Accelerating Thermokarst Transforms Ice‐Cored Terrain Triggering a Downstream Cascade to the Ocean

Recent climate warming has activated the melt‐out of relict massive ice in permafrost‐preserved moraines throughout the western Canadian Arctic. This ice that has persisted since the last glaciation, buried beneath as little as 1 m of overburden, is now undergoing accelerated permafrost degradation...

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Bibliographic Details
Published in:Geophysical research letters 2017-11, Vol.44 (21), p.11,080-11,087
Main Authors: Rudy, A. C. A., Lamoureux, S. F., Kokelj, S. V., Smith, I. R., England, J. H.
Format: Article
Language:English
Subjects:
Climate change
Deglaciation
downstream impacts
Fluvial transport
Glaciation
Glaciology
Global warming
Ground ice
Hydrologic regime
Hydrology
Ice
ice‐cored terrain
Landscape
Meltwater
Moraines
Oceans
Permafrost
Polar environments
Runoff
Sediments
Solutes
Summer
Terrestrial environments
Thermokarst
water quality
western Canadian Arctic
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Summary:Recent climate warming has activated the melt‐out of relict massive ice in permafrost‐preserved moraines throughout the western Canadian Arctic. This ice that has persisted since the last glaciation, buried beneath as little as 1 m of overburden, is now undergoing accelerated permafrost degradation and thermokarst. Here we document recent and intensifying thermokarst activity on eastern Banks Island that has increased the fluvial transport of sediments and solutes to the ocean. Isotopic evidence demonstrates that a major contribution to discharge is melt of relict ground ice, resulting in a significant hydrological input from thermokarst augmenting summer runoff. Accelerated thermokarst is transforming the landscape and the summer hydrological regime and altering the timing of terrestrial to marine and lacustrine transfers over significant areas of the western Canadian Arctic. The intensity of the landscape changes demonstrates that regions of cold, continuous permafrost are undergoing irreversible alteration, unprecedented since deglaciation (~13 cal kyr B.P.). Key Points Accelerated thermokarst significantly increases the sediment and solute transport downstream to both lacustrine and coastal environments Melt of relict ground ice is a major contribution to discharge augmenting summer runoff Regions of cold, continuous permafrost are undergoing irreversible alteration, unprecedented since ~13 cal kyr B.P.
ISSN:0094-8276
1944-8007
DOI:10.1002/2017GL074912