Lecture Summary
Today's lecture focused on Permafrost, its characteristics, distribution, and implications of its thaw due to global warming. We discussed the components of permafrost, the processes affected by its thaw, and the global consequences. Furthermore, efforts to monitor and study permafrost changes were also detailed.
Key Points from the Lecture
Definition and Composition of Permafrost
- Permafrost refers to ground that remains continuously frozen for at least two consecutive years.
- Consists of rock, sediment, or soil with varying amounts of ice that binds the material together like cement.
Distribution
- Found in cold climates of high latitudes and alpine regions.
- Extends up to 25% of the Northern Hemisphere's terrestrial surface.
- Located extensively in regions like Russia, Canada, Alaska, China, Greenland, Scandinavia, and only on Zugspitze in Germany.
Thawing of Permafrost
- Rising global temperatures are causing the permafrost to thaw, which poses serious structural and ecological risks.
- Thawing permafrost leads to weaker and more unstable ground as the ice that binds sediments melts.
Implications of Thawing
- Environmental Impact
- Release of greenhouse gases (CO2 and methane) from organic materials stored in permafrost, enhancing global warming.
- Introduction of carbon into the atmosphere through microbial digestion of thawed organic material.
- Physical and Economic Damage
- Damage to infrastructure built on permafrost due to ground subsidence and shifts.
- Increased risks of landslides and rockfalls in mountainous areas.
- Coastal erosion due to rising water temperatures and severe storms.
- Ecological Consequences
- Disappearance of lakes and wetlands as thawing permafrost allows water to seep through the soil more readily.
Permafrost Monitoring and Research Initiatives
- Global Terrestrial Network for Permafrost (GTNP)
- Coordinates permafrost temperature measurements and active layer monitoring.
- Circular Active Layer Monitoring (CALM)
- Gathers data on the thickness of the active layer above permafrost.
- Data collected is shared globally to help researchers understand the extent and behavior of permafrost changes.
Conclusion
- Permafrost is proving to be not as permanent as previously thought, emphasizing the need for international cooperation to tackle the implications of its change due to climate warming.