(CTN NEWS) – Since we started measuring it with satellites in the late 1970s, there is presently less sea ice surrounding the Antarctic continent than ever before.
According to the National Snow and Ice Data Center, this year is exceptional even though it is the summer in the southern hemisphere when you would expect less sea ice.
On February 13, coverage was only 1.91 million square kilometers (737,000 square miles) because to winds, warmer air, and water.
However, this summer’s melt still has a ways to go.
Last year, it took until 25 February to achieve the previous record-breaking minimum of 1.92 million sq km (741,000 sq miles).
In the past seven years, three years with record-low sea ice have occurred: 2017, 2022, and now 2023.
As they go around the continent, research, cruise, and fishing ships are all describing a similar scene: the majority of sectors are essentially ice-free.
The only area still dominated by frozen floes in the Weddell Sea.
What Makes This New Record So Unusual?
The behaviour of Antarctic sea ice is thought by scientists to be a complex process that cannot just be attributed to climate change.
The sea-ice extent exhibits significant variability when data from the last 40 or more years of available satellite data are included. Only in the last several years has there been a noticeable decline in the summer ice volume.
Similar to what we have observed in the Arctic, where the area of summer sea ice has been decreasing by 12–13% every decade as a result of global warming, computer models had indicated that it would exhibit long-term decline.
Yet that hasn’t been how the Antarctic has acted.
We can look back at least as far as 1900 using data from sources other than satellites.
They show that Antarctic sea ice was declining at the beginning of the last century before beginning to grow.
With record satellite winter maximums and now record satellite summer minimums, it has recently displayed significant fluctuation.
The floes can cover up to 18 million square kilometers (6.9 million square miles) throughout the winter.
How Much Ice Are 1 Million Square Kilometres?
In general, it is what the summer ice pack this year lacks compared to the longer-term average. The British Isles are covered by that.
It will soon begin to expand once more, and for a variety of reasons, it is crucial that it does.
Seawater that has frozen at the ocean’s surface loses salt, which makes the water below denser and causes it to sink.
This is a component of the water mass flow that powers the huge ocean conveyor, which helps control energy in the climate system.
The importance of sea ice to life at the poles cannot be overstated.
The little crustaceans known as krill, which are a staple food source for whales, seals, penguins, and other birds, are fed on the algae that adhere to the ice in the Antarctic.
Several species will haul out and rest on the sea ice as a platform.
Warm Air Increases Melt
The extremely hot air temperatures to the west and east of the Antarctic Peninsula most certainly contributed to this year’s record sea-ice minimum.
They have been 1.5C warmer than usual over the long run.
The Southern Annular Mode (SAM), a significant actor in the area, is another phenomenon that exists.
It discusses changes in the area’s atmospheric pressure, which has an impact on the continent’s well-known westerly winds that circle it.
The mode is reportedly currently in a significantly positive phase.
This intensifies the current westerly winds and pushes them poleward.
Flutes are broken up and pushed northward into warmer waters by increased storminess, where they melt out.
The presence of an ozone hole over Antarctica and the increase in greenhouse gases in the atmosphere, according to researchers, are likely causes of the more encouraging patterns in the SAM over a longer period of time.
In What Ways Does This Differ From Arctic Ice Melt?
It’s crucial to comprehend the variations between the poles.
Continents surround the Arctic Ocean, which is an ocean. Oceans encircle the continent of the Antarctic.
Ice growth in the Antarctic during the winter is substantially less limited due to geographic dispersion. As far north as the conditions will allow, the floes can form.
This explains why the extents are so much greater than in the Arctic, where maximums currently hardly ever exceed 15 million sq km (5.8 million sq miles).
The geology, however, also means that in many locations, summertime warmth can chase the sea ice all the way back to the Antarctic coastline.
Yet because the Antarctic struggles to maintain ice over the course of a year, its floes are often far thinner than those in the Arctic, measuring about one meter or less as opposed to three to four meters for long-lived ice in the polar north.
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