The following is a re-post of my Reply #1054 in the Conservative Scientists & its Consequences thread in the Consequences folder:
The linked open access reference examines the coastal dynamics and creation of new submarine permafrost in shallow water of the central Laptev Sea (see the first attached image) and concludes: "For this region, it can be summarized that recent increases in coastal erosion rate and longer-term changes to benthic temperature and salinity regimes are expected to affect the depth to submarine permafrost, leading to coastal regions with shallower IBP." (see the second attached image), where IBP means: ice-bonded permafrost.
This research and conclusions may have profound implications if the abrupt collapse of the West Antarctic Ice Sheet, WAIS, in the next few decades leads to rapid increase in sea level in the Arctic Sea. This is because more prior researchers have assumed that the IBP would be covered by a layer of somewhat protective non-ice-bonded sediment. However, as Overduin (2015) make clear, wave driven coastal erosion (which will increase if/when the Arctic Sea Ice extent seasonally collapses) can/will expose the previously buried but new submarine IBP to relatively rapid warming from the sea water; which would likely result in a multi-decadal period (starting with the ASLR possibly around 2050) of relatively rapid methane emissions as the associated methane hydrates in the new submarine permafrost region decompose:
Overduin, P., Wetterich, S., Günther, F., Grigoriev, M. N., Grosse, G., Schirrmeister, L., Hubberten, H.-W., and Makarov, A.: Coastal dynamics and submarine permafrost in shallow water of the central Laptev Sea, East Siberia, The Cryosphere Discuss., 9, 3741-3775, doi:10.5194/tcd-9-3741-2015, 2015.
http://www.the-cryosphere-discuss.net/9/3741/2015/tcd-9-3741-2015.htmlhttp://www.the-cryosphere-discuss.net/9/3741/2015/tcd-9-3741-2015.pdfAbstract: "Coastal erosion and relative sea-level rise transform terrestrial landscapes into marine environments. In the Arctic, these processes inundate terrestrial permafrost with seawater and create submarine permafrost. Permafrost begins to warm under marine conditions, which can destabilize the sea floor and may release greenhouse gases. We report on the transition of terrestrial to submarine permafrost at a site where the timing of inundation can be inferred from the rate of coastline retreat. On Muostakh Island in the central Laptev Sea, East Siberia, changes in annual coastline position have been measured for decades and vary highly spatially. We hypothesize that these rates are inversely related to the inclination of the upper surface of submarine ice-bonded permafrost (IBP) based on the consequent duration of inundation with increasing distance from the shoreline. We compared rapidly eroding and stable coastal sections of Muostakh Island and find permafrost-table inclinations, determined using direct current resistivity, of 1 and 5 %, respectively. Determinations of submarine IBP depth from a drilling transect in the early 1980s were compared to resistivity profiles from 2011. Based on boreholes drilled in 1982–1983, the thickness of unfrozen sediment overlying the IBP increased from 0 up to 14 m below sea level with increasing distance from the shoreline. The geoelectrical profiles showed thickening of the unfrozen sediment overlying ice-bonded permafrost over the 28 years since drilling took place. Parts of our geoelectrical profiles trace permafrost flooded, and showed that IBP degradation rates decreased from over 0.6 m a−1 following inundation to around 0.1 m a−1 as the duration of inundation increased to 250 years. We discuss that long-term rates are expected to be less than these values, as the depth to the IBP increases and thermal and pore water solute concentration gradients over depth decrease. For this region, it can be summarized that recent increases in coastal erosion rate and longer-term changes to benthic temperature and salinity regimes are expected to affect the depth to submarine permafrost, leading to coastal regions with shallower IBP."