[ad_1]
But not this year. For the first time since records were kept, open waters still wash this coastline in late October, although snow is already falling there.
“In one sense, it’s shocking, but on the other hand, it’s not surprising,” said Walt Meier, a research scientist at the University of Colorado Boulder’s National Ice and Snow Data Center (NSIDC). In the last 40 years, unprecedented events driven by climate change like this have become the new normal in the Arctic, which is warming much faster than the rest of the planet.
While weather patterns on top of the world vary, the overall changes are dramatic, occurring so rapidly that the region may be entering a “new Arctic climate regime,” says Laura Landrum, oceanographer at the National Center for Atmospheric Research (NCAR). from Colorado. . The Arctic is moving from a mostly icy state to a whole new climate, and it is affecting the entire planet, he said.
Meier calls the Arctic the “climate change benchmark climate” because it is a place where a small rise in temperature has a real impact: a change from -.5 ° C to .5 ° C (31 ° F to 33 ° F) it’s the difference between ice skating and swimming, he said, while a couple of degrees warmer in Florida aren’t even noticeable.
Comparison of autumn sea ice formation during the first half of October 2012 (the record year for loss of sea ice extent in the Arctic) and in 2020 (second place in loss of sea ice extent). The satellite record dates back to 1979. @Icy_Samuel, data provided by NSIDC
An extreme year in a region known for extremes
It’s been a great year in Siberia, on land and off the Arctic coast. The first six months were extraordinarily warm and the sea ice began to melt early. In May, fires were burning in areas of permafrost that are generally frozen throughout the year. In June, temperatures reached a record 38 ° C (100 ° F), and by September, flames incinerated about 14 million hectares (54,000 square miles) of tundra, an area the size of Greece.
A combination of changeable weather and peculiar weather is now preventing this fall’s freeze. Siberian Sea temperatures are higher than usual due to extreme weather events this year. The heat wave warmed the many rivers that flow into the Arctic Ocean and also caused an early thaw. With no ice and snow acting as a mirror, reflecting the sun’s heat back into the atmosphere, the dark ocean absorbed additional heat during the summer. Much of the remaining ice disintegrated. Then, in September, unusually strong warm winds blew from the south, pushing the newly formed ice out to sea.
In the past, a change in the winds wouldn’t have mattered much. In the 1980s, Igor Polyakov, a climate scientist at the University of Alaska, recalls being part of expeditions that landed small seaplanes on sea ice to study the Siberian Arctic. He described the Laptev Sea as a dazzling solid white landscape dotted with pastel-tinted ice – pink, light blue, and green. Since the region’s deeply cut gulfs and bays are located in the shallow waters of the continental shelf, most of them remained frozen.
But in the summer of 2002, the sea ice was less stable, and today icebreakers can traverse the region through open water. “The changes are dramatic,” he said. “It happened in front of our eyes. Now in the summer, there is no ice at all for thousands of miles, sometimes as far north as the 85th parallel.” That is five degrees from the North Pole.
In the 1980s, about 80% of the Arctic Ocean and surrounding seas were frozen in thick “old ice” that mainly survived the summer thaw, said James Overland, an oceanographer with the US National Oceanic and Atmospheric Administration. . (NOAA) that has studied the Arctic for decades. “Now a lot of that has to re-freeze every winter. We didn’t expect to see this so soon.”
Arctic sea ice extent on October 25, 2020 was at a record low of 5,613 million square kilometers as of this date, beating the 2019 record of 6,174 million square kilometers. NSIDC ChArctic
A dangerous cycle
On the other side of the Arctic, the ice is now melting earlier, freezing later, thinning, and in many places completely disappearing.
Thinner ice is less resistant. Imagine ice cubes in a glass. Chunks last longer and melt more slowly than ice chips and chips. They all disintegrate faster in a hotter liquid. This is a big problem in the Arctic, where vast stretches of open blue water absorb heat from the sun during the summer, when the sun never really sets. Those warm waters flow under the ice to melt it from below.
This year, the overall health of sea ice was dismal: The end-of-summer low was the second-lowest amount of sea ice in 42 years, Landrum said. Measurements by NASA and the NSIDC found it to be approximately 2.6 million square kilometers (1 million square miles) lower than the 1981-2000 average. NASA satellite data shows a general downward trend in Arctic ice it is 12.9% per year on average.
This year’s average global temperature will be among the warmest on record, the researchers say. Current models predict that the Arctic will be ice-free in summer between 2040 and 2050. Overland believes this so-called Blue Ocean Event (BOE) could come even earlier.
Many factors are colliding that could accelerate the massive melt. New feedback loops continue to emerge that exacerbate and accelerate changes. For example, the first climate models did not take into account methane, a powerful greenhouse gas, which is released into the atmosphere due to the melting of permafrost. The tundra is now believed to emit between 300 and 600 million tons of carbon a year, the equivalent of driving between 65 and 129 million cars for a year.
The Arctic appears to be shifting to an entirely new climatic state due to rapid warming. The extent of sea ice in late summer, when it reaches its minimum each year, has already entered a statistically different climate, with air temperatures at the surface and the number of days with rain rather than snow also beginning to change. Simmi Sinha, © UCAR
Likewise, thick ice that withstood strong winds and storms decades ago is now thin and can be severely damaged by such storms, amplifying unique extreme weather events. Then there is “Atlantification,” the increasing intrusion of the salty and temperate waters of the Atlantic Ocean into colder Arctic seas.
Changes in the Laptev Sea, long known as an Arctic “ice factory,” add another worrying factor. In the past, the sea ice created there generally moved with the wind and ocean currents, traveling over the North Pole towards Greenland. Depending on changing conditions, that ice was trapped for years in a slowly turning gyre in the Beaufort Sea; ended off the coast of Greenland; or piled up on the north coast of the Canadian archipelago, building ridges of ice that rose 12 to 30 feet (3 to 9 meters) high, multi-year ice that resisted melting.
That system no longer works as it once did, with the Laptev Sea now turning blue water every summer, the “ice factory” largely closed, and Arctic sea ice for several years at an all-time low and still falling.
An interconnected planet
The polar bear has become the symbol of the impacts of climate change on wildlife. But Ursus maritimus is not the only victim; Cascading effects along the Arctic food chain are affecting everything from plankton to seals, globally important fishery species such as pollock, whales, musk oxen and other cold-climate mammals.
In Siberia, reindeer starve to death in winter. The “whiplash” brings rain, in what should be the icy polar night. Falling rain freezes on top of the snow cover, forming a thick layer of ice that makes it impossible for reindeer to dig into the grass and plants underneath; many are now starving. These arctic warm spells, once rare, are now common.
Indigenous peoples are also suffering. Without the proper ice shelves, they find it increasingly difficult to hunt down the walruses and whales that support them. Coasts are eroding as sediments held together by permafrost lift off. And rising sea levels are flooding coastal villages.
Worse still, rapidly escalating climate change in the far north is being exported to the rest of the world: Earth’s biomes are interconnected. “You can’t alter one system without affecting others,” explained Mark Serreze, a research scientist at the NSIDC. “What happens in the Arctic does not stay in the Arctic, and changes are unfolding faster than our ability to keep up.” Serreze, in his 2018 book framing the problem, called the north pole region “The New Brave Arctic.”
Serreze points out that the Arctic covers a huge area; It is the size of the lowest 48 US states combined. Amplified Arctic warming alters global climate and impacts the rest of the planet, changing climate, ocean patterns, and the jet stream.
Intense storms, droughts and heat waves, once every 100 to 500 years of extreme weather events, now occur regularly around the world, with devastating impacts on people, economies, and ecosystems. This year alone, for example, there were record massive wildfires in California, Colorado, Siberia and Brazil, and no one yet knows how this fall’s delayed Arctic freeze could affect the planet’s next climate.
A fire in the northern forest of Krasnoyarsk, Siberia, in July 2020. Greenpeace International
Julienne Stroeve, who specializes in sea ice research at NSIDC, adds another potential serious impact to the list: threats to our food supply. “What is projected to happen in the agricultural sectors is not good news … We will live on a very different planet if we continue to add greenhouse gases to the atmosphere,” he said. “We are conducting this experiment in the dark and we do not yet know the real implications.
Stroeve is desperate to inform people of the urgency: “How do you sell climate change as an emergency as big as COVID-19? Except it will kill a lot more people.”
She believes that we can unite. If we can produce a COVID-19 vaccine in record time and heal the ozone layer through the Montreal Protocol, Stroeve believes that “we have the ability to change the course of this train.”
Published with permission from Mongabay.
From the articles on your site
Related Articles on the Web
[ad_2]
