Sea ice melt hurts fragile wildlife

Antarctica has lost a record 1 million square kilometres of ice – an area nearly four times the size of New Zealand – in the Weddell Sea in the past five years, according to new research.

The loss of one-third of the region’s sea ice was keenly felt by the penguins and seals relying on the habitat for food, breeding and raising their young.

An international research team brought together satellite records of the sea ice and weather reports from 1978 to 2019 in a paper published in the journal Geophysical Research Letters.

They found the sea ice around Antarctica had been steadily increasing until 2016, when a series of events hit the continent.

In September 2016, unusually strong westerly winds whipped across the northern Weddell Sea.

These winds both shifted sea ice out of the area and created a large open stretch of water (known as a ‘‘polynya’’) or gap within the ice. This kicked off the melting, coauthor and Victoria University postdoc research fellow Dr Kyle Clem said.

‘‘As we headed into spring the sun was getting stronger in Antarctica, so that open water – the polynya – was able to absorb the sun’s energy and that persisted through the rest of the year.’’

Then in December, a series of unusual storms developed, drawing warm air towards the South Pole and supercharging the melt.

‘‘That brought in really, really warm northerly flow into an area that had already lost a bunch of sea ice,’’ Clem said. ‘‘That helped to keep melting the sea ice.’’

Co-author Dr Eugene Murphy, of the British Antarctic Survey, said the decline had significantly affected the marine ecosystem, from tiny algae up to whales.