Eurasian permafrost instability constrained by reduced sea-ice cover

Vandenberghe, Jef; Renssen, H.; Roche, Didier M.; Goosse, Hugues; Velichko, Andrei; Gorbunov, Aldar P.; Levavasseur, Guillaume

doi:10.1016/j.quascirev.2011.12.001

Cited by 58 publications

(70 citation statements)

References 35 publications

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“…Over Eurasia permafrost is generally thicker than in the present day and extends almost as far south as 50 • N over Europe and southwestern Russia. This is close to the estimates given by Vandenberghe et al (2012), although they support an expansion of permafrost even further south over Europe. However, the estimates of Vandenberghe et al (2012) include also discontinuous permafrost.…”

Section: Permafrost-ice-sheet Evolution Over the Last Glacial Cyclesupporting

confidence: 90%

“…This is close to the estimates given by Vandenberghe et al (2012), although they support an expansion of permafrost even further south over Europe. However, the estimates of Vandenberghe et al (2012) include also discontinuous permafrost. The modeled permafrost extent is in even better agreement with the continuous permafrost extent estimates in Vandenberghe et al (2014).…”

Section: Permafrost-ice-sheet Evolution Over the Last Glacial Cyclesupporting

confidence: 90%

“…present south of the margin of the Laurentide ice sheet (Saito et al, 2013;Vandenberghe et al, 2012).…”

Section: Discussionmentioning

confidence: 99%

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Coupled Northern Hemisphere permafrost–ice-sheet evolution over the last glacial cycle

Willeit

Ganopolski

2015

Clim. Past

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Abstract. Permafrost influences a number of processes which are relevant for local and global climate. For example, it is well known that permafrost plays an important role in global carbon and methane cycles. Less is known about the interaction between permafrost and ice sheets. In this study a permafrost module is included in the Earth system model CLIMBER-2, and the coupled Northern Hemisphere (NH) permafrost-ice-sheet evolution over the last glacial cycle is explored.The model performs generally well at reproducing present-day permafrost extent and thickness. Modeled permafrost thickness is sensitive to the values of ground porosity, thermal conductivity and geothermal heat flux. Permafrost extent at the Last Glacial Maximum (LGM) agrees well with reconstructions and previous modeling estimates.Present-day permafrost thickness is far from equilibrium over deep permafrost regions. Over central Siberia and the Arctic Archipelago permafrost is presently up to 200-500 m thicker than it would be at equilibrium. In these areas, present-day permafrost depth strongly depends on the past climate history and simulations indicate that deep permafrost has a memory of surface temperature variations going back to at least 800 ka.Over the last glacial cycle permafrost has a relatively modest impact on simulated NH ice sheet volume except at LGM, when including permafrost increases ice volume by about 15 m sea level equivalent in our model. This is explained by a delayed melting of the ice base from below by the geothermal heat flux when the ice sheet sits on a porous sediment layer and permafrost has to be melted first. Permafrost affects ice sheet dynamics only when ice extends over areas covered by thick sediments, which is the case at LGM.

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Section: Permafrost-ice-sheet Evolution Over the Last Glacial Cyclesupporting

confidence: 90%

Section: Permafrost-ice-sheet Evolution Over the Last Glacial Cyclesupporting

confidence: 90%

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Coupled Northern Hemisphere permafrost–ice-sheet evolution over the last glacial cycle

Willeit

Ganopolski

2015

Clim. Past

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“…At LGM, the area of permafrost on land was larger than today (Vandenberghe et al, 2012), but not much information on soil carbon has been conserved, especially if it has long since decayed as a result of permafrost degradation during the last termination. To constrain the total carbon content in permafrost soils we use the estimates of ; for total land carbon these are 3640 ± 400 GtC at LGM and 3970 ± 325 GtC at PI, with a total change of +330 GtC between LGM and PI.…”

Section: Tuning the Soil Carbon Modelmentioning

confidence: 99%

“…The importance of soil depth (lower boundary conditions) was also highlighted; Alexeev et al (2007) demonstrated that the longer the simulation, the larger is the soil column depth required in order to produce reliable thermal diffusion-based temperature calculations: a 4 m soil depth can produce reliable temperature predictions for a 2 year simulation, and for a 200 year simulation a 30 m soil depth would be required. Van Huissteden and Dolman (2012) reviewed Arctic soil carbon stocks estimates and the permafrost-carbon feedback. They note the processes by which carbon loss occurs from thawing permafrost including active layer thickening (also caused by vegetation disturbance), thermokarst formation, dissolved organic carbon (DOC) export, fire and other disturbances.…”

Section: Introductionmentioning

confidence: 99%

A simplified permafrost-carbon model for long-term climate studies with the CLIMBER-2 coupled earth system model

et al. 2014

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Abstract. We present the development and validation of a simplified permafrost-carbon mechanism for use with the land surface scheme operating in the CLIMBER-2 earth system model. The simplified model estimates the permafrost fraction of each grid cell according to the balance between modelled cold (below 0 • C) and warm (above 0 • C) days in a year. Areas diagnosed as permafrost are assigned a reduction in soil decomposition rate, thus creating a slow accumulating soil carbon pool. In warming climates, permafrost extent reduces and soil decomposition rates increase, resulting in soil carbon release to the atmosphere. Four accumulation/decomposition rate settings are retained for experiments within the CLIMBER-2(P) model, which are tuned to agree with estimates of total land carbon stocks today and at the last glacial maximum. The distribution of this permafrost-carbon pool is in broad agreement with measurement data for soil carbon content. The level of complexity of the permafrostcarbon model is comparable to other components in the CLIMBER-2 earth system model.

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Coupling of VAMPERS within iLOVECLIM: experiments during the LGM and Last Deglaciation

Kitover

Renssen

Balen

et al. 2019

J Quaternary Science

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The VAMPERS (Vrije Universiteit Amsterdam Permafrost Snow Model) has been coupled within iLOVECLIM, an earth system model. This advancement allows the thermal coupling between permafrost and climate to be examined from a millennial timescale using equilibrium experiments during the Last Glacial Maximum (21 ka) and transient experiments for the subsequent deglaciation period (21–11 ka). It appears that the role of permafrost during both stable and transitional (glacial–interglacial) climate periods is seasonal, resulting in cooler summers and warmer winters by approximately ±2 °C maximum. This conclusion reinforces the importance of including the active layer within climate models. In addition, the coupling of VAMPERS also yields a simulation of transient permafrost conditions, not only for estimating areal changes in extent but also total permafrost gain/loss.

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Eurasian permafrost instability constrained by reduced sea-ice cover

Cited by 58 publications

References 35 publications

Coupled Northern Hemisphere permafrost–ice-sheet evolution over the last glacial cycle

Coupled Northern Hemisphere permafrost–ice-sheet evolution over the last glacial cycle

A simplified permafrost-carbon model for long-term climate studies with the CLIMBER-2 coupled earth system model

Coupling of VAMPERS within iLOVECLIM: experiments during the LGM and Last Deglaciation

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