3 Matching Annotations
  1. Feb 2021
  2. May 2017
    1. slope instability

      Slope instability occurs when mass-movement of rock, snow, or oil move downward due to gravity (Heritage). The types of slope instability are avalanches, landslides, rock fall, and rock slip, Slope instability can be detrimental depending on the infrastructure in that region. Water movement significantly contributes to slope instability. Water from snow or permafrost melt soaks into the soil, replacing air pockets and making the soil heavier (Nelson). Heavy soil on a steep slope can cause the soil to become dislodged and cause slope instability. The amount of water in the soil can also determine the slope angle. Too little water keeps the slope shallow, but some water can allow for a steeper slope due to changes in surface tension. Too much water caused a landslide because the excess water turns the soil into a fluid. Additional, unexpected permafrost melt can put too much water in the soil and lead to slope instability. Cold mountainous regions are often at risk for slope instability (Gruber). Permafrost exists in steep bedrock, which is categorized by a slope angle greater than 37 degrees. Ridges, spurs, and peaks are subject to increased permafrost melt that can lead to slope instability. Heat transfer by advection, or horizontal convection, is unpredictable and can occur through nearby ground water movement. This heat transfer leads to an increased rate of permafrost melt and can cause greater slope instability that heat transfer through the soil itself. Slope instability due to permafrost is directly influenced by climate change effects and could be detrimental to nearby populations and communities.

      References: "Slope Instability." Heritage-Newfoundland and Labrador. Accessed May 06, 2017. http://www.heritage.nf.ca/articles/environment/slope-instability.php.

      Nelson, Stephen A. "Slope Stability, Triggering Events, Mass Movement Hazards." Tulane EENS 3050. December 10, 2013. Accessed May 06, 2017. http://www.tulane.edu/~sanelson/Natural_Disasters/slopestability.htm.

      Gruber, S., and W. Haeberli. "Permafrost in steep bedrock slopes and its temperature-related destabilization following climate change." JOURNAL OF GEOPHYSICAL RESEARCH 112, no. F02S18 (June 8, 2007). http://onlinelibrary.wiley.com/store/10.1029/2006JF000547/asset/jgrf280.pdf;jsessionid=4ACF5A28370C79D8882CD5745BE13C0B.f02t03?v=1&t=j2dliru8&s=9d3e555adabe5cef09dd53635b4830823d3afa9d.

    2. 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.