Title: Drying of tundra landscapes will limit subsidence-induced acceleration of permafrost thaw

Abstract

We used a model for permafrost hydrology informed by detailed measurements of soil ice content to better understand the potential risk of abrupt permafrost thaw triggered by melting ground ice, a key open question associated with permafrost response to a warming Arctic. Our spatially resolved simulations of a well-characterized site in polygonal tundra near Utqiagvik, Alaska, agree well with multiple types of observations in the current climate. Projections indicate 63 cm of bulk subsidence from 2006 to 2100 in the strong-warming Representative Concentration Pathway 8.5 climate. Permafrost thaw as measured by the increase in active layer thickness (ALT)—the thickness of the soil layer that thaws each summer—is accelerated by subsidence, but the effect is relatively small. The ALT increases from the current-day value of approximately 50 cm to approximately 180 cm by 2100 when subsidence is included compared to about 160 cm when it is neglected. In these simulations, previously identified positive feedbacks between subsidence and thaw are self-limiting on decadal time frames because landscape runoff and increasing evapotranspiration result in drier tundra with weaker surface/atmosphere coupling. These results for a tundra site that is representative of large swathes of the Alaska North Slope suggest that subsidence is unlikely to lead to abrupt thaw overmore » large areas. However, subsidence does have significant effects on the hydrology of polygonal tundra. Specifically, subsidence increases landscape runoff, which helps maintain streamflow in the face of increased evapotranspiration but also causes drier tundra conditions that could have deleterious effects on sensitive Arctic wetland ecosystems.« less

Authors:

Painter, Scott L.  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-0901-6987"

Coon, Ethan T.  ^[1];

• Search DOE PAGES for author "Coon, Ethan T."
• Search DOE PAGES for ORCID "0000-0001-8124-9622"

Khattak, Ahmad Jan  ^[1];

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• Search DOE PAGES for ORCID "0000-0003-2781-7857"

Jastrow, Julie D.  ^[2]

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• Search DOE PAGES for ORCID "0000-0001-7069-4560"

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+ Show Author Affiliations

1. Climate Change Science Institute and Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831
2. Environmental Science Division, Argonne National Laboratory, Lemont IL 60439

Publication Date:

Mon Feb 13 00:00:00 EST 2023

Research Org.:

Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Argonne National Laboratory (ANL), Argonne, IL (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Biological and Environmental Research (BER); USDOE Office of Science (SC), Biological and Environmental Research (BER), Terrestrial Ecosystem Science Program

OSTI Identifier:

1924370

Alternate Identifier(s):

OSTI ID: 1959633; OSTI ID: 1967870

Grant/Contract Number:  

AC02-06CH11357; AC05-00OR22725

Resource Type:

Published Article

Journal Name:

Proceedings of the National Academy of Sciences of the United States of America

Additional Journal Information:

Journal Name: Proceedings of the National Academy of Sciences of the United States of America Journal Volume: 120 Journal Issue: 8; Journal ID: ISSN 0027-8424

Publisher:

Proceedings of the National Academy of Sciences

Country of Publication:

United States

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES; permafrost; active layer; climate change; thermokarst