(WASHINGTON) — The amount of ice circling Antarctica is suddenly plunging from a record high to record lows, baffling scientists.

Floating ice off the southern continent steadily increased from 1979 and hit a record high in 2014. But three years later, the annual average extent of Antarctic sea ice hit its lowest mark, wiping out three-and-a-half decades of gains — and then some, a NASA study of satellite data shows.

In recent years, “things have been crazy,” said Mark Serreze, director of the National Snow and Ice Data Center. In an email, he called the plummeting ice levels “a white-knuckle ride.”

Serreze and other outside experts said they don’t know if this is a natural blip that will go away or more long-term global warming that is finally catching up with the South Pole. Antarctica hasn’t showed as much consistent warming as its northern Arctic cousin.

“But the fact that a change this big can happen in such a short time should be viewed as an indication that the Earth has the..