Permafrost, or permanently frozen ground, is the subsoil (soil, sediment, or rock) that remains frozen for at least two consecutive years. Permafrost occurs mainly in polar regions in the Northern Hemisphere, such as Siberia, Alaska, Canada, and some parts of Greenland, but also in high-altitude areas.

❄️ Main characteristics of permafrost

• Extension: It covers approximately 24 % of the Earth's surface in the Northern Hemisphere.
• Thickness: It can range from a few meters to more than 1,500 meters in the coldest areas of Siberia.
• Active layer: The surface layer of permafrost that thaws in summer and freezes again in winter. Its thickness ranges from 0.3 to 4 meters.

🌡️ The importance of permafrost in the context of climate change

Permafrost is of fundamental importance to the global climate system and its melting has significant consequences:

• 💨 Storing huge amounts of carbon
  • Organic matter reservoir: Permafrost contains approximately 1,500 billion tons of carbon, almost double the amount of carbon currently present in the atmosphere.
  • This carbon comes from incompletely decomposed plant and animal remains that have accumulated over millennia.
• 🌫️ Greenhouse gas emissions during heating
  • Carbon dioxide (CO₂) and methane (CH₄): As permafrost thaws, microorganisms begin to break down organic matter, leading to the release of CO₂ and methane.
  • Methane is particularly significant because it is approximately 25 times more effective at trapping heat than CO₂ over a 100-year timescale.
• 🔥 Strengthening climate change
  The release of these gases creates a positive feedback loop that can accelerate global warming.

🏚️ Impacts on infrastructure and the environment

• Soil instability: Melting permafrost is causing landslides and terrain collapse, threatening buildings, roads and other infrastructure projects in Arctic regions.
• Hydrological changes: Changes in water runoff can affect local ecosystems, such as the formation of new lakes or the drying up of wetlands.
• 🦠 Releasing ancient pathogens: There is concern that melting permafrost could release long-preserved viruses and bacteria, as happened in 2016 in Russia with anthrax.

🌍 Impact on global climate

• ⚡ Amplification of extreme events: Increased greenhouse gas emissions may contribute to more frequent and intense extreme weather events.

🔭 Current observations and forecasts

• Faster Arctic warming: The Arctic is warming twice as fast as the rest of the world, accelerating the melting of permafrost.
• 💥 Potential carbon emissions: It is estimated that by 2100, 120 to 240 billion tons of carbon could be released from melting permafrost if current emissions trends continue.
• Uncertainty in scientific models: Melting permafrost poses a major uncertainty in climate models because the exact extent and rate of carbon release are difficult to predict.

🔬 Measures and research

• 🛰️ Permafrost monitoring: Scientific teams use satellite observations, soil probes, and models to track changes in permafrost.
• 🌿 Reducing emissions: Global efforts to reduce greenhouse gas emissions are key to slowing warming and protecting permafrost.
• 🏗️ Infrastructure adaptation: Development of new construction techniques and materials for Arctic regions that take into account changing soil conditions.

Permafrost plays a critical role in the global climate system as a vast carbon reservoir. Its melting due to rising global temperatures could significantly contribute to increased greenhouse gas emissions, creating a dangerous feedback loop accelerating climate change. In addition, melting permafrost has significant impacts on local communities, infrastructure and ecosystems. Therefore, continued research, monitoring and global efforts to reduce emissions are essential to minimize these risks and protect permafrost for future generations. Spring