On March 18, 2022, scientists at the Concordia research station on the eastern Antarctic plateau documented a remarkable event. They recorded the largest temperature jump ever measured at a meteorological center in the world. According to the instruments, that day the region experienced an increase of 38.5 degrees above the seasonal average: a world record.
This surprising jump in the coldest place on the planet left polar researchers struggling to find words to describe it. “This is truly mind-blowing,” said Prof Michael Meredith, scientific lead at the British Antarctic Survey. “Such a big jump in sub-zero temperatures is tolerable, but if there was a 40C rise in the UK right now, this would push temperatures above 50C on a spring day, which would be fatal for the population.”
This surprise was shared by glaciologist Prof Martin Siegert from the University of Exeter. “No one in our society thought anything like this could happen. This is extraordinary and truly worrying,” he said. Observer. “We now have to grapple with something completely unprecedented.”
Poleward winds, which previously barely penetrated the atmosphere above Antarctica, are now increasingly carrying warm, moist air from lower latitudes, including Australia, deep into the continent and are to blame for the dramatic polar “heat wave,” scientists say. He hit Concordia. However, it is not yet clear why these currents can penetrate so deep into the continent’s airspace.
Scientists also discovered that this massive temperature increase was not an isolated event. They have been grappling with an increasing number of reports of disturbing meteorological anomalies across the continent for the past two years. As the glaciers surrounding the West Antarctic ice sheet increasingly lose mass towards the ocean, levels of sea ice floating in the oceans around the continent have fallen dramatically and remained stable for more than a century.
These events have raised fears that Antarctica, once thought to be too cold to experience the first effects of global warming, is succumbing dramatically and quickly to ever-increasing levels of greenhouse gases that humans continue to pump into the atmosphere.
These dangers were highlighted in a paper published last week by a team of scientists led by Will Hobbs of the University of Tasmania. Climate Magazine. After examining recent changes in sea ice cover in Antarctica, the group concluded that there was a “sudden critical transition” in the continent’s climate that could have repercussions on both local Antarctic ecosystems and the global climate system.
“Extreme lows in Antarctic sea ice have led researchers to suggest that a regime shift is underway in the Southern Ocean, and we found ample evidence supporting such a shift towards a new sea ice state,” Hobbs said.
The dramatic nature of this transformation is emphasized by Meredith. “Antarctic sea ice cover actually increased slightly in the late 20th and early 21st centuries. But it fell off the cliff in the middle of the last decade. “This heralds new ground with the Antarctic climate system, which could be very disruptive for the region and the rest of the planet.”
Siegert added that the continent is now catching up with the Arctic, where the effects of global warming have been experienced most intensely on the planet so far. “The Arctic is currently warming four times faster than the rest of the planet. But Antarctica has begun to catch up and is already warming twice as fast as the planet as a whole.”
The main reason why the Arctic and Antarctica are disproportionately hit by global warming is that the Earth’s oceans, warmed by the burning of fossil fuels, are losing sea ice at the polar tips. The dark waters that used to lie beneath the ice are exposed, and the sun’s rays are no longer reflected back into space. Instead it is absorbed into the sea, and the oceans there become even warmer.
“Essentially it’s a vicious cycle of warming oceans and melting sea ice, but the root cause of that is humanity, the constant burning of fossil fuels and the production of greenhouse gases,” said Meredith. “This whole business needs to be left at our doorstep.”
Researchers warn that the consequences of this meteorological metamorphosis could be devastating. If all the ice in Antarctica were to melt, it would cause worldwide sea levels to rise by more than 60 metres. Islands and coastal areas, currently home to most of the world’s population, will be submerged.
However, it seems unlikely that such an apocalypse will happen for a while. Antarctica’s ice sheet covers an area of 14 million square kilometers (about 5.4 million square miles), roughly the size of the United States and Mexico combined, and contains about 30 million cubic kilometers (7.2 million cubic miles) of ice; This is approximately 60% of the world’s fresh water. This vast blanket hides a mountain range almost as high as the Alps, so it will take a very long time for it to melt completely, scientists say.
However, as the ice sheets and glaciers in West Antarctica continue to shrink, there is a real danger that some significant sea level rise will occur in the next few decades. These are eroded from their bottoms by warming ocean water and may disintegrate within a few decades. If they disappear completely, sea levels would rise by 5 metres, harming coastal populations around the world. It is difficult to assess how quickly this will happen. The Intergovernmental Panel on Climate Change has said sea levels will likely rise by 0.3 to 1.1 meters by the end of the century. Many experts now fear this is a dangerous underestimation. In the past, climate change deniers have accused scientists of exaggerating the threat of global warming. But emerging evidence from Antarctica and other parts of the world makes clear that scientists are not exaggerating. In fact, they likely underestimated the threat humanity currently faces.
“In Antarctica, the picture is even more complicated because historically we have had trouble getting data,” Meredith added. “Because the continent is so remote and so hostile, we’ve never had much insight into the weather and ecosystem compared to the data we get from the rest of the world. Our records are relatively short, which means that the climate models we build, although very capable, are based on sparse data. They cannot cover all of physics, chemistry and biology. “They can make consistent predictions, but they no longer capture the kinds of extremes we’re starting to observe.”
But the challenges facing Antarctica are not just about humanitarian concerns. “We are already seeing serious ecological impacts that threaten to spread throughout the food chain,” said Prof Kate Hendry, a chemical oceanographer from the British Antarctic Survey.
Algae growing under and around sea ice in West Antarctica provide a critical example. Hendry added that this is starting to disappear with very serious consequences. Algae is eaten by krill, small marine crustaceans that are one of the most abundant animals on Earth and provide food for predators such as fish, penguins, seals and whales. “If krill start disappearing after algae, there will be all kinds of disruptions in the food chain,” Hendry said.
But the threat posed by the disappearance of krill goes even deeper. They play an important role in limiting global warming. Algae absorbs carbon dioxide. The krill then eat them and excrete them, which sink to the seafloor and remain there. Reducing levels of algae and krill will mean that carbon from the atmosphere will accumulate on the ocean floor and return to the atmosphere instead, remaining close to the sea surface.
“They act like a conveyor belt, taking carbon from the atmosphere to the deep ocean floor where it can be locked up. So if we start messing with this system, we could end up with a whole host of other knock-on effects in our attempts to deal with the impact of global warming,” Hendry added. “It’s a scary scenario. But unfortunately this is the situation we are facing now.”
Another victim of the sudden and devastating warming that affected the continent is its most famous resident: the emperor penguin. Last year, the Antarctic-only species suffered a catastrophic breeding failure because the sea ice platforms on which they were born began to break down long before the young penguins developed waterproof feathers.
“We have never seen emperor penguins fail to reproduce on this scale in a single season,” said Peter Fretwell of the British Antarctic Survey. “The loss of sea ice in this region during the Antarctic summer made the odds of survival of displaced chicks extremely low.”
Researchers say the discovery of the loss of emperor penguins shows that more than 90 percent of colonies will disappear by the end of the century if global warming trends continue at their current catastrophic pace. “The hatchlings can’t survive on the sea ice until they fly away,” said Meredith. “After that, they can fend for themselves. But the sea ice is breaking up before it gets to that stage, and now there are mass drownings. Penguin colonies are being destroyed. And that’s a tragedy. This is an iconic species that is a symbol of the new vulnerability of Antarctica and its ecosystems.”
The crisis facing the continent has widespread effects. More than 40 countries have signed the environmental protocol of the Antarctic Treaty, which is expected to protect against a number of different threats; Habitat degradation is one of the most important. The fact that the continent is now experiencing alarming changes in its ice cover, ecosystems and climate is a clear sign that this protection is no longer provided.
“The reason for this ecological and meteorological change lies outside the continent,” Siegert added. “This is because the rest of the world continues to emit large amounts of carbon dioxide.
“However, if countries are knowingly polluting the atmosphere with greenhouse gases and Antarctica is affected as a result, then there is good reason to argue that the treaty protocol has been violated by the signatories and their actions can be challenged legally and judicially. political reasons. “It will certainly lead to some tough meetings at the UN in the years to come.”