occur consistently. That is, while the atmosphere is typically warmest near the surface and becomes cooler at greater elevation, atmosphere during the Antarctic winter is cooler at the surface than in its middle layers. Consequently, greenhouse gases actually trap heat in the middle atmosphere and reduce its flow towards the surface while the temperature inversion lasts.

East Antarctica has experienced slight cooling for decades while the rest of the world has warmed as the result of climate change. Clear warming over East Antarctica started has occurred at least since the year 2000 but was not conclusively detected until the 2020s. In the early 2000s, cooling over East Antarctica seemingly outweighed warming over the rest of the continent. It was frequently misinterpreted by the media and occasionally used as an argument for climate change denial.

After 2009, improvements in Antarctica's instrumental temperature record proved consistent warming over West Antarctica. Net warming has occurred across the continent since 1957. Because the East Antarctic ice sheet has warmed unevenly, it is still gaining ice on average. GRACE satellite data indicated East Antarctica mass gain of 60 ± 13 billion tons per year between 2002 and 2010. It will most likely see sustained losses of ice at its most vulnerable locations such as Totten Glacier and Wilkes Basin.