Climate Change in the Arctic. Permafrost is Not Necessarly Permanent.
The average temperature in much of Alaska and the Arctic regions of Canada, Russia, etc. is sufficiently low that part of the ground remains frozen year around.
Permafrost is defined as "subsurface earth materials whose temperature remains below 0°C continuously throughout two consecutive years."
Bare patches of permafrost.
Creative Commons Zero (CC0) image downloaded from Dreamstime.com
The top of this "permafrost" layer is typically a short distance under the earth's surface. It can extend downwards for hundreds of feet . It is widespread in the Arctic and boreal regions of the Northern Hemisphere. Permafrost underlies about 22% of the exposed land surface area of the Northern Hemisphere. 1
Permafrost generally contains immense amounts of carbon contained in organic matter. This is what remains of once-living plants, which -- while alive in the ancient past -- took in carbon from the atmosphere. They died, and then froze -- trapping the carbon inside. When the permafrost layer thaws, it releases carbon into the atmosphere in the form of gasses.
Zahra Hirji, writing for Inside Climate News, said:
"More than 40 percent of the world's permafrost ... is at risk of thawing, even if the world succeeds in limiting global warming to the international goal of 2 degrees Celsius." 4
This 2°C goal was established by the Paris Agreement and is now accepted by every country in the world with the exception of the U.S. President Donald Trump has declared global warming to be a Chinese government hoax, motivated by a desire to harm U.S. industry, and is disengaging the U.S. from the Paris Agreement.
Scientists believe that if all of the permafrost areas of the world were to defrost, it would eventually triple the level of carbon (C) in the atmosphere, in the form of Carbon Dioxide (CO2), Methane (CH4), and other gasses. That would greatly accellerate global climate change.
This thawing process generates a positive feedback loop:
Global warming thaws the permafrost,
CO2 and other gasses are released into the atmosphere,
That intensifies the greenhouse gasses there,
That causes increased global warming.
Return to Step 1, with a vengance.
Fortunately, it will take millenia to thaw-out all of the permafrost, even if the temperature rise goals of the Paris Agreement are not met. Also, even if all the permafrost is thawed, the greenhouse gasses will likely not cause a catastropic runaway temperature rise like what happened on the planet Venus -- the next planet from Earth towards the Sun. Its surface temperature is high enough to melt lead. However, it would make more parts of the Earth unliveable and cause more animal species to either migrate, die off, or both.
The term "greenhouse gasses" is used because they function like an actual greenhouse: They let sunlight through to the Earth but prevent heat from the Earth's surface from returing to outer space. Scientists have reached a concensus that CO2 and other greenhouse gases are the primary cause of climate change/global warming. Many religious conservatives, executives in the fossil fuel industries, and the politicians whose support the executives have purchased, disagree. Some believe that global warming is not happening. Others believe that it is real but is not caused by human activity, and thus cannot be prevented.
There are many greenhouse gasses in the atmosphere: Methane, Nitrous Oxide, Carbon Dioxide, etc. Of these, CO2 makes the greatest contribution to the greenhouse effect. Methane does not last as long as CO2 in the atmosphere as carbon dioxide does, However, it has a far greater heat-trapping ability and thus also is a major contribution to global warming.
The Arctic is warming about twice as fast as the rest of the planet. The abstract of an article in BioScience states:
"Global climate models project the strongest future warming in the high latitudes, with some models predicting a 7 to 8 degree Celsius (°C) warming over land in these regions by the end of the 21st century (IPCC 2007). As a consequence, thawing permafrost and the resulting microbial decomposition of previously frozen organic C[arbon] is one of the most significant potential feedbacks from terrestrial eco-systems to the atmosphere." 2
Max Holmes, a senior scientist and deputy director of Woods Hole Research Center said that thawing of the permafrost:
"... has all kinds of consequences both locally for this [Arctic] region, for the animals and the people who live here, as well as globally. It’s sobering to think of this magnificent landscape and how fundamentally it can change over a relatively short time period."
Dr. Vladimir E. Romanovsky, a permafrost researcher at the University of Alaska, Fairbanks, said that:
"At one northern site permafrost temperatures at shallow depths have climbed from minus 8 degrees Celsius to minus 3. Minus 3 is not that far from zero. If emissions and warming continue at the same rate, he said, near-surface temperatures will rise above freezing around the middle of the century." 3
(Minus 8 ºC is equivalent to 16 ºF; Minus 3 ºC is equivalent to 27 ºF; 0 ºC or 32 ºF is the freezing point of water.)
According to one recent estimate, the total carbon in the world's permafrost areas is believed to weigh about 1,672 billion metric tons. That is about 220 metric tonnes -- or 242 U.S. tons -- for every human on earth! 2
Dr. Sue Natali, a Woods Hole scientist and permafrost expert, said
"... one of the big questions to tackle -- what’s wet and dry now, and what will be wet and dry in the future. If the decomposing permafrost is wet, there will be less oxygen available to the microbes, so they will produce more methane. If the permafrost is dry, the decomposition will lead to more carbon dioxide."
Henry Fountain, writing in the New York Times, said:
"In addition to greenhouse gas emissions, thawing wreaks havoc on infrastructure, causing slumping of land when ice loses volume as it turns to water.
The thawing of permafrost is a gradual process. Ground is fully frozen in winter, and begins to thaw from the top down as air temperatures rise in spring. As average temperatures increase over years, this thawed, or active, layer can increase in depth." 3
An additional problem posed by melting of the permafrost is the release of mirobes that have been frozen there for tens of thousands of years. In 2016-AUG, an outbreak of anthrax in Siberia sickened 72 people and killed a 12-year-old. Health officials traced the infection to long-dormant antrax microbes in the corpses of ancient dead reindeer and other animals. There is a possibility of smallpox bacteria emerging somewhere in the future from the permafrost in the same way.
Jean-Michel Claverie, a genomics researcher who studies ancient viruses and bacteria, said:
"Permafrost is the place to preserve bacteria and viruses for hundreds of thousands — if not a million — years. It is dark, it is cold, and it is also without oxygen. ... There is no [ultraviolet] light. All the bacteria need is a thaw to wake back up. If you take a yogurt and put it in permafrost [that remains frozen], I’m sure in 10,000 years from now it still will be good to eat. ... We could actually catch a disease from a Neanderthal’s remains, which is amazing."
The following information sources were used to prepare and update the above
essay. The hyperlinks are not necessarily still active today.
T. Zhang, "Statistics and characteristics of permafrost and ground‐ice distribution in the Northern Hemisphere," Polar Geography Journal, Volume 23, 1999, Issue 2, at: http://www.tandfonline.com/
"Vulnerability of Permafrost Carbon to Climate Change: Implications for the Global Carbon Cycle," BioScience magazine, Vol 58, Issue 8, 2008-SEP, at: https://academic.oup.com/