Essay by Eric Worrall
In 2014 NOAA blamed record high sea ice on global warming. Now NSIDC blames record low sea ice on global warming.
World’s sea-ice falls to record low
Mark Poynting and Erwan Rivault
BBC Climate & Verify data journalism teams
The world’s frozen oceans, which help to keep the planet cool, currently have less ice than ever previously recorded, satellite data shows.
Sea-ice around the north and south poles acts like a giant mirror by reflecting much of the Sun’s energy back into space.
But as rising temperatures cause this bright layer to shrink, the dark ocean below can absorb more heat, warming the planet further.
This latest sea-ice low appears to have been driven by a combination of warm air, warm seas and winds breaking apart the ice.
…
“Every year, every data point that we get suggests that this isn’t a temporary shift, but something more permanent, like what we’ve seen in the Arctic,” Walter Meier, senior research scientist at NSIDC, told BBC News.
“It is indicating that the Antarctic has moved into a new regime of lower ice extents.“
…
Read more: https://www.bbc.com/news/articles/cvgeydkz08go
Back in 2014, melting glaciers making sea water less saline was blamed for record HIGH Antarctic sea ice.
Antarctic winter sea ice extent sets new record in 2014
BY MICHON SCOTT REVIEWED BY TED SCAMBOS
PUBLISHED OCTOBER 7, 2014DETAILS
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It’s not unreasonable to wonder how, if the planet is warming, Antarctic winter sea ice can set record highs. As the NSIDC release explains, Antarctica’s sea ice growth spurt may be down to stronger winds and slightly fresher sea surface water around the margins of the continent’s melting ice shelves.
…
Winds probably did not act alone to spur so much sea ice growth; melting land ice may have played a role. Most of Antarctica’s ice lies in the ice sheets that cover the continent, and in recent decades, that ice has been melting. Along the coastline, ice shelves float on the ocean surface, and much of the recent melt may be driven by warm water from the deep ocean rising and making contact with ice shelf undersides.
How does the melting of land ice matter to sea ice formation? The resulting meltwater is fresher than the seawater. As it mixes with the seawater, the meltwater makes the nearby seawater slightly less dense, and slightly closer to the freezing point than the ocean water below. This less dense seawater spreads out across the ocean surface surrounding the continent, forming a stable pool of surface water that is close to the freezing point, and close to the ice onto which it could freeze.
So as counterintuitive as expanding winter Antarctic sea ice may appear on a warming planet, it may actually be a manifestation of recent warming. “Both the Arctic and the Antarctic are responding to climate change, and both have areas that are warming rapidly,” explains NSIDC lead scientist Ted Scambos. “But Antarctic sea ice is responding to wind shifts and ocean changes in an unexpected way, and we’re still trying to fully understand it.”
References:
2014 melt season in review
Melting in the North, freezing in the South
Read more: https://www.climate.gov/news-features/featured-images/antarctic-winter-sea-ice-extent-sets-new-record-2014
Sea Ice scientists should come clean and admit they have no idea which direction sea ice will move next, instead of placing an each way bet, and blaming any change on global warming.
There is plenty of evidence Antarctic sea ice has varied wildly for at least the last century.
In 2013, the “Spirit of Mawson” Ship of Fools expedition got stuck in sea ice, while trying to relive a small part of Mawson’s Antarctic adventures.
The Antarctic sea ice got so bad there was talk of relocating the Mawson base.
What was Antarctic sea ice like in Mawson’s day? While a lot of bad things happened during the Mawson expeditions, in 1911 and 1929, and his other visits to Antarctic, Mawson managed to reach Antarctica on at least three occasions, unlike the Ship of Fools.
Arctic sea ice has also proven highly variable over the years, with long periods of sustained melt and freeze, many of which occurred well before anthropogenic CO2 could have become a significant factor.
What can we conclude from all this?
It seems pretty obvious that declaring a “new regime” of lower sea ice extent on the strength of a decade of sea ice retreat is premature, given the history of extreme natural variability. In addition, the confused global warming “explanation” for the 2014 record extent of Antarctic Sea Ice in my opinion suggests present day claims that global warming is now driving sea ice decline are just speculation.
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