Antarctic sea ice, the “earth’s protective umbrella,” is melting away.
According to the U.S. National Snow and Ice Data Research Center, the Antarctic sea ice area this winter reached its peak on September 10, reaching 16.96 million square kilometers. This number sets a record for the peak Antarctic winter sea ice area since satellite observation data began to be available in 1979, and is 1.03 million square kilometers less than the historical low in 1986.
Compared with the same time point in 2022, the sea ice area has shrunk by more than 1.5 million square kilometers, which is equivalent to the size of Australia’s Northern Territory.
In this regard, Walter Meyer, a senior scientist at the research center, exclaimed that this year is an “extreme record-breaking” year – this very rare anomaly is likely to occur within hundreds of years. It only happens once in ten thousand years.
As a key component of the polar climate system, the melting of sea ice may trigger a chain reaction around the world. So, what kind of butterfly effect will come?
The increasingly unpredictable Antarctic ecology
Regarding the historic decline of Antarctic sea ice in recent years, the British “Independent” believes that global warming is mainly responsible. The argument of the article is that in 2020, it was detected that Antarctica was hit by a rare heat wave, and the maximum temperature increased by about 9.2 degrees Celsius compared with previous years.
Indeed, there are similar cases that can be cited as evidence. On March 15, 2022, “Conger”, a huge ice shelf in East Antarctica, completely collapsed. The ablation area was equivalent to the combined area of Huangpu District and Baiyun District of Guangzhou City, China. This is also a major polar event that was completely beyond scientists’ expectations – the ice shelf is located in the driest and coldest area of the Antarctic continent and was originally very stable.
Matt King, a professor at the University of Tasmania, analyzed that at that time, the temperature in some parts of Antarctica was nearly 40 degrees Celsius higher than the monthly average temperature. The extreme heat wave was likely to be the “final A fatal blow”.
Ariane Prich, a sea ice researcher at Monash University in Australia, has proven through research that the warming of the Southern Ocean caused by the greenhouse effect is another factor leading to the decrease in sea ice. He described such a vicious cycle: According to the “albedo effect” in which white reflects sunlight more than dark colors, the sea surface that has lost floating ice due to warming will absorb more sunlight, triggering a new round of seawater warming and ice Body melts. Therefore, once polar sea ice, one of the most sensitive “regulators” of the global climate, is lost, Antarctica will transform from the “Earth’s refrigerator” into the “Earth’s radiator.”
The Antarctic system has a high degree of complexity that far exceeds current understanding.
Under this situation, Dr. Caroline Holmes of the British Antarctic Survey is worried that as summer progresses in the Southern Hemisphere, sea ice shrinkage will become unstoppable. “The game has changed,” Ted Scambos, a glaciologist at the University of Colorado Boulder, even told CNN: “We won’t be able to do this for a long time to come, maybe forever. “To see the Antarctic system return to what it was 15 years ago is the irreversible new normal.”
However, some scientists hold a more conservative and cautious attitude, believing that it is too early to draw pessimistic conclusions. Remote sensing scientist Dr. Peter Fretwell compared the two poles of the earth and found that unlike Arctic sea ice, which clearly shows a linear trend of gradually decreasing over time, the area of Antarctic sea ice has been in a stable state in the early years, and even decreased for a time. There was a “warming paradox” of slow growth, and it was not until after 2016 that an unprecedented abnormally low curve emerged.
It can be seen that the Antarctic system has a high degree of complexity that far exceeds the current cognitive scope. Therefore, in the face of the sudden decline in Antarctic sea ice area, Professor Martin Siegert, a glaciologist at the University of Exeter, told the media that analyzing the causes and predicting the direction at the moment are talk that is difficult to say with certainty.
Recently, the team of young associate researchers Guo Yuanyuan and Professor Wen Zhiping of the Department of Atmospheric and Oceanic Sciences of Fudan University published a paper in the top international journal “Geophysical Research Letters”, clearly proposing for the first time that the Antarctic summer in the past thirty years has The observed fact is that sea ice extent variability is increasing. An Antarctic with increasingly violent oscillations and unpredictable changes. This may be the only clear fact at the moment.
Emperor penguins face reproductive crisis
Sudden changes in the Antarctic environment have had a major impact on the activities of wildlife: Antarctic krill, one of the key food sources for whales in the area, has significantly moved and shrunk southward.
And animal populations that rely on sea ice for breeding are the first to bear the brunt, such as emperor penguins. The mating, egg laying, and incubation of this creature all take place on the sea ice. After that, the children can survive independently from their parents. In other words, from March to January of the next year, the sea ice in the emperor penguin habitat must remain stable.
Once the sea ice melts during this period, the immature chicks will fall into the sea and drown or freeze to death because they do not have flippers for swimming and waterproof adult feathers. Even if the chicks manage to find a foothold on floating ice fragments, they will become separated from their parents, lose food, and eventually starve to death.
Since satellite imaging monitoring was put into use in 2009, several isolated incidents of terrestrial ice shelf retreat, resulting in reproductive failure, have been discovered across Antarctica. Since 2018, 30% of the more than 60 known emperor penguin colonies on the Antarctic continent have begun to suffer widespread impacts from partial or complete reduction of sea ice. Last year in particular saw the most widespread regional reproductive failure on record.
According to an article published in the British magazine “Earth and Environment Letters”, in the Bellingshausen Sea area where the Antarctic sea ice retreated most severely last year, scientists observed 4 of the 5 emperor penguin breeding areas. Of the approximately 10,000 chicks, only 820 on Rothschild Island in the far north may survive.
Biologist Ratcliffe exclaimed that this catastrophic “complete failure of reproduction” should serve as an “early wake-up call” to pay attention to the survival situation of species on the ice. Currently, emperor penguins are listed as a “near-threatened species” by the International Union for Conservation of Nature (IUCN). However, if the bad momentum cannot be braked, it is estimated that more than 90% of emperor penguins will face the tragedy of extinction by the end of this century. It has been proposed that it should be added to the list of “vulnerable species” with more urgent protection needs.
Fortunately, the loss of sea ice will not endanger the survival of adult emperor penguins, so researchers are also pinning their hopes on next year’s breeding season. The key depends on whether the emperor penguin colony can quickly adapt to the current situation that the existing breeding base may be fleeting and unreliable, and switch to a migration mode to explore new and safer areas.
In recent years, studies have indeed discovered that emperor penguins have developed a new breeding behavior—in years when sea ice forms later, they will go to ice shelves to breed. Compared with ice floes on the water, ice shelves are the portion of the ice sheet connected to the continental shelf that extends toward the ocean. They are much thicker than sea ice and are less susceptible to temperature changes.
But the “Sword of Damocles” hanging above the heads of the emperor penguins has not been lifted – how to enter the ice shelf is a big test for the emperor penguins. Facing an ice shelf with huge ice cliffs, emperor penguins without the ability to climb must find roundabout passages such as gentle slopes formed by ice streams to reach their destination. Therefore, there is a question mark as to whether this plan can alleviate the emperor penguin breeding crisis.
Not to mention, the emperor penguin is also an animal that “relocates to its new home”. In Halley Bay, the second largest emperor penguin breeding ground in Antarctica, there were originally about 20,000 pairs of emperor penguins. After experiencing breeding failure, most of the population chose to move to a new breeding ground 56 kilometers away. However, follow-up research found that until 6 years later, a small number of emperor penguins still insisted on returning to their original homes.
In short, as Rod Downey, head of WWF’s polar program, emphasized: “If humans cannot prevent the continued rapid decline of sea ice, then Emperor Penguins will not have a real refuge.”
Human beings have to “grasp” this slender chain of icebergs with their fingernails.
Will coastal cities be flooded?
In addition to endangering biological populations, the disappearance of the buffer “insulating layer” of sea ice will cause Antarctic glaciers to be directly exposed to warm seawater and continue to melt, which is equivalent to indirectly pressing the accelerator button for sea level rise.
In fact, the Antarctic glacier crisis has long been known. The vast Thwaites Glacier is one of the fastest-melting glaciers in Antarctica. In 2014, American researchers warned that the ice sheet had “unstoppable” collapse. By November 2021, satellite images showed that several large cracks across the ice wedge were found on the ice shelf supporting the Thwaites Glacier. Once the ice shelf breaks, the glacier will melt at more than three times the rate. .
Data show that since the 1980s, Thwaites Glacier has lost approximately 595 billion tons of ice, and the amount of melted water accounts for 4% of global sea level rise. There is an apt metaphor that describes Thwaites Glacier as being like the cork on a red wine bottle. Once it collapses, it will cause the remaining parts of the ice sheet on the west side of Antarctica to pour out and pour into the sea.
Therefore, Thwaites Glacier is also known as the “Doomsday Glacier” – scientists call on humans to “hold on tightly with their fingernails” to this slender iceberg chain, because when it melts That time is when the end comes.
According to 2010 statistics, about 10% of the world’s population (approximately 600 million) live in low-lying areas below an altitude of 10 meters, facing the risk of flooding caused by rising sea levels, and other problems. More severe storm surges in the region. In the same year, the international environmental organization Greenpeace issued an assessment: In Asia, for every one meter of sea level rise, a city may be submerged.
Globally, the city with the highest risk of such disasters is Manila. It is predicted that by 2030, the probability of a once-in-ten-year major flood in the city will continue to rise, and nearly 87% of the city’s area will be swallowed up by floods.
The media “Wales Online” published a report on September 24 that after the warning about the melting of Antarctic sea ice came out, the British Meteorological Office issued a follow-up forecast based on the new map organized by the Climate Center — By 2050, large swaths of eastern Britain, and small pockets of western Europe, could sink below annual flood levels; sea levels could rise a further 3.7 feet (1.12 meters) by the end of the century.
In this critical situation, mankind urgently needs to take action to save itself. Although it is not yet possible to conclude that greenhouse gas emissions are the “culprit” causing the massive melting of Antarctic sea ice, as the British “Daily Mail” said: “The inability to attribute cannot be used as an excuse not to stop burning fossil fuels.”
In addition, scientific experiments in the Arctic have also proven that reversing climate warming is indeed the entry point to restore polar sea ice. Although it is not yet certain whether this method is applicable in view of the uniqueness of the Antarctic environment, it still brings a glimmer of hope to the rapidly declining Antarctic ecology.
After all, time is really running out for humans and animals.