Louise M. Farquharson et al. (ice and climatology scientists) on rapid melting of Arctic permafrost (2019): “Climate warming in regions of ice‐rich permafrost can result in widespread thermokarst development, which reconfigures the landscape and damages infrastructure. We present multi‐site time‐series observations which couple ground temperature measurements with thermokarst development in a region of very cold permafrost. In the Canadian High Arctic between 2003 and 2016, a series of anomalously warm summers caused mean thawing indices to be 150 – 240 % above the 1979‐2000 normal resulting in up to 90 cm of subsidence over the 12‐year observation period. Our data illustrate that despite low mean annual ground temperatures, very cold permafrost (<‐10°C) with massive ground ice close to the surface is highly vulnerable to rapid permafrost degradation and thermokarst development. We suggest that this is due to little thermal buffering from soil organic layers and near surface vegetation, and the presence of near surface ground ice. Observed maximum thaw depths at our sites are already exceeding those projected to occur by 2090 under RCP 4.5.
Key Points. Observed thermokarst development in very cold permafrost at 3 monitoring sites along a 700 km transect in the Canadian High Arctic. Rapid landscape response to above average summer warmth is due to limited thermal buffering from overlying ecosystem components and near‐surface ground ice. Change was greatest at Mould Bay where thawing index values were 240 % above historic normals causing ~90 cm of subsidence in 12 years” (Louise M. Farquharson, Vladimir E. Romanovsky, William L. Cable, Donald A. Walker , Steven Kokelj, Dimitry Nicolsky, “Climate change drives widespread and rapid thermokarst development in very cold permafrost in the Canadian High Arctic ”, Geophysical Research Letters, 10 June 2019: https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019GL082187 ).
Louise Farquharson (researcher at the Permafrost Laboratory at the University of Alaska Fairbanks) on rapid permafrost melting (2019): “This change is unprecedented on this kind of time scale. I was very surprising to just see how rapidly the landscape changed. We started monitoring these sites back in the early 2000s and this landscape surrounding each of our stations was fairly flat. It was fairly easy to walk across the area. It’s pretty amazing. There are these troughs of up to 90 centimeters (about 35 inches). It’s kind of like the elevation of a kitchen countertop. There are small ponds in many of these troughs. It’s quite a profound change. Locally, these changes, they affect the vegetation, the ecology, the hydrology. It’s kind of a canary in the coal mine situation I would say” (Louise Farquharson quoted in Jane Wesner Childs, “Arctic permafrost melting 70 years sooner than expected”, Countercurrents, 18 June 2019: https://countercurrents.org/2019/06/arctic-permafrost-melting-70-years-sooner-than-expected ; Jane Wesner Childs, “Arctic permafrost melting 70 years sooner than expected, study finds”, Earth First ! Newswire, 17 June 2019: https://earthfirstjournal.org/newswire/2019/06/17/arctic-permafrost-melting-70-years-sooner-than-expected-study-finds/ ).