Home Ice bergs What is arctic amplification? Definition, causes and environmental implications

What is arctic amplification? Definition, causes and environmental implications

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The amplification of the Arctic is the increasingly accelerated warming occurring in the region of the world north of latitude 67ON. For more than four decades, temperatures in the Arctic have risen two to three times the rate in the rest of the world. High temperatures melt snow covers and glaciers. The permafrost is melting and collapsing. The pack ice is disappearing.

Unfortunately, some or all of these effects of heat trigger further increases in temperature. The effect becomes a cause, which becomes a greater effect, which becomes a stronger cause. Arctic amplification is an accelerated feedback loop that is accelerating climate change in the rest of the world.

The causes and mechanisms of arctic amplification

While scientists generally agree that the Arctic has warmed faster than the rest of the world, there is still debate as to why. The almost universal best guess, however, is that greenhouse gases are to blame.

How does Arctic amplification begin?

Greenhouse gases like carbon dioxide (CO2) and methane (CH4) allow the sun’s rays to heat up through the atmosphere. A warmed Earth reflects heat back to space. However, CO2 only allows about half of the thermal energy radiating skyward from Earth to escape from the troposphere (Earth’s lowest atmospheric layer) into the stratosphere (the next layer) and finally in space. According to the United States Environmental Protection Agency (EPA), CH4 is about 25 times more effective than CO2 at trapping heat.

Together with the sun’s rays, the heat trapped by greenhouse gases further warms the polar air and thaws large areas of the Arctic. It is during the thaw that arctic amplification comes into play. It emits more greenhouse gases into the air, which causes more thaw. Which puts even more greenhouse gases in the air. This causes even more thawing. Which puts ….

Melting sea ice and amplification of the Arctic


Winter top-down aerial view of cracked ice on the Baltic Sea around Helsinki.
Miemo Penttinen – miemo.net / Getty Images

New research from a team of scientists from the State University of New York in Albany and the Chinese Academy of Sciences in Beijing suggests melting sea ice is the most responsible factor in accelerating warming of the Arctic.

According to the investigation team, the white color of the pack ice helps the ice stay frozen. It does this by reflecting about 80% of the sun’s rays away from the ocean. Once the ice melts, however, it leaves more and more vast expanses of blackish-green ocean exposed to sunlight. These dark colored areas absorb rays and retain heat. This melts extra ice from the bottom, exposing more dark water that will absorb heat from the sun, melting more ice, and so on.

Thawing permafrost also contributes to arctic amplification

Permafrost is frozen ground made up largely of rotten plants. It is full of carbon because, as part of the photosynthetic process, living plants continuously extract CO2 from the air.


In the subarctic tundra of the Blackstone Highlands, melting permafrost ice is exposed along the Dempster Gravel Road and the Ogilvie Mountains in Tombstone Territorial Park in the Yukon Territory.
milehightraveler / Getty Images

Carbon

Scientists once believed that the carbon in permafrost binds tightly to iron and is therefore safely sequestered from the atmosphere. However, in a study published in the peer-reviewed journal Nature Communication, a team of international scientists shows that iron does not trap CO2 permanently. This is because as the permafrost melts, the bacteria frozen inside the soil become active. They use iron as a source of food. When they consume it, previously trapped carbon is released. In a process called photomineralization, sunlight oxidizes the released carbon to CO2. (To paraphrase a biblical phrase: “From CO2, carbon has come, and to CO2 it must come back.”)

Added to the atmosphere, CO2 helps existing CO2 melt snow, glaciers, permafrost and more sea ice.

The international team of scientists recognizes that they do not yet know how much CO2 is released into the atmosphere when permafrost melts. Despite this, they estimate that the amount of carbon contained in permafrost is four times the total amount of CO2 emitted by human activities since the industrial revolution.

Methane

Meanwhile, CH4 is the second most common greenhouse gas. It too is frozen in the permafrost. According to the EPA, CH4 is about 25 times more powerful than CO2 at trapping heat in the Earth’s lower atmosphere.

Forest fires and arctic amplification

As temperatures rise and permafrost thaws and dries up, prairies become powder kegs. When they burn, the CO2 and CH4 in the vegetation ignite. Suspended in the air in smoke, they add to the greenhouse gas load of the atmosphere.

Nature.com reports that the Russian forest fire remote monitoring system identified 18,591 distinct arctic forest fires in Russia in the summer of 2020; over 35 million acres burned. The Economist reported that in June, July and August 2019, 173 tons of carbon dioxide were released into the atmosphere from arctic forest fires.

Current and expected climatic consequences beyond the Arctic Circle of Arctic amplification

With a new arctic climate setting in, higher temperatures and extreme weather events radiate towards the Earth’s mid-latitudes.


Huge icebergs floating in the Arctic Ocean, in Ilulissat, Greenland, a Unesco World Heritage Site.
Monica Bertolazzi / Getty Images

The jet stream

As the National Oceanic and Atmospheric Administration (NOAA) explains, jet streams are particularly rapid air currents. They are like rivers of strong wind in the “tropopause”, which is the border between the troposphere and the stratosphere.

Like any wind, they are formed by differences in air temperature. When the ascending equatorial air and the descending cold polar air intersect, they create the current. The greater the temperature difference, the faster the jet stream. Due to the direction in which the Earth turns, the jet streams move from west to east, although the flow can also temporarily move from north to south. It can temporarily slow down and even reverse. Jet streams create and push the weather.

The air temperature differences between the poles and the equator decrease, which means the jets weaken and meander. This can cause unusual weather conditions as well as extreme weather events. Weaker jets can also cause heat waves and cold waves to linger in one place longer than usual.

The polar vortex

In the stratosphere of the Arctic Circle, cold air currents swirl counterclockwise. Many studies show that warming temperatures are disrupting this vortex. The resulting mess further slows the jet stream. In winter, this can create heavy snow and extreme cold spells in mid-latitudes.

And Antarctica?

According to NOAA, Antarctica is not warming as quickly as the Arctic. Many reasons have been put forward. One is that the winds and weather conditions of the ocean around it can have a protective function.

The winds in the seas surrounding Antarctica are among the fastest in the world. According to the United States National Ocean Service, during the “age of the sail” (15th to 19th centuries), sailors named the winds after lines of latitude near the southern tip of the world and recounted stories of wild rides courtesy of “Roaring Forties”, “Furious Fifty” and “Screaming Sixties”.

These strong winds can deflect hot air jets from Antarctica. Despite everything, Antarctica is heating up. NOAA reports that between 2002 and 2020, Antarctica lost an average of 149 billion tonnes of ice per year.

Some environmental implications of arctic amplification

Arctic amplification is expected to increase over the next decades. NOAA notes that “the 12-month period from October 2019 to September 2020 was the second warmest year on record for surface air temperatures over arctic lands.” The temperature extremes for that year were the continuation of a “seven-year streak of the warmest temperatures on record since at least 1900”.

NOAA also reports that as of September 15, 2020, the area of ​​the Arctic Circle covered by sea ice was only 1.44 million square miles, the smallest extent in the 40-year history of the outfit. satellite recordings.

Meanwhile, a 2019 study led by John Mioduszewski of the Arctic Hydroclimatology Research Laboratory at Rutgers University and published in the peer-reviewed journal The Cyrosphere, suggests that by the end of the 21st century the Arctic will be almost ice-free.

None of this bodes well for planet Earth.