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| Autores principales: | , |
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| Formato: | Recurso digital |
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| Publicado: |
Zenodo
2025
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| Acceso en línea: | https://doi.org/10.5281/zenodo.17729561 |
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- Permafrost, ground that remains frozen for at least two consecutive years, underlies approximately a quarter of the Northern Hemisphere land area and contains vast reservoirs of organic carbon, equivalent to twice the amount currently in the atmosphere. Historically considered a stable component of the cryosphere, permafrost is now experiencing accelerated thaw due to anthropogenic climate change, transforming landscapes and releasing greenhouse gases. This paper posits that permafrost thaw is not merely a regional environmental concern but represents a planetary geomorphic tipping point, capable of initiating irreversible changes with global ramifications. We review the mechanisms driving permafrost degradation, including thermal disturbances leading to active layer deepening and physical disturbances manifesting as mass movements and coastal erosion. The geomorphic manifestations, such as thermokarst development, landscape collapse, and hydrological shifts from nival to pluvial dominance, are profoundly altering Arctic and sub-Arctic environments. Crucially, the release of stored organic carbon as carbon dioxide and methane constitutes a powerful positive feedback loop, amplifying global warming and accelerating further thaw. Furthermore, the increasing flux of dissolved and particulate organic matter from terrestrial to aquatic ecosystems in the Arctic Ocean alters marine biogeochemistry and its capacity to receive and export risk to the global system. This paper synthesizes current understanding of these interconnected processes, highlighting how local-scale permafrost degradation scales up to a systemic, non-linear change with the potential to trigger cascading impacts across Earth's climate and biogeochemical systems. The discussion emphasizes the urgency of recognizing permafrost thaw as a critical threshold in Earth system dynamics, necessitating immediate and comprehensive climate action to mitigate its most severe consequences.