- May 2017
thermal degradation of the permafrost
Thermal degradation is the process of the breaking of molecules due to heating (Zeus). In Arctic regions, thermal degradation can occur to permafrost. This can lead to uneven snowmelt and ground instability (Grandpre). The ground instability affects any infrastructure built on permafrost, including roads, buildings, or piping systems. Uneven melting of the permafrost can create holes or indentations in roadways. A study by the Canadian Journal of Earth Sciences in 2011 showed that heat transfer from groundwater movement can increase the rate of thermal degradation of permafrost. In areas where wildfires are prevalent, thermal degradation of permafrost is an even greater issue (Jafarov). Climate change effects change the patterns and prevalence of forest fires. A study performed for Environmental Research Letters found that under conditions of severe fire in an upland forest where no other climate change effects are present, 18 meters of permafrost can degrade in 120 years. In lowland forests, permafrost is more resilient to thermal degradation and these effects were not found. Wildfires affect permafrost because they burn the organic layer of soil and the rate of permafrost melt is directly impacted by how much of the organic layer is burned. If a thick organic soil layer is present and the fire is short-lived, the permafrost may not melt. Climate change also increases the rate of thermal degradation in permafrost. Temperatures in northern high latitude regions are expected to rise by 2.5 to 7 degrees Celsius. The thermal degradation of permafrost is important not only due to increased carbon emissions in the air and oceans, but also for its negative effects of infrastructure.
References: Grandpré, Isabelle De, Daniel Fortier, and Eva Stephani. "Degradation of permafrost beneath a road embankment enhanced by heat advected in groundwater." Canadian Journal of Earth Sciences. August 01, 2012. Accessed May 06, 2017. http://cjes.geoscienceworld.org/content/49/8/953.
Jafarov, E. E., V. E. Romanovsky, H. Genet, A. D. McGuire, and S. S. Marchenko. "The effects of fire on the thermal stability of permafrost in lowland and upland black spruce forests of interior Alaska in a changing climate." Environmental Research Letters 8, no. 3 (August 27, 2013). Accessed May 06, 2017. http://iopscience.iop.org/article/10.1088/1748-9326/8/3/035030/pdf.
"Thermal Degradation of Plastics." Zeus Industrial Products Inc. 2005. Accessed May 06, 2017.