Ice floating in the ocean off Antarctica has shrunk dramatically since 2014, a new study reveals.
However, the same paper has scientists puzzled about the nature of sea ice in the region.
Forty years of satellite data on sea ice has been studied extensively by researchers, showing that Antarctic sea ice was growing unexpectedly for decades before the sudden decline.
Scientists are at a loss for an explanation.
Satellite findings: record high and lows
The study, published this week in the journal Proceedings of the National Academy of Sciences, was drawn from the Nimbus 7 meteorological satellite, launched by NASA in 1978.
The findings are so striking because they show record high sea ice coverage in 2014 and record lows in 2017.
“It was just three years later [after the record high] that we had a record low, which is quite a rapid shift,” Parkinson told NBC News.
“The magnitude of that decrease from 2014 to 2017 was more than the decrease that has happened in the Arctic over more than 30 years.”
What caused the shift?
While there are hypotheses, there is no consensus amongst scientists.
One theory suggests that the record highs might be accounted for by the recovery of the ozone layer above Antarctica, over the same period.
Other scientists say the shift in sea ice might simply represent a natural shift in climate patterns.
It is also too soon to attribute the shifting ice levels to climate change:
“To argue that this recent dip is evidence of the start of a longer-term decline driven by greenhouse warming is premature,” Mark Serreze, director of the US National Snow and Ice Data Center told New Scientist.
The main point that scientists do agree on is that more research is needed to understand the shift in sea ice levels.
“We’ve now got 40 years of data, so we can look more holistically at the interactions between the tropics and the polar regions, the ice and atmosphere,” Julie Arblaster, an atmospheric scientist at Monash University in Melbourne, but not involved with the new study, told NBC News.