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Threshold sensitivity of shallow Arctic lakes and sublake permafrost to changing winter climate

Geophysical Research Letters
By: , , , , , , and 
https://doi.org/10.1002/2016GL068506

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Abstract

Interactions and feedbacks between abundant surface waters and permafrost fundamentally shape lowland Arctic landscapes. Sublake permafrost is maintained when the maximum ice thickness (MIT) exceeds lake depth and mean annual bed temperatures (MABTs) remain below freezing. However, declining MIT since the 1970s is likely causing talik development below shallow lakes. Here we show high-temperature sensitivity to winter ice growth at the water-sediment interface of shallow lakes based on year-round lake sensor data. Empirical model experiments suggest that shallow (1 m depth) lakes have warmed substantially over the last 30 years (2.4°C), with MABT above freezing 5 of the last 7 years. This is in comparison to slower rates of warming in deeper (3 m) lakes (0.9°C), with already well-developed taliks. Our findings indicate that permafrost below shallow lakes has already begun crossing a critical thawing threshold approximately 70 years prior to predicted terrestrial permafrost thaw in northern Alaska.

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Publication type Article
Publication Subtype Journal Article
Title Threshold sensitivity of shallow Arctic lakes and sublake permafrost to changing winter climate
Series title Geophysical Research Letters
DOI 10.1002/2016GL068506
Volume 43
Issue 12
Year Published 2016
Language English
Publisher American Geophysical Union
Contributing office(s) Alaska Science Center Geography
Description 8 p.
First page 6358
Last page 6365
Country United States
State Alaska
Other Geospatial Teshekpuk Lake, Umiat Lake
Online Only (Y/N) N
Additional Online Files (Y/N) N
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