Antarctic sea ice loss

Antarctic had defied climate change with increasing ice extents since recording began in the 1970s, but over the last five years there has been a reversal and a major loss of ice.

RNZ:  Antarctic lost sea ice twice the size of Spain in five years, researchers say

Part of the Antarctic has lost more than one million square kilometres of sea ice over the past five years, new research shows.

An international research team found that a series of severe storms in the Antarctic summer of 2016-2017 caused a reduction in a third of the sea ice in the Weddell Sea.

Ice loss also occurred due to the re-appearance of an area of open water in the middle of the ‘pack ice’ – otherwise called a polynya, the researchers say.

The opening of the ice created more visible ocean for the sun to warm up, causing further reductions, Clem said.

“We already have less sea ice now that the storms have redacted it out and melted it, we also saw open water emerge with the polynya, so the sun started heating the ocean and that has lead to a warmer ocean and less sea ice, which has persisted for the following four years.”

Data on the Weddell Sea only dates back to the 1970s when satellites allowed them to monitor weather patterns, he said.

Because there was only about 40 years of data to learn from, he said it was impossible to predict long term weather trends.

While these storms were unprecedented from the patterns over the past 40 years, it was unclear if that would be the case over a longer period of time, Clem said.

The study’s lead author, professor John Turner, who is a climate scientist at British Antarctic Survey, said the Antarctic continued to change and created problems for wildlife.

‘”Antarctic sea ice continues to surprise us. In contrast to the Arctic, sea ice around the Antarctic had been increasing in extent since the 1970s, but then rapidly decreased to record low levels, with the greatest decline in the Weddell Sea.

“In summer, this area now has a third less sea ice, which will have implications for ocean circulation and the marine wildlife of the region that depend on it for their survival.”

Turner said this rapid sea ice loss was not limited to the Weddell Sea ecosystem, but the wider Antarctic wildlife, plants and animals.

The ice loss is over too short a timeframe to know what the longer term implications are, but it adds to the knowledge of ice extents and climate change.