Detecting the permafrost carbon feedback: Talik formation and increased cold-season respiration as precursors to sink-to-source transitions
Thaw and release of permafrost carbon (C) due to climate change is likely to offset increased vegetation C uptake in northern high-latitude (NHL) terrestrial ecosystems. Models project that this permafrost C feedback may act as a slow leak, in which case detection and attribution of the feedback may...
Main Authors: | , , , , |
---|---|
Format: | Article in Journal/Newspaper |
Language: | unknown |
Published: |
eScholarship, University of California
2018
|
Subjects: | |
Online Access: | https://escholarship.org/uc/item/5z6634d2 |
id |
ftcdlib:oai:escholarship.org/ark:/13030/qt5z6634d2 |
---|---|
record_format |
openpolar |
spelling |
ftcdlib:oai:escholarship.org/ark:/13030/qt5z6634d2 2023-05-15T15:08:02+02:00 Detecting the permafrost carbon feedback: Talik formation and increased cold-season respiration as precursors to sink-to-source transitions Parazoo, NC Koven, CD Lawrence, DM Romanovsky, V Miller, CE 123 - 144 2018-01-12 application/pdf https://escholarship.org/uc/item/5z6634d2 unknown eScholarship, University of California qt5z6634d2 https://escholarship.org/uc/item/5z6634d2 public Cryosphere, vol 12, iss 1 Meteorology & Atmospheric Sciences Oceanography Physical Geography and Environmental Geoscience article 2018 ftcdlib 2021-04-16T07:11:45Z Thaw and release of permafrost carbon (C) due to climate change is likely to offset increased vegetation C uptake in northern high-latitude (NHL) terrestrial ecosystems. Models project that this permafrost C feedback may act as a slow leak, in which case detection and attribution of the feedback may be difficult. The formation of talik, a subsurface layer of perennially thawed soil, can accelerate permafrost degradation and soil respiration, ultimately shifting the C balance of permafrost-affected ecosystems from long-term C sinks to long-term C sources. It is imperative to understand and characterize mechanistic links between talik, permafrost thaw, and respiration of deep soil C to detect and quantify the permafrost C feedback. Here, we use the Community Land Model (CLM) version 4.5, a permafrost and biogeochemistry model, in comparison to long-term deep borehole data along North American and Siberian transects, to investigate thaw-driven C sources in NHL ( > 55° N) from 2000 to 2300. Widespread talik at depth is projected across most of the NHL permafrost region (14 millionĝ€†km2) by 2300, 6.2 millionĝ€†km2 of which is projected to become a long-term C source, emitting 10 Pgĝ€†C by 2100, 50 Pgĝ€†C by 2200, and 120 Pgĝ€†C by 2300, with few signs of slowing. Roughly half of the projected C source region is in predominantly warm sub-Arctic permafrost following talik onset. This region emits only 20 Pgĝ€†C by 2300, but the CLM4.5 estimate may be biased low by not accounting for deep C in yedoma. Accelerated decomposition of deep soil C following talik onset shifts the ecosystem C balance away from surface dominant processes (photosynthesis and litter respiration), but sink-to-source transition dates are delayed by 20-200 years by high ecosystem productivity, such that talik peaks early ( ĝ1/4 2050s, although borehole data suggest sooner) and C source transition peaks late ( ĝ1/4 2150-2200). The remaining C source region in cold northern Arctic permafrost, which shifts to a net source early (late 21st century), emits 5 times more C (95 Pgĝ€†C) by 2300, and prior to talik formation due to the high decomposition rates of shallow, young C in organic-rich soils coupled with low productivity. Our results provide important clues signaling imminent talik onset and C source transition, including (1) late cold-season (January-February) soil warming at depth ( ĝ1/4 2 m), (2) increasing cold-season emissions (November-April), and (3) enhanced respiration of deep, old C in warm permafrost and young, shallow C in organic-rich cold permafrost soils. Our results suggest a mosaic of processes that govern carbon source-to-sink transitions at high latitudes and emphasize the urgency of monitoring soil thermal profiles, organic C age and content, cold-season CO2 emissions, and atmospheric 14CO2 as key indicators of the permafrost C feedback. Article in Journal/Newspaper Arctic Climate change permafrost University of California: eScholarship Arctic Talik ENVELOPE(146.601,146.601,59.667,59.667) |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
Meteorology & Atmospheric Sciences Oceanography Physical Geography and Environmental Geoscience |
spellingShingle |
Meteorology & Atmospheric Sciences Oceanography Physical Geography and Environmental Geoscience Parazoo, NC Koven, CD Lawrence, DM Romanovsky, V Miller, CE Detecting the permafrost carbon feedback: Talik formation and increased cold-season respiration as precursors to sink-to-source transitions |
topic_facet |
Meteorology & Atmospheric Sciences Oceanography Physical Geography and Environmental Geoscience |
description |
Thaw and release of permafrost carbon (C) due to climate change is likely to offset increased vegetation C uptake in northern high-latitude (NHL) terrestrial ecosystems. Models project that this permafrost C feedback may act as a slow leak, in which case detection and attribution of the feedback may be difficult. The formation of talik, a subsurface layer of perennially thawed soil, can accelerate permafrost degradation and soil respiration, ultimately shifting the C balance of permafrost-affected ecosystems from long-term C sinks to long-term C sources. It is imperative to understand and characterize mechanistic links between talik, permafrost thaw, and respiration of deep soil C to detect and quantify the permafrost C feedback. Here, we use the Community Land Model (CLM) version 4.5, a permafrost and biogeochemistry model, in comparison to long-term deep borehole data along North American and Siberian transects, to investigate thaw-driven C sources in NHL ( > 55° N) from 2000 to 2300. Widespread talik at depth is projected across most of the NHL permafrost region (14 millionĝ€†km2) by 2300, 6.2 millionĝ€†km2 of which is projected to become a long-term C source, emitting 10 Pgĝ€†C by 2100, 50 Pgĝ€†C by 2200, and 120 Pgĝ€†C by 2300, with few signs of slowing. Roughly half of the projected C source region is in predominantly warm sub-Arctic permafrost following talik onset. This region emits only 20 Pgĝ€†C by 2300, but the CLM4.5 estimate may be biased low by not accounting for deep C in yedoma. Accelerated decomposition of deep soil C following talik onset shifts the ecosystem C balance away from surface dominant processes (photosynthesis and litter respiration), but sink-to-source transition dates are delayed by 20-200 years by high ecosystem productivity, such that talik peaks early ( ĝ1/4 2050s, although borehole data suggest sooner) and C source transition peaks late ( ĝ1/4 2150-2200). The remaining C source region in cold northern Arctic permafrost, which shifts to a net source early (late 21st century), emits 5 times more C (95 Pgĝ€†C) by 2300, and prior to talik formation due to the high decomposition rates of shallow, young C in organic-rich soils coupled with low productivity. Our results provide important clues signaling imminent talik onset and C source transition, including (1) late cold-season (January-February) soil warming at depth ( ĝ1/4 2 m), (2) increasing cold-season emissions (November-April), and (3) enhanced respiration of deep, old C in warm permafrost and young, shallow C in organic-rich cold permafrost soils. Our results suggest a mosaic of processes that govern carbon source-to-sink transitions at high latitudes and emphasize the urgency of monitoring soil thermal profiles, organic C age and content, cold-season CO2 emissions, and atmospheric 14CO2 as key indicators of the permafrost C feedback. |
format |
Article in Journal/Newspaper |
author |
Parazoo, NC Koven, CD Lawrence, DM Romanovsky, V Miller, CE |
author_facet |
Parazoo, NC Koven, CD Lawrence, DM Romanovsky, V Miller, CE |
author_sort |
Parazoo, NC |
title |
Detecting the permafrost carbon feedback: Talik formation and increased cold-season respiration as precursors to sink-to-source transitions |
title_short |
Detecting the permafrost carbon feedback: Talik formation and increased cold-season respiration as precursors to sink-to-source transitions |
title_full |
Detecting the permafrost carbon feedback: Talik formation and increased cold-season respiration as precursors to sink-to-source transitions |
title_fullStr |
Detecting the permafrost carbon feedback: Talik formation and increased cold-season respiration as precursors to sink-to-source transitions |
title_full_unstemmed |
Detecting the permafrost carbon feedback: Talik formation and increased cold-season respiration as precursors to sink-to-source transitions |
title_sort |
detecting the permafrost carbon feedback: talik formation and increased cold-season respiration as precursors to sink-to-source transitions |
publisher |
eScholarship, University of California |
publishDate |
2018 |
url |
https://escholarship.org/uc/item/5z6634d2 |
op_coverage |
123 - 144 |
long_lat |
ENVELOPE(146.601,146.601,59.667,59.667) |
geographic |
Arctic Talik |
geographic_facet |
Arctic Talik |
genre |
Arctic Climate change permafrost |
genre_facet |
Arctic Climate change permafrost |
op_source |
Cryosphere, vol 12, iss 1 |
op_relation |
qt5z6634d2 https://escholarship.org/uc/item/5z6634d2 |
op_rights |
public |
_version_ |
1766339464464957440 |