Publication Date:
2024-04-19
Description:
Infrastructure built on perennially frozen ice-rich ground relies heavily on thermally stable subsurface conditions. Climate-warming-induced deepening of ground thaw puts such infrastructure at risk of failure. For better assessing the risk of large-scale future damage to Arctic infrastructure, improved strategies for model-based approaches are urgently needed.
We used the laterally coupled 1D heat conduction model CryoGrid3 to simulate permafrost degradation affected by
linear infrastructure.We present a case study of a gravel road built on continuous permafrost (Dalton highway, Alaska) and
forced our model under historical and strong future warming conditions (following the RCP8.5 scenario). As expected, the
presence of a gravel road in the model leads to higher net heat flux entering the ground compared to a reference run
without infrastructure and thus a higher rate of thaw. Further, our results suggest that road failure is likely a consequence
of lateral destabilisation due to talik formation in the ground beside the road rather than a direct consequence of
a top-down thawing and deepening of the active layer below the road centre. In line with previous studies, we identify enhanced
snow accumulation and ponding (both a consequence of infrastructure presence) as key factors for increased soil
temperatures and road degradation. Using differing horizontal model resolutions we show that it is possible to capture
these key factors and their impact on thawing dynamics with a low number of lateral model units, underlining the potential
of our model approach for use in pan-Arctic risk assessments.
Our results suggest a general two-phase behaviour of permafrost degradation: an initial phase of slow and gradual
thaw, followed by a strong increase in thawing rates after the exceedance of a critical ground warming. The timing
of this transition and the magnitude of thaw rate acceleration differ strongly between undisturbed tundra and
infrastructure-affected permafrost ground. Our model results suggest that current model-based approaches which do not
explicitly take into account infrastructure in their designs are likely to strongly underestimate the timing of future Arctic
infrastructure failure.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
,
isiRev
Format:
application/pdf
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