Information on the early Holocene climate constrains the summer sea ice projections for the 21st century

Goosse, Hugues; Driesschaert, E.; Fichefet, Thierry; Loutre, Marie-France

doi:10.5194/cp-3-683-2007

Cited by 37 publications

(25 citation statements)

References 38 publications

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“…2 W m −2 globally higher for 1976 to 2005 as compared to 1750) due to greenhouse-gas concentrations. Goosse et al (2007) found for LOVECLIM that the simulated sea-ice area fits reasonably well with modern-day observations. Our results confirm this, as we find that the simulated annual sea-ice area in our PRE2005 and 0kOG simulations (9.6 × 10 12 km 2 and 10.6 × 10 12 km 2 , respectively) agree well with observations (10.6 × 10 12 km 2 , cf.…”

Section: Modern Climatesupporting

confidence: 57%

The impact of early Holocene Arctic shelf flooding on climate in an atmosphere–ocean–sea–ice model

Blaschek¹,

Renssen²

2013

Clim. Past

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Abstract. Glacial terminations are characterized by a strong rise in sea level related to melting ice sheets. This rise in sea level is not uniform all over the world, because regional effects (uplift and subsidence of coastal zones) are superimposed on global trends. During the early Holocene the Siberian Shelf became flooded before 7.5 ka BP and the coastline reached modern-day high stands at 5 ka BP. This area is currently known as a sea-ice production area and contributes significantly to the sea-ice exported from the Arctic through the Fram Strait. This leads to the following hypothesis: during times of rising sea levels, shelves become flooded, increasing sea-ice production on these shelves, increasing sea-ice volume and export through the Fram Strait and causing the sea-ice extent to advance in the Nordic Seas, yielding cooler and fresher sea surface conditions. We have tested this hypothesis in an atmosphere-ocean-sea-ice coupled model of intermediate complexity (LOVECLIM). Our experiment on early Holocene Siberian Shelf flooding shows that in our model sea-ice production in the Northern Hemisphere increases (15 %) and that sea-ice extent in the Northern Hemisphere increases (14 %) but sea-ice export decreases (−15 %) contrary to our hypothesis. The reason of this unexpected behaviour has its origin in a weakened polar vortex, induced by the land-ocean changes due to the shelf flooding, and a resulting decrease of zonality in the Nordic Seas pressure regime. Hence the winter Greenland high and the Icelandic low strengthen, yielding stronger winds on both sides of the Nordic Seas. Increased winds along the East Greenland Current support local sea-ice production and transport towards the South, resulting in a wider sea-ice cover and a southward shift of convection areas. The overall strength of the Atlantic meridional overturning circulation is reduced by 4 % and the heat transport in the Atlantic basin by 7 %, resulting in an annual cooling pattern over the Nordic Seas by up to −4 • C. We find that the flooding of the Siberian shelf resulting from an orbitally induced warming and related glacioeustatic sea level rise causes a Nordic Seas cooling feedback opposed to this warming.

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Section: Modern Climatesupporting

confidence: 57%

The impact of early Holocene Arctic shelf flooding on climate in an atmosphere–ocean–sea–ice model

Blaschek¹,

Renssen²

2013

Clim. Past

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“…The different simulations examined in this study were performed with LOVECLIM1.1 Goosse et al, 2007), a three-dimensional climate model of intermediate complexity which includes representations of the atmosphere, the ocean and sea ice, the terrestrial biosphere, the oceanic carbon cycle and the polar ice sheets. As the last two components were not activated in this study, they will not be described here.…”

Section: Model Description and Experimental Designmentioning

confidence: 99%

The 15th century Arctic warming in coupled model simulations with data assimilation

et al. 2009

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Abstract. An ensemble of simulations of the climate of the past millennium conducted with a three-dimensional climate model of intermediate complexity are constrained to follow temperature histories obtained from a recent compilation of well-calibrated surface temperature proxies using a simple data assimilation technique. Those simulations provide a reconstruction of the climate of the Arctic that is compatible with the model physics, the forcing applied and the proxy records. Available observational data, proxybased reconstructions and our model results suggest that the Arctic climate is characterized by substantial variations in surface temperature over the past millennium. Though the most recent decades are likely to be the warmest of the past millennium, we find evidence for substantial past warming episodes in the Arctic. In particular, our model reconstructions show a prominent warm event during the period 1470-1520. This warm period is likely related to the internal variability of the climate system, that is the variability present in the absence of any change in external forcing. We examine the roles of competing mechanisms that could potentially produce this anomaly. This study leads us to conclude that changes in atmospheric circulation, through enhanced southwesterly winds towards northern Europe, Siberia and Canada, are likely the main cause of the late 15th/early 16th century Arctic warming.

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“…As has been suggested by Goosse et al (2007) one may obtain stronger response in the Arctic and smaller and thinner sea-ice covers if one considers the earlier part of the Holocene (around 9 to 8 ka BP) rather than the midHolocene. This may be a better period to use for investigation of the model response to the changes in solar insolation, since the orbital insolation forcing was stronger then.…”

Section: Discussionmentioning

confidence: 72%

“…5 are smaller for many of the models than the observed change in ice cover over the last 30 yr. Thus, it cannot be ruled out that internal model variability may obscure the response to the orbital forcing in some of the models with a weak response (Goosse et al, 2007).…”

Section: Discussionmentioning

confidence: 99%

The sensitivity of the Arctic sea ice to orbitally induced insolation changes: a study of the mid-Holocene Paleoclimate Modelling Intercomparison Project 2 and 3 simulations

2013

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Abstract. In the present work the Arctic sea ice in the mid-Holocene and the pre-industrial climates are analysed and compared on the basis of climate-model results from the Paleoclimate Modelling Intercomparison Project phase 2 (PMIP2) and phase 3 (PMIP3). The PMIP3 models generally simulate smaller and thinner sea-ice extents than the PMIP2 models both for the pre-industrial and the mid-Holocene climate. Further, the PMIP2 and PMIP3 models all simulate a smaller and thinner Arctic summer sea-ice cover in the mid-Holocene than in the pre-industrial control climate. The PMIP3 models also simulate thinner winter sea ice than the PMIP2 models. The winter sea-ice extent response, i.e. the difference between the mid-Holocene and the pre-industrial climate, varies among both PMIP2 and PMIP3 models. Approximately one half of the models simulate a decrease in winter sea-ice extent and one half simulates an increase. The model-mean summer sea-ice extent is 11 % (21 %) smaller in the mid-Holocene than in the pre-industrial climate simulations in the PMIP2 (PMIP3). In accordance with the simple model of Thorndike (1992), the sea-ice thickness response to the insolation change from the pre-industrial to the mid-Holocene is stronger in models with thicker ice in the pre-industrial climate simulation. Further, the analyses show that climate models for which the Arctic sea-ice responses to increasing atmospheric CO2 concentrations are similar may simulate rather different sea-ice responses to the change in solar forcing between the mid-Holocene and the pre-industrial. For two specific models, which are analysed in detail, this difference is found to be associated with differences in the simulated cloud fractions in the summer Arctic; in the model with a larger cloud fraction the effect of insolation change is muted. A sub-set of the mid-Holocene simulations in the PMIP ensemble exhibit open water off the north-eastern coast of Greenland in summer, which can provide a fetch for surface waves. This is in broad agreement with recent analyses of sea-ice proxies, indicating that beach-ridges formed on the north-eastern coast of Greenland during the early- to mid-Holocene.

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Information on the early Holocene climate constrains the summer sea ice projections for the 21st century

Cited by 37 publications

References 38 publications

The impact of early Holocene Arctic shelf flooding on climate in an atmosphere–ocean–sea–ice model

The impact of early Holocene Arctic shelf flooding on climate in an atmosphere–ocean–sea–ice model

The 15th century Arctic warming in coupled model simulations with data assimilation

The sensitivity of the Arctic sea ice to orbitally induced insolation changes: a study of the mid-Holocene Paleoclimate Modelling Intercomparison Project 2 and 3 simulations

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