Evaluating permafrost physics in the CMIP6 models and their sensitivity to climate change
Permafrost is an important component of the Arctic system and its future fate is likely to control changes in northern high latitude hydrology and biogeochemistry. Here we evaluate the permafrost dynamics in the global models participating in the Coupled Model Intercomparison Project (present genera...
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ftcopernicus:oai:publications.copernicus.org:tcd82398 2023-05-15T15:11:09+02:00 Evaluating permafrost physics in the CMIP6 models and their sensitivity to climate change Burke, Eleanor J. Zhang, Yu Krinner, Gerhard 2020-02-07 application/pdf https://doi.org/10.5194/tc-2019-309 https://tc.copernicus.org/preprints/tc-2019-309/ eng eng doi:10.5194/tc-2019-309 https://tc.copernicus.org/preprints/tc-2019-309/ eISSN: 1994-0424 Text 2020 ftcopernicus https://doi.org/10.5194/tc-2019-309 2020-07-20T16:22:26Z Permafrost is an important component of the Arctic system and its future fate is likely to control changes in northern high latitude hydrology and biogeochemistry. Here we evaluate the permafrost dynamics in the global models participating in the Coupled Model Intercomparison Project (present generation – CMIP6; previous generation – CMIP5) along with the the sensitivity of permafrost to climate change. Whilst the northern high latitude air temperatures are relatively well simulated by the climate models, they do introduce a bias into any subsequent model estimate of permafrost. Therefore evaluation metrics are defined in relation to the air temperature. This paper shows the climate, snow and permafrost physics of the CMIP6 multi-model ensemble is very similar to that of the CMIP5 multi-model ensemble. The main difference is that a small number of models have demonstrably better snow insulation in CMIP6 than in CMIP5 which improves their representation of the permafrost extent. The simulation of maximum summer thaw depth does not improve between CMIP5 and CMIP6. We suggest that models should include a better resolved and deeper soil profile as a first step towards addressing this. We use the annual mean thawed volume of the top 2 m of the soil defined from the model soil profiles for the permafrost region to quantify changes in permafrost dynamics. The CMIP6 models suggest this is projected to increase by 20–30 %/°C of global mean temperature increase. Under climate change and in equilibrium this may result in an additional 80–120 Gt C/°C of permafrost carbon becoming vulnerable to decomposition. Text Arctic Climate change permafrost Copernicus Publications: E-Journals Arctic |
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Copernicus Publications: E-Journals |
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English |
description |
Permafrost is an important component of the Arctic system and its future fate is likely to control changes in northern high latitude hydrology and biogeochemistry. Here we evaluate the permafrost dynamics in the global models participating in the Coupled Model Intercomparison Project (present generation – CMIP6; previous generation – CMIP5) along with the the sensitivity of permafrost to climate change. Whilst the northern high latitude air temperatures are relatively well simulated by the climate models, they do introduce a bias into any subsequent model estimate of permafrost. Therefore evaluation metrics are defined in relation to the air temperature. This paper shows the climate, snow and permafrost physics of the CMIP6 multi-model ensemble is very similar to that of the CMIP5 multi-model ensemble. The main difference is that a small number of models have demonstrably better snow insulation in CMIP6 than in CMIP5 which improves their representation of the permafrost extent. The simulation of maximum summer thaw depth does not improve between CMIP5 and CMIP6. We suggest that models should include a better resolved and deeper soil profile as a first step towards addressing this. We use the annual mean thawed volume of the top 2 m of the soil defined from the model soil profiles for the permafrost region to quantify changes in permafrost dynamics. The CMIP6 models suggest this is projected to increase by 20–30 %/°C of global mean temperature increase. Under climate change and in equilibrium this may result in an additional 80–120 Gt C/°C of permafrost carbon becoming vulnerable to decomposition. |
format |
Text |
author |
Burke, Eleanor J. Zhang, Yu Krinner, Gerhard |
spellingShingle |
Burke, Eleanor J. Zhang, Yu Krinner, Gerhard Evaluating permafrost physics in the CMIP6 models and their sensitivity to climate change |
author_facet |
Burke, Eleanor J. Zhang, Yu Krinner, Gerhard |
author_sort |
Burke, Eleanor J. |
title |
Evaluating permafrost physics in the CMIP6 models and their sensitivity to climate change |
title_short |
Evaluating permafrost physics in the CMIP6 models and their sensitivity to climate change |
title_full |
Evaluating permafrost physics in the CMIP6 models and their sensitivity to climate change |
title_fullStr |
Evaluating permafrost physics in the CMIP6 models and their sensitivity to climate change |
title_full_unstemmed |
Evaluating permafrost physics in the CMIP6 models and their sensitivity to climate change |
title_sort |
evaluating permafrost physics in the cmip6 models and their sensitivity to climate change |
publishDate |
2020 |
url |
https://doi.org/10.5194/tc-2019-309 https://tc.copernicus.org/preprints/tc-2019-309/ |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Climate change permafrost |
genre_facet |
Arctic Climate change permafrost |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-2019-309 https://tc.copernicus.org/preprints/tc-2019-309/ |
op_doi |
https://doi.org/10.5194/tc-2019-309 |
_version_ |
1766342055058997248 |