PERMAFROST, the hidden climate risk

By Carlo Caloisi

Ice is certainly one of the first victims of climate change, although the effects of global warming are not limited to melting on the surface.

In the cold regions of the earth (particularly the Arctic, North America, and Siberia), much of the subsurface is frozen. To be classified as permafrost, it must have been frozen for at least two years (in many cases going back as far as the last ice age). It consists of frozen soil, rock, sediment, and the remains of vegetation and animals that froze before decomposition had its way. The thickness can vary from a few meters up to 1500 (Arctic regions).

Due to the warming effect it is melting, releasing into the atmosphere methane (CH4) and carbon dioxide (CO2) thus contributing to the increase of the greenhouse effect.

Not only that, but from recent studies by ESA-NASA (a collaboration between the European space agency and the entity responsible for aeronautics and aerospace activities of civil interest of the USA), the rapid thawing of permafrost in the Arctic could allow the release of radioactive waste from nuclear reactors and submarines of the Cold War englobed and potentially release antibiotic-resistant bacteria or unknown viruses. In this regard, in 2016 in Siberia, as a result of thawing from the permafrost of a reindeer, an anthrax virus was released that killed one child and infected many others so much so that Russian military units specializing in biological warfare intervened.

Considering that it covers 25% of the northern hemisphere and that scientists estimate it contains almost twice the amount of carbon than that present in the atmosphere, a large-scale melting could trigger a feedback loop with serious climatic consequences.

The first effects are already appearing, causing immediate effects to the citizens living in those areas.

In Siberia, in the cities of Chapuchai and Yakutsk and in some regions of China, the thawing of permafrost is causing the collapse of houses, the subsidence of roads and the collapse of infrastructure such as airports and pipelines that could cause environmental disasters due to oil spills. Similar facts have also happened in the Norwegian islands of Svalbard where, due to subsidence phenomena, thousands of houses have been demolished.

Considering the significance of the melting that would have repercussions, albeit to a lesser extent, even on the sea level, to better understand the behavior and the effects on climate, researchers and scientists have organized themselves by creating, among others (CALM-Circumartic Active Layer Monitoring, IPA-International Permafrost Association, IGU-International Geographic Union, etc.. .), the “Global Terrestrial Network for Permafrost” (GTN-P), which has the task of managing a global network of observations and measurements (thermal state, thickness of the active and deep layer, etc. . .) collecting them in a database available to the entire scientific community or as in the case of the “ESA-NASA Arctic Methane and Permafrost Challenge” (ESA-European Space Agency; NASA-National Aeronautics and Space Administration) that, with a common operation are monitoring, through satellite observations, the current methane emissions in the Arctic as a function of the volumes of dissolved permafrost.


Over the years the European Union, which has included in the context of global warming permafrost in the funding of the European Green Deal, has directly supported some studies aimed at better understanding the problem, first with the project “Changing permafrost in the Arctic and its global effects in the 21st century” ended in 2015 and then with CC-Top (Cryosphere-Carbon on Top of the Earth) concluded in 2021 through which several articles have been published on the most prestigious journals such as “Nature”, “Science” and “PNAS”.

The project’s studies of past periods of rapid warming have confirmed the correspondence between large permafrost carbon releases and rapid increases in atmospheric CO2.

In addition, they have provided new insights into submarine permafrost, particularly that it has reached the thaw point at the shallow ocean and that melting has increased tenfold in recent decades compared to the rate of terrestrial melting.

Carlo Caloisi


  1. Permafrost: what it is and the risks related to melting (Alfred Wegener Institut): ;
  2. Satellites yield insight into not so permanent permafrost (ESA, maggio 2019): ;
  3. Long-term permafrost record details Arctic thaw (ESA, dicembre 2020): ;
  4. Permafrost thaw could release bacteria and viruses (ESA, ottobre 2021): ;
  5. Satellites pinpoint communities at risk of permafrost thaw (ESA, novembre 2021): ;
  6. Permafrost thaw: it’s complicated (ESA, gennaio 2022): ;
  7. Permafrost dynamics and the risk of anthrax transmission: a modelling study (Nature, ottobre 2020):
  8. Impacts on permafrost degradation on infrastrutures (Nature reviews earth and environment – gennaio 2022): ;
  9. As permafrost thaws around the world, the steel, concrete and tarmac structures sitting on top are warping and crumbling. Is there anything engineers can do to adapt?: ;
  10. Scientists say vast areas of Siberia are thawing with “devastating consequences” – BBC News: ;
  11. Russia facing $97bn bill as melting permafrost collapses buildings: ;
  12. Alien landscapes and collapsing homes as Siberia’s permafrost thaws (France 24 – inglese): ;
  13. Global Terrestrial network for Permafrost (GTN-P): ;
  14. ESA-NASA – Arctic Methane and Permafrost Challenge (AMPAC):  ;
  15. Changing Permafrost in the Arctic and its Global Effects in the 21st Century: ;
  16. Cryosphere-Carbon on Top of the Earth (CC-Top): Decreasing Uncertainties of Thawing Permafrost and Collapsing Methane Hydrates in the Arctic: ;
  17. A stronger EU engagement for a peaceful, sustainable and prosperous Arctic (ottobre 2021):  .

IMAGES (in sequential order):

  1. Permafrost in Teshekpuk, Alaska:;
  2. The layers of permafrost: ;
  3. Permafrost in Itkillik River in northern Alaska:


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