Another year after the Arctic melt

  • The extent of Arctic sea ice shrank to its lowest level in the summer this week – capping 2017 and 2018 to be the tenth lowest ever recorded. However, the last 16 consecutive years have seen the lowest ice area since satellite recording began. The extent, thickness and volume of Arctic sea ice continue a sharp downward trend.
  • Arctic air temperatures have been high this summer, with parts of the region experiencing unprecedented warming. Greenland saw air temperatures of 36 degrees Fahrenheit above normal in September. Canada’s Northwest Territories have seen record highs, reaching the 1990s in July. Sea temperatures also remained very high in many parts of the Arctic Ocean.
  • Scientists remain concerned that climate change is warming the Far North about four times faster than the rest of the planet, raising concerns about how polar warming will affect the jet stream in the atmosphere, intensifying catastrophic extreme weather events worldwide, Including heat waves, droughts and storms.
  • While an ice-free Arctic could happen as early as 2040, scientists stress that it doesn’t have to happen. If humanity chooses to act now to drastically reduce greenhouse gas emissions, then downward sea ice and volume trends will likely be reversed.

In August, I traveled by icebreaker Kinfish To the archipelago of Svalbard, north of the Arctic Circle. We were invited to the bridge while sailing the fjords near 80The tenth In parallel, I was stunned by the towering icy blue walls, but was confused by the map displayed on one of the ship’s screens. Our ship was shown sailing through a frozen, unnavigable sheet.

When I shared this story with Walt Meyer, chief researcher at the National Snow and Snow Data Center, he didn’t seem surprised. “Things are changing fast there these days,” he said. And fast, even polar ice mapping can’t keep up.

The spring-summer 2022 Arctic melt season, when the sun never sets and sea ice recedes, as days shorten rapidly, is over, with the Far North returning to complete winter darkness. It wasn’t a record-breaking or news-making year for low ice – Ranked tenthcoinciding with 2017 and 2018 – but it was another thaw season later.

Latest daily Arctic sea ice extension (JAXA AMSR2) for 2022 (thick red line). The dashed lines also show average sea ice extents from the 1980s, 1990s, 2000s, and 2000s. A thin white line is shown for 2012. Annual minimum ranges (2002-2021) are shown by scattering points in color indicating the total sea ice extent. picture Courtesy of Zachary Labe/Princeton/NOAA GFDL

The last 16 consecutive years were the lowest since 1979 when satellite tracking began, with The lowest level ever in 2012says Zachary Lapp, a postdoctoral researcher at Princeton University and at the National Oceanic and Atmospheric Administration (NOAA) Geophysical Fluid Dynamics Laboratory. Inclusive, Climate change is warming the Arctic Almost four times faster than the rest of the planet. But melting is not equal across the Arctic. The biggest overall factors affecting sea ice are air and sea temperatures, with winds and storms sometimes adding collateral damage.

In most parts of the planet, it was a hot, hot summer, with unprecedented heat waves Hong Kong And the India for a lot of Europeand the we. And on top of the world, too. Meyer says air temperatures over a “good part of the Arctic” have exceeded the 30-year average. Unprecedented heat in Greenland during the month of September and until 36°F (20°C) above normal, helped lengthen the melt season a bit: the average sea ice isotope is September 14; It came this year on September 18th.

Back in July, Canada’s Northwest Territories Grilled at extreme temperatures, which soared into the 1990s, breaking all-time highs. This record warmth has created countless melt ponds on the Beaufort Sea ice, which scientists are watching closely because they have held large amounts of “old” thick ice, which is more resistant to melting. Those melting puddles are eroding the ice from above.

Recently Posted Search in Scientific Reports It found that air temperatures in the northern Barents Sea region (northern Norway and Russia) from 1981 to 2020 were “exceptional,” even for the Arctic – temperatures there rose at a rate of 5 to 7 times the global average. Sea temperatures can be particularly harmful. to an annual limit. Mayer explains that an ice cube in warm water melts faster than ice that floats in cold water in a warm room.

Sea ice began to disappear exceptionally early this year in the Beaufort Sea, northern Canada and Alaska, the neighboring Chukchi Sea, and the Laptev Sea in Siberia — in part due to rising ocean temperatures.

The open ocean is blue in color and absorbs sunlight, further warming the Arctic. Sea ice reflects sunlight back into space, helping to keep the Arctic cool. Sharon Ginnop’s photo.
The main seas, straits and bays of the Arctic region. Image provided by the National Snow and Snow Data Center.

This fusion trend generated local feedback loops. Ice reflects at least 50% of solar radiation back into space. Labe explains that a blue, ice-free ocean absorbs about 90% of the sun’s heat, causing the sea to warm and melt more ice. Sea temperatures in August were among the hottest ever in the Beaufort Sea. A recent study stated that during 21Street Horn is a mile up from the North Pole Ocean water temperature has risen 2.3 times higher than the global average.

Ocean currents flowing to the North Pole from the south are also raising water temperatures. Warm influxes from the Bering Strait and the Pacific and Atlantic Oceans can delay fall refreezing or accelerate spring and summer ice loss.

Winds and storms also play a role in breaking up and spreading the ice. If the float is pushed into wide open water, it will likely melt. But on the northern coast of Greenland and along the Canadian archipelago where Arctic winds push the ice up against the ground, it’s accumulating, forming thick ice likely to withstand the warmth of summer.

Researchers compiled 19th century sea ice information using records from whaling ships, marine data and diaries. This data revealed weather fluctuations from year to year, which is what Labe calls “just a zigzag that goes up and down…until you hit the 80s, and then goes down.” He adds that the long-term trend “demonstrates a significant and clear change that is continuing in this region.”

The general downward trend At minimum Arctic sea ice extent from 1979 to 2022 12.6% per contract For the 1981 to 2010 average – about 30,300 square miles (78,500 square kilometers) per year, an area the size of Austria or South Carolina.

Changes in annual mean Arctic sea ice extent and volume over the satellite age (in red) compared to a reconstruction of Arctic sea ice extent dating back to the 19th century. Updated on 8/21/2022. picture Courtesy of Zachary Labe/Princeton/NOAA GFDL

On thin ice…

Since about 2005, the disappearance of Arctic sea ice – especially its lowest level in September – has dominated the news. There has been much less attention given to another important factor: the thickness of the ice, which has declined dramatically since the mid-1980s, Mayer says. At that time, multi-year ice covered nearly two-thirds of the Arctic seas. Today, about a third of the ice remains for several years.

Meyer reports that the oldest surviving ice many times melts and thickens during cold, gloomy winters, solid—perhaps 12 feet thick in some places, permanent—but it has virtually disappeared. “It now accounts for about 5% of the total ice cover, and holds primarily along the northern coast of Greenland and the Canadian Archipelago.”

Year one ice dominates now and is much thinner and more brittle, says Lapp, “So if you get extreme temperatures or big storm systems there, that ice is easy to break up and blow up and melt.”

He pointed to a unique and alarming event this year in the far north up to 88The tenth Parallel, only 185 miles from the North Pole. In the past, this was a year-round frozen area in thick ice packs. In recent years, satellite observations have revealed some patches of looser and less compacted ice, but this summer, “there have been large vents, up to 38 x 38 square miles, with very little, if any, ice,” he says. . “It was very cool, and indicates a smaller, thinner, more fractured ice cap.”

Labe’s analysis puts this in perspective. “The story is basically that there’s been thin ice almost every month across almost all of the Arctic for the past four decades.” Over the past 60 years, the thickness of sea ice has decreased by about six feet, or about 66%.

Sea surface temperatures (SSTs) in the Arctic and much of the North Atlantic and Pacific Oceans, as well as oceanic seas in the Northern Hemisphere on August 23, 2022. Extremely warm ocean conditions are found along parts of the Siberian coast, but are much colder than have been found Average conditions in the Bering Sea and the Norwegian Sea. Data and image courtesy of Climate Reanalyzer, University of Maine.

What begins at the North Pole…

Scientists say Earth’s climate system is interconnected, and the rapidly warming Arctic Ocean – the size of the 48 US states – is affecting the rest of the planet.

Several studies have indicated, for example, that the warming of the Arctic may alter the location and speed with which the atmospheric jet stream circulates around the northern hemisphere – Slugging deep south, or locking in place almost slowlyat times, which can contribute to shattering weather patterns and more severe weather. The polar vortexfor example, which have mostly orbited fast and narrow around the polar region in the past, are becoming more wobbly and unstable, sometimes dripping over the United States, Europe or Asia, blasting them with frigid hail.

Overall, Meyer says, “the Arctic response to greenhouse gases [in terms of sea ice] It is definitely a strong downtrend, and faster than the models expected. The Arctic is a completely different environment than it used to be, and this is very evident to anyone who lives or studies there [the polar region]. “

The extent of the ice in August from 1979 to 2022 shows a decrease of 10.1% per decade. Image provided by the National Snow and Snow Data Center.

There is constant guesswork about When will the Arctic Ocean see its first largely ice-free summer conditions. Early reports from the United Nations Intergovernmental Panel on Climate Change predicted that this could happen by 2100. These estimates are now so to the middle of the century, possibly by 2040.

This particular landmark event may be more important to the media than to scientists, says Lappé. “It is a symbol of climate science when we become ice-free. But we are already seeing impacts on the climate system, and the more ice we lose, the greater those impacts will be.”

The loss of sea ice, and the speed at which it occurs, “depends on the emissions trajectory we take over the next 10, 20, 30 years,” Meyer says. Human actions can make a positive difference.

Labe agrees. Climate models show that by reducing greenhouse gas emissions, we can reduce the chance of the Arctic being ice-free. I would note that climate models show that we are not locked into a snow-free future.”

Banner photo: The open ocean with some floating ice in August 2022 off Svarlbard in the Arctic. Sharon Ginnop’s photo.

A polar bear foraging in a semi-open ocean in the Arctic. Image credit: tim ellis on

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