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"Climate scientists were hit hard by the sudden and extreme changes in Antarctica, likening it to a punch in the stomach."
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“Climate scientists were hit hard by the sudden and extreme changes in Antarctica, likening it to a punch in the stomach.”

Morning is a construct in the Antarctic summer. It’s 7.30am and Nerilie Abram, a climate science professor at the Australian National University, is having breakfast at Casey station when she takes Guardian Australia’s call in late November. The sun barely kissed the horizon the night before, and won’t fall below it for weeks.

The permanent sunlight in Antarctica can be disorienting for those new to the area, but for seasoned scientists like Abram, it is simply a part of daily life at the southernmost point of the planet. However, this year, there is something else that feels unusually peculiar.

Ten years ago, Abram witnessed a large chunk of ice floating near the shore. However, the view from her window has drastically changed since then. According to her, there is now no sea ice in sight, and the landscape is stunning. She also reflects on the impact of human activity and the changes happening in the environment, which she finds disheartening.

That punch has winded scientists and policymakers across the planet this year. As the hottest year on record crawls to its finish line, they have been asking: is 2023 the year humanity put its stamp on Antarctica in ways that will be felt for centuries to come?

The southern continent has suffered dramatic shifts that raise serious concerns about its immediate health. They have coincided with evidence that longer-term transformations linked to the climate crisis have started much sooner than it was assumed was likely.

The alterations have consequences for nearby animals, as well as for individuals worldwide in manners that are frequently not fully comprehended.

A list of worries

The extent of Antarctic sea ice dramatically declined for six consecutive months, reaching a level significantly lower than any other recorded by satellite. Scientists had difficulty finding words to accurately convey the magnitude of this event.

Although the complete impact has not been recorded, a study published in August provided some understanding of its potential implications. By analyzing satellite imagery, scientists from the British Antarctic Survey discovered that the previous record decrease in sea ice in late 2022 – prior to this year’s even larger decline – may have resulted in the deaths of thousands of emperor penguin chicks. The typically consistent sea ice that these colonies depend on for raising their offspring in the Bellingshausen Sea was absent, likely resulting in a “disastrous breeding setback”.

Emperor penguin and chick

The recent occurrence in the western region of the continent mirrored the extreme conditions in the eastern region – known as the coldest spot on the planet – from last year. This event, which scientists believe to be the most intense heatwave ever documented, saw temperatures reach a staggering 39C above average.

In a study recently published in Nature, it was discovered that the melting of ice sheets in Antarctica could significantly decrease the Southern Ocean’s overturning circulation by the year 2050 if greenhouse gas emissions remain unchanged. Another study by the same researchers estimated that this circulation, which impacts weather patterns, ocean temperatures, and nutrient levels globally, has already slowed by approximately 30% since the 1990s.

According to a separate study conducted by a different group of researchers, it has been proposed that the rapid melting of ice shelves in the Amundsen Sea in western Antarctica will continue uncontrollably for the remainder of this century, even if emissions are reduced significantly.

The pace of melting has significantly increased, three times more than the previous century. Previous research has shown that the entire west Antarctic ice sheet, which is safeguarded by ice shelves and could raise sea levels by five meters if completely melted, may eventually collapse.

Towards the end of the year, avian flu made its way to the sub-Antarctic area for the first occasion, raising worries about a possible ecological catastrophe if it were to extend to even more southern regions. It was stated that a gathering of 26 international governments focused on the Antarctic marine environment was unsuccessful in reaching a consensus on establishing new conservation zones, despite being presented with evidence showcasing the various crises at hand.

According to Matt King, the director of the Australian Centre for Excellence in Antarctic Science, the alterations in the ice and ocean have resulted in a sobering year for even the scientists involved.

Rarely have scientists been so taken aback by what they have observed in my career. They are truly concerned. It took them by surprise,” he states. “We were aware that significant changes were on the horizon, but we have witnessed processes that we believed would occur in the middle of the century happening much earlier.”

The decrease in floating ice was remarkably sudden. During the peak of winter, the frozen portion of the Southern Ocean was approximately 2.5 million square kilometers below the average of the past 40 years. This is equivalent to an area slightly larger than Western Europe.

The cautious nature of scientists leads them to emphasize that there is still room for discussion about whether the recent warming is primarily caused by the burning of fossil fuels and deforestation. However, it is evident that the atmosphere is heating up and a majority of the trapped heat from greenhouse gases is being absorbed by the oceans.

A recent research conducted by Australian scientists in September revealed that the prevailing wind patterns of the hemispheres in the past two years would typically result in higher-than-normal sea ice extent. However, they observed that this correlation seems to have been disrupted, likely due to an increase in ocean temperature between 100 and 200 meters below the surface.

Various experts have varying methods of explaining the decrease in sea ice. According to Tony Press, a former leader of the Australian Antarctic Division, it cannot be predicted with statistical accuracy.

What is the significance of this statement? “There is a possibility of it recurring, but there is also a significantly high likelihood that the sea ice in Antarctica has entered a new phase,” stated Press. “It would not be unreasonable to express concern about this.”

Scientists predict that a continual decrease in sea ice will hasten the warming of the ocean, as dark water absorbs more heat compared to ice. This will lead to a faster increase in global sea levels by eliminating a protective barrier for the continent’s ice shelves. Additionally, the decline in sea ice will have an immediate effect on various species that depend on it for sustenance, reproduction, and shelter. This includes not only penguins, but also krill, fish, and seals.

Sea ice on the coast of the Antarctic Peninsula and a map from the University of Colorado National Snow and Ice Data Centre showing the extent of sea ice on 24 September 2023.

According to Press, who is now a part-time professor at the University of Tasmania, the recent changes should be viewed as a significant event that will have a worldwide impact. He believes that the signs of a decrease and potential failure of the Southern Ocean’s overturning circulation should serve as a warning for us to take action.

The circulation that causes overturning begins in the frigid and compact waters below 4,000 meters of the Antarctic continental shelf. This process reaches all the ocean basins, supplying oxygen to the depths and nutrients to the surface. Researchers from Australia discovered that the melting of glacial ice in Antarctica is already decreasing water density and hindering the circulation.

Matt England, a researcher in oceanography at the University of New South Wales and one of the authors of two studies on overturning circulation, suggests that the decrease in circulation could have long-term consequences over the span of centuries, impacting temperature, oxygen levels, nutrient availability, and carbon reserves. However, he expresses greater worry for the immediate future, particularly in the next few decades.

‘Incredible geopolitical consequences’

According to Press, the possible consequences have a wide impact. For example, consider fish populations. Press explains that the global population relies on fisheries for food and nourishment. If these fisheries shift towards the northern and southern regions, away from the equator where most of the world’s population lives, there could be significant geopolitical implications.

Numerous researchers stress the importance of leaders comprehending the worldwide impact of current events and the magnitude of resources and effort that will be necessary to comprehend them.

According to Kaitlin Naughten, a researcher in ocean modeling at the British Antarctic Survey, the research suggests that the west Antarctic ice shelves will inevitably experience more melting. Naughten also warns that the distance and lack of human habitation in Antarctica does not mean that its effects will not be felt.

She emphasizes that she does not wish to perpetuate the negative outlook. While limiting the use of fossil fuels may not prevent the collapse of the west Antarctic ice sheet, taking decisive action can prevent other climate consequences. According to her, east Antarctica has a significantly larger amount of ice than west Antarctica and is expected to remain stable as long as emissions do not significantly increase.

Abram is currently dedicating her summer to studying this topic. In November, she was getting ready to journey 500km in order to extract a sample of ice from Denman glacier. The objective is to analyze how the climate of the last millennium compares to our current climate.

Denman glacier is part of the massive east Antarctic ice sheet, which until a few years ago scientists had thought was largely immune from global heating. As Naughten says, it is still considered likely to mostly hold steady if the world can get fossil fuels under control.

However, concerning the Denman glacier, there are alarming indications. According to Abram, the ice sheet’s altitude is decreasing and there are indications of ice loss, leading to a rise in sea levels.

If this seems tiring – another concern to add to the list in Antarctica – Matt England can understand.

He states, “Examining the findings is quite jarring.” “In my opinion, by 2023, I anticipate that all concerns regarding the immediacy of this issue will be resolved.”

Source: theguardian.com