"The biggest concern is that the South Pole and Antarctic plateau doesn't rise above freezing as of now, but if you track the patterns closer to the coast that's when you see melting". Average temperatures there range from -60C (-76F) during winter to just -20C (-4F) during summer.
Antarctica's temperature varies widely according to season and region, and for years it had been thought that the South Pole had stayed cool even as the continent heated up.
The research was carried out by an worldwide team of scientists who examined weather station data, gridded observations and climate models to assess the impact of global warming at the South Pole. Over the past 30 years, warming in the western tropical Pacific Ocean - a region near the equator north of Australia and Papua New Guinea - meant there was an increase in warm air being carried to the South Pole.
The South Pole has been warming at more than three times the global average over the past 30 years, a new study has found.
Authors of the research said the natural warming trend was likely boosted by manmade greenhouse gas emissions and could be masking the heating effect of carbon pollution over the South Pole.
Dr Kyle Clem, a researcher at Victoria University of Wellington, and lead study author, said: "While temperatures were known to be warming across West Antarctica and the Antarctic Peninsula during the 20th century, the South Pole was cooling". Antarctica's interior has been found to have faced the most drastic climate shifts over the last 30 years and scientists think these abrupt changes are going to continue. The two factors "have worked in tandem to make this one of the strongest warming trends on Earth", the study warns.
The study was recently published in Nature Climate Change journal.
A "negative" state, conversely, is where the temperature anomaly is reversed.
The IPO flipped to a negative cycle at the start of the century.
The researchers say the actual observed warming exceeds 99.9 percent of all possible scenarios free of human influence, so while it is possible it could have occurred naturally, it is "extremely unlikely".