Speaking: Charles "Chuck" Abolt, Los Alamos National Lab
One of the most conspicuous signals of climate change in high-latitude tundra is the expansion of thermokarst pools above melting ice wedges. Beyond expressing permafrost degradation, this process exerts strong feedbacks on subsequent thaw rates through a series of positive and negative feedbacks which play out over timespans of decades. In this study, we assessed circumpolar thermokarst pool expansion from 2008-present at twenty-seven survey areas dispersed throughout the Arctic. Our workflow, based on convolutional neural networks and executed on a single GPU, segmented thermokarst pools from submeter-resolution panchromatic imagery from the WorldView satellites. The results revealed that recent circumpolar pool expansion has been uneven but widespread, including in very cold settings. Among other findings, the observations indicate that topography plays a significant role in determining ice wedge vulnerability to climate change, as pool expansion was often concentrated in convex regions within upland landscapes.