"When I was your age, I had to ski 30 kilometers to go to school," said Hannell Kohonen, a research professor at the Finnish Meteorological Institute (FMI). .
Such memories and scenes may soon be a thing of the past, Kohonen said during a press conference on the state of Finland's climate on August 11, 2021.
Finland is one of the countries near the North Pole that has changed its climate in recent years.
"It is obvious that the winter in southern Finland has been warmer in recent years, and the amount of snowfall is also decreasing." Mika Rantanen, a researcher at the Finnish Meteorological Institute, told the Beijing News that living in southern Finland, he could feel the Arctic effects of warming.
In recent years, the temperature in Helsinki, the capital of southern Finland, has continued to rise.
Anne Bogstrom, also a researcher at the Finnish Meteorological Institute, combed through the research data and found that Helsinki's 1991-2020 winter was significantly warmer than 1961-1990.
Finland is not alone.
With the intensification of climate warming, many countries near the Arctic frequently experience abnormally high temperatures.
On July 4, 2019, the temperature at Anchorage International Airport in Alaska, USA reached 32°C, breaking a 50-year high temperature record; on June 20, 2020, the temperature in Verkhoyansk, an arctic town in northeastern Siberia, Russia reached 32°C 38°C, breaking the record for the highest temperature ever recorded in the Arctic Circle; in July this year, the temperature in the Arctic Circle soared to 32.5°C, and scientists in the Arctic even played ice volleyball in short-sleeved shorts.
Behind the warming of the Arctic is related to global warming.
The impact of warming in the Arctic, whether it is melting glaciers and sea ice, or the possibility of "awakening" viruses and bacteria that have been sealed here for many years, will also spread from the Arctic to the world.
What can we do about Arctic warming?
Rick Toman, a climate scientist at the International Arctic Research Center (IARC), told the Beijing News, "Arctic warming is part of the global climate system, and every effort to reduce greenhouse gas emissions helps prevent Arctic warming from intensifying. ".
Arctic warming almost 4 times faster than global average
Rantanen has been concerned with Arctic warming since he began studying meteorology about a decade ago.
Two years ago, in the summer of 2020, a strong heat wave in the Arctic region made Arctic warming a hot topic on major media platforms. There is a saying that "the rate of warming in the Arctic is twice the global average" caused Ranta. Ning and other researchers.
"We're frustrated by this claim, because the data clearly shows that the Arctic is warming almost four times faster than the global average," Rantanen said, leading them to investigate the claim further.
What researchers such as Rantanen further studied is actually the extent of the "Arctic amplification effect".
The Arctic amplification effect means that the Arctic is warming much faster than the rest of the world, and the changes are much more pronounced, Toman said.
Due to the unique Arctic amplification effect, the Arctic region has become one of the most significant regions of global warming.
The British Broadcasting Corporation (BBC) quoted the observation data of the National Aeronautics and Space Administration (NASA) as saying that from 1960 to 2019, the global average temperature has generally increased by about 1°C, which is about 4°C higher than that at 90° north latitude. .
But scientists from many countries are still divided on the extent of the Arctic amplification effect, that is, how much faster the Arctic is warming than the rest of the world.
Most scientific literature and media reports have previously mentioned that based on existing climate models, the rate of warming in the Arctic is 2 or 3 times the global average, but this number may actually be higher.
After about two years, Lantanen and other researchers published an article in the famous journal "Nature Communications-Earth and Environment" on August 11, 2022 local time, saying that by analyzing the observation data of the Arctic Circle over the past 43 years, it was found that the Arctic The rate of warming is indeed higher than previously reported in the scientific literature and generally reported.
Specifically, between 1979 and 2021, most of the Arctic Ocean warmed at a rate of 0.75°C per decade, which is almost four times the global average.
Thus, existing climate model projections may generally underestimate the Arctic amplification between 1979 and 2021.
Underestimating the Arctic amplification effect is not conducive to people's objective understanding of the Arctic warming, but its impact has already emerged, not only impacting the indigenous peoples and ecosystems in the Arctic, but also having a profound impact on the global climate system and environment.
Warming Arctic affects flora and fauna
What Rantanen can say for sure is that "the Arctic is warming faster than the rest of the world, and it is already having a huge impact on Arctic societies and ecosystems."
Toman also said that since the 1990s, the Arctic climate has warmed rapidly, and after 2000, the warming has been very pronounced.
Indigenous peoples in arctic communities have had to adjust their way of life to adapt to a warming climate.
Some traditional routes across sea ice are no longer safe, a study by the University of Leeds in the U.K. of Inuit people living in Canada's Labrador region around the Arctic has found.
Typically, Inuit snowmobiles traverse sea ice, rivers and paths on frozen ground to and from settlements and traditional hunting grounds, but in some places the ice has become too thin to support snow. Motorcycle traffic.
Also in the Labrador region, the Inuit face food supply problems.
The previous way of obtaining food through hunting has become increasingly difficult, and they have to rely more on processed food.
According to the WWF Arctic Programm, people in many parts of the Arctic cannot afford food substitutes for traditional local foods.
To adapt to the rapid warming climate, and the flora and fauna of the Arctic region.
Toman explained that animals at more southerly latitudes (land and sea) are migrating northward, while species in the Arctic are either migrating north or confined to a small area where their habitat is changing more slowly.
Even polar bears at the top of the food chain are not immune.
Steve Armstrong, chief scientist of the International Polar Bear Organization, told The Associated Press that polar bears used to hunt in shallow waters near shore for food, but in recent years the summer sea ice has receded far from shore, forcing polar bears on the ice. Drift into deep water, sometimes nearly a mile deep (about 1600 meters), but there is no prey there.
In addition to animal migration, Toman points out, plants also migrate.
A report by The Guardian in early 2022 stated that the forest line in the north was out of control.
Under the influence of climate warming, the northern forest line is moving faster to the north, putting green clothes on the white polar regions.
In the past, the forest moved forward about a few centimeters per year; now, the movement is accelerating, shifting northward at a rate of 40 to 50 meters per year.
In Europe near the Arctic, birches are particularly prominent.
Sea ice declines, Arctic waterways "hot"
What worries Rantanen is that sea ice is an important factor in the magnification of the Arctic.
As sea ice shrinks, the ocean will absorb more of the sun's heat, causing the Arctic to get warmer.
Extensive sea ice covers the Arctic Ocean and usually freezes in winter, and some of it melts in summer.
In recent decades, the extent of sea ice has been shrinking.
Between 1981 and 2010, Arctic sea ice extent decreased by at least 13.1 percent every 10 years, on average, according to NASA.
Rantanen predicts that there may be sea ice in the coming winters, but the smallest summer sea ice could disappear completely this century.
The melting of sea ice will indirectly contribute to global sea level rise.
Sea ice forms and melts in the ocean and does not directly contribute to sea level rise.
By analogy, sea ice is like ice cubes in a glass of water, melting does not directly change the water level in the glass.
However, Eric Rignot, a professor of earth system science at the University of California in the United States, analyzed the American popular science magazine "Scientific American" that sea ice melting will indirectly lead to sea level rise. The principle is that sea ice can reflect solar radiation back to the atmosphere. , causing the Arctic atmosphere to heat up.
As sea ice shrinks and ocean water expands, water that is darker than sea ice absorbs more solar radiation, pushing up the overall temperature in the Arctic, further melting more land ice, and indirectly raising sea levels .
The land ice mass that Rignot refers to mainly refers to glaciers.
Unlike sea ice, glaciers form on land, and their melting can directly cause sea level rise.
Global sea levels are now rising by an average of 3.2mm per year, and are expected to rise by a total of 0.2m to 2m by 2100.
Andre Dutton, an assistant professor of geology at the University of Florida, said the Greenland ice sheet in the Arctic places the highest risk of sea level rise.
Most of the land ice in the Arctic is in Greenland, with a cumulative volume of 2.96 million cubic kilometers.
If the entire Greenland ice sheet melted, sea levels would rise by an average of 7 meters, and many coastal cities such as Mumbai would sink to the bottom of the sea.
As the sea ice melts, the Arctic waterway is gradually smoothed, and its shipping value is highlighted.
According to Xinhua News Agency, between 2013 and 2020, the number of vessels passing through the Northern Sea Route increased from 635 to 1,002, and the total cargo volume increased from 1.36 million tons to over 33 million tons. important supplement.
In this regard, the BBC reported that some people believe that this will completely change the global shipping industry, but others think it is a potential disaster.
Environmental groups are concerned that the opening of shipping routes and increased traffic in the Arctic Ocean could disrupt the slow-growing, long-cycle Arctic marine biosphere.
Of particular concern is the potential for huge pollution if a freighter were to have an accident in the Arctic Ocean.
Permafrost may release ancient virus
Under the influence of Arctic warming, it is not just sea ice and glaciers that are melting, but permafrost is also at risk of thawing.
Permafrost, also known as permafrost, refers to land below the Earth's surface that has been frozen for at least two consecutive years, and whose temperature remains at 0°C or lower, most commonly found in high mountains and high latitudes (near the North and South Pole).
According to the Arctic Institute, an international think tank, nearly a quarter (24%) of the northern hemisphere's landmass is covered with permafrost, which stores nearly half of the world's organic carbon.
The thawing of permafrost has caused great safety hazards to various infrastructures on the permafrost layer.
Some infrastructures in countries around the Arctic are built on permafrost. When permafrost freezes, it is harder than concrete, but after melting, the infrastructure such as houses and roads in the villages have been or will be damaged, 2022 The U.S. Department of Defense's report in early April on the rupture of runways and sinking of foundations at Arctic military bases due to climate change is an example.
A study in the journal Nature, titled "Impact of Permafrost Degradation on Infrastructure," also showed that up to 80 percent of urban buildings in the Arctic-circumerating country Russia reported damage as another example.
The researchers in the research paper predict that infrastructure damage is expected to continue, with 30 to 50 percent of critical infrastructure around the Arctic likely damaged by 2050.
At the same time, the thawing of permafrost will also emit a lot of greenhouse gases and exacerbate climate warming.
The permafrost holds a large amount of organic carbon, which may be converted into carbon dioxide and methane and released as the permafrost melts.
Scientists from Finland, Canada, the United States, Sweden and Germany estimate that the permafrost in the Arctic stores nearly 1.7 trillion metric tons of frozen-thawed carbon, and the release of even a fraction of that carbon has the potential to accelerate global warming.
Even more worrying is that by 2100, nearly two-thirds of the near-surface permafrost may disappear, and other microorganisms such as viruses, bacteria and fungi that have been frozen for hundreds of billions of years may also threaten the future survival of mankind. .
Ancient anthrax spores may have been responsible for the death of a 12-year-old boy in Siberia in 2016, according to an article titled "Threats to the future come from the past" on the website of the National Center for Biotechnology Information, and that scientists were able to extract information from ancient frozen biological samples. Reconstructing the genomes of smallpox and the Spanish flu has heightened concerns that thawing permafrost could lead to the emergence of more dangerous or deadly germs.
American virologist Jean-Michel Clavery pointed out that "the real danger is not the thawing of the permafrost itself, but the fact that humans are now beginning to develop the Arctic region and dig the permafrost, which will become the source of disaster."
Extreme weather in North America, Europe may be linked to Arctic warming
As an atmospheric scientist, Rantanen is most interested in how Arctic amplification affects weather and climate beyond the Arctic.
"There are studies showing that Arctic warming is weakening the jet stream, leading to more extreme weather in the mid-latitudes," he said.
According to the National Weather Service's definition, the "jet stream" Rantanen refers to is a relatively narrow band of strong winds high in the sky, driven from west to east by the temperature difference between the equator and the Antarctic and North Pole.
Normally, the large temperature difference between the equator and the North Pole keeps the jet stream relatively stable, but as the North Pole heats up much faster than at other latitudes around the globe, the temperature difference between the North Pole and the lower and middle latitudes decreases. Small, weakened jet streams increase the risk of extreme weather in mid-to-high latitudes.
Relevant research has been reflected in the research reports of the British "Guardian" and other foreign media, and the American Meteorological Society.
Among them, the British "Guardian" pointed out that the warming of the Arctic seems to induce extreme weather in places such as Europe and the United States by changing the "jet stream" that surrounds it, such as more severe heat waves, more frequent precipitation and more prolonged droughts.
However, there are also studies that suggest that it is difficult to find a strong direct link between complex weather systems and Arctic warming.
Rantanen also mentioned that there is "no consensus in the scientific community on whether the warming of the Arctic will lead to more extreme weather in the mid-latitudes."
While discussions about Arctic warming continue, its effects are not limited to the Arctic.
Many experts believe that the general background of Arctic warming is global warming, and global warming is mainly caused by human activities, and human beings should take action to deal with it.
"While natural climate change is also at play, climate change is primarily caused by human emissions of greenhouse gases," Rantanen said. "We can take action to prevent climate change from increasing. We have no other choice than that."
Thomman agrees, "The Arctic is connected to and part of the global system, and everything people can do to reduce greenhouse gas emissions will help combat Arctic warming."
Beijing News reporter Zhu Yuehong