A top United Nations official on climate change said on Tuesday that record high temperatures in Antarctica were evidence that even "the most remote and pristine places on our planet are being impacted by climate change".

Petteri Taalas, secretary-general of the World Meteorological Organization (WMO), said that while research bases on Antarctica had previously recorded temperatures topping the freezing mark of 0°C, "this is the first time we have seen temperatures over the 20°C threshold".

He said the latest high temperature was part of "a long-term warming trend on the peninsula" and comes after 2020 was the second-warmest year on record for the Antarctic Peninsula.

"The Antarctic ice sheet contains enough ice to raise sea levels by over 60 metres, so melting of ice there could have a devastating impact for future generations and is a major focus for WMO science," Taalas said in a statement.

"WMO's 62nd Executive Council, meeting virtually, is expected to confirm these temperature observations later today," he added.

Climate scientist Walt Meier, a senior research scientist at the National Snow and Ice Data Center in the United States, said the event should "really sound an alarm bell".

"The impacts of human activity on Antarctica and the Southern Ocean are clear and cannot be ignored," he told the AFP news agency.

Meier said that while parts of Antarctica were experiencing more melting than usual "at various times of the year for various regions", the current high temperatures were "more unusual" and "a significant event".

According to the WMO, the previous highest temperature recorded on the continent was 18.3°C in 2015 at an Argentine research base on the Antarctic Peninsula.

The Antarctic Peninsula, together with the Arctic region, is among the fastest-warming areas of the world, with temperatures rising at about three times the global average.

Scientists have warned that this rapid warming is having a major impact on the Antarctic ice sheet, which is melting at an increasing rate and contributing to rising sea levels.

The WMO's statement comes as world leaders prepare to meet in Glasgow, Scotland, for the 26th UN Climate Change Conference of the Parties (COP26) in November.

The conference is seen as a critical opportunity for countries to agree on more ambitious emissions reduction targets to limit global warming to 1.5°C, the level scientists say is necessary to avoid the worst effects of climate change.