In the summer of 2020, wildfires spread along the Arctic Circle, burning tundra and shrouding the whole of Siberia in smoke. By September 2020, Arctic fires had released nearly 250 megatons of carbon dioxide, about half of Australia's annual emissions from human activities and 2.5 times the record 2020 California wildfire season.
However, the fire was not extinguished, but turned underground and became a "zombie fire", which burned in the ice field for 8 months and is now back to light, and there have been about 70 "zombie fire" incidents in Alaska.
What is "zombie fires", the Arctic has the most peatlands on earth, and peat is made up of dead vegetation – moss, the remains of trees and shrubs, other Arctic plants – which do not completely decompose. Peat forms in wet and cold parts of the world, where organic matter degrades slowly. Peat reserves have been established for centuries or thousands of years; soils that are just a few feet deep may be thousands of years old. Today, peatlands cover about 4 million acres of the Arctic and store about 415 billion tons of carbon.
When peat dries out, it becomes a carbon-rich fuel that can be ignited with a single lightning strike. And the flame will penetrate deeper and deeper into the peat layer, slowly spreading throughout the area. In the end, it is like a time bomb, not knowing when it will ignite the vegetation above.
Studies have shown that usually the smouldering of peatlands is concentrated 10-30 cm below the surface, but scientists have also found smoldering of peatlands 50 cm or even deeper below the surface. This zombie fire can burn in peat and other organic matter for months or even years.
For the Arctic, zombie fires are like time bombs, and somehow they will cause a forest fire again.
These peatlands are of great importance to the global ecology, and are such an excellent insulator of frozen soil – so much so that since the Pleistocene, they have kept much of the Arctic subsurface frozen. Every semi-humus layer of about 1 centimeter thickness cools the permafrost layer below — frozen for two years or more — about 0.6°C.
Zombie fires burn underground, and the permafrost below melts and the ground becomes soft and collapsed. Trees rooted in this melted soil will tilt at all angles, and there will be many deep pits.
In addition, peat soils also store 30 to 40 percent of the carbon content of all soils on Earth. Zombie fires trigger wildfires, which release carbon dioxide and flammable methane; methane exacerbates fires in the Arctic, releases more greenhouse gases into the atmosphere, and ultimately triggers more severe warming and permafrost melting, more peat soil thaws, more wildfires, releases large amounts of carbon as well as flammable methane, and these wildfires go underground, turn into zombie fires, and begin a new cycle, in which as more soil thaws, the ice in the lower layers melts and loses, This makes it drier and easier to burn violently. This vicious circle has the potential to expand burned land areas, worsen the health of millions of people, and accelerate the pace of climate change as never before.
Scientists have found that in the first decade of the new millennium, the Arctic averaged 50 percent more fire areas per year than any ten years in the 1900s. Burn area continued to climb between 2010 and 2020, especially in Alaska, where 2015 was the second worst fire year on record and 2019 was another bad year. Scientists have found that the Arctic is now more frequent than the northern forests of about 3,000 years ago at any time since its formation, and may be higher than at any time in the past 10,000 years.
Professor Turesky warned, "The real bad news is that because of the presence of permafrost and peatlands, Arctic fires can penetrate the surface and penetrate thousands of years ago into old carbon layers." This carbon that was originally sealed was re-released, which is really terrible. ”
The most frightening thing is that these ice layers are also sealed with many ancient microorganisms, some species of frogs, toads and turtles can survive in extremely cold climates for months or even years, while bacteria, viruses, spores, and even some fungi can even survive in the ice for thousands of years, or even millions of years, and still maintain an active metabolism. And we need to know that in the process of formation of frozen soil, with the passage of time, more and more dead organisms are dying, and the sediments in the frozen soil are also accumulating, making the remains of previous organisms sink further. As a result, permafrost can reach depths of 1,000 to 1,600 meters, almost twice as much as the burj Khalifa in Dubai, the world's tallest building.
So the ice cap that covers the large surface of the earth is like Pandora's box, silently waiting to be opened. The terrible thing is that the box has been opened and some ancient microorganisms have been released. As the permafrost continues to melt, more and more ancient microorganisms will be released.
In 2016, in cold Siberia, a 12-year-old boy died of a mysterious illness. The disease then spread rapidly, infecting hundreds of people one after another, causing panic and chaos in the area. The culprit behind this deadly outbreak is a rare disease called anthrax, which was passed on to humans from infected reindeer, anthrax, which is released from the ice.
The ablation of permafrost can lead to the weight of many deadly pathogens that we once eliminated, causing outbreaks of deadly diseases such as plague or smallpox.
Prominent scientists Boris Revich and Marina Podonaja have predicted that one consequence of permafrost melting is the potential for deadly infectious vectors of the 18th and 19th centuries, especially near cemeteries where the victims of these infectious diseases were buried.