""This combination of factors, all these things coming together in a single year, was basically the 'perfect storm,' for Antarctic sea ice," said corresponding author Malte Stuecker, a UW postdoctoral researcher in atmospheric sciences. "While we expect a slow decline in the future from global warming, we don't expect such a rapid decline in a single year to happen very often."
The area of sea ice around Antarctica at its peak in late 2016 was 2 million square kilometers (about 800,000 square miles) less than the average from the satellite record. Statistically, this is three standard deviations away from the average—an event that would be expected to occur randomly just once every 300 years.
The record low was not predicted by climate scientists, so UW researchers looked at the bigger picture in ocean and atmospheric data to explain why it happened.
The previous year, 2015-16, had a very strong El Niño in the tropical Pacific Ocean. Nicknamed the "Godzilla El Nino," the event was similar to other monster El Niños in 1982-83 and 1997-98. Unlike the 1997-98 event, however, it was only followed by a relatively weak La Niña in 2016.
Far away from the tropics, the tropical El Niño pattern creates a series of high- and low-pressure zones that cause unusually warm ocean temperatures in Antarctica's eastern Ross, Amundsen and Bellingshausen seas. But in 2016, when no strong La Niña materialized, researchers found that these unusually warm surface pools lingered longer than usual and affected freeze-up of seawater the following season.
"The study was published Aug. 24 in Geophysical Research Letters."
https://phys.org/news/2017-08-record-low-antarctic-sea-ice-due.html#jCpSo how much was due to climate change? What to believe a peer-reviewed paper or an opinion piece?