Apr 2, 2019

Extremes of summer climate trigger thousands of thermokarst landslides in a High Arctic environment

by
Antoni G. Lewkowicz, Robert G. Way
,
Nature Communications
  • States that retrogressive thaw slumps (RTS) – landslides caused by the melt of ground ice in permafrost – have become more common in the Arctic, but the timing of this recent increase and its links to climate have not been fully established
  • Annually resolves RTS formation and longevity for Banks Island, Canada (70,000 km2) using the Google Earth Engine Timelapse dataset
  • Describes a 60-fold increase in numbers between 1984 and 2015 as more than 4000 RTS were initiated, primarily following four particularly warm summers
  • Finds that color change due to increased turbidity occurred in 288 lakes affected by RTS outflows and sediment accumulated in many valley floors
  • Modeled RTS initiation rates increased by an order of magnitude between 1906–1985 and 2006–2015, and are projected under RCP4.5 to rise to >10,000 decade−1 after 2075
  • These results provide additional evidence that ice-rich continuous permafrost terrain can be highly vulnerable to changing summer climate