Warm Greenland during the last interglacial: the role of regional  changes in sea ice cover

Merz, Niklaus; Born, Andreas; Raible, Christoph C.; Stocker, Thomas F.

doi:10.5194/cp-2016-12

Cited by 13 publications

(27 citation statements)

References 35 publications

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“…Confirming the suggestion of Sime et al (2013), Merz et al (2016) used the CCSM3 and CCSM4 models to demonstrate that the large spread in Greenland SAT change among the LIG equilibrium simulations (Fig. 4, Lunt et al, 2013) is mostly due to differences in simulated sea ice extent.…”

Section: Lig Temperatures In Greenland As Estimated By Climate Modelssupporting

confidence: 52%

“…State-of-the-art intermediate complexity or fully coupled climate models mostly produce an annual mean temperature increase of less than 2 • C above preindustrial values during the LIG in NW Greenland. However, sea ice cover retreat in the Nordic Seas and changes in Greenland ice sheet topography may significantly enhance surface warming (Merz et al, 2014a(Merz et al, , 2016 and therefore reduce the gap with our estimate. Vice versa, relaxing the ice sheet thickness constraint derived from the ice core measurements (NEEM community members, 2013) allows for much stronger surface warming at the LIG deposition sites.…”

Section: Discussionmentioning

confidence: 63%

“…A comparison of some of the model outputs (presented in Lunt et al, 2013) shows very limited accumulation increase (less than 5 %) over central Greenland. Stronger increases in accumulation rate in the LIG associated with significantly warmer than preindustrial temperature were obtained in relation to a reduction of sea ice in the Nordic Seas (10 % increase in accumulation; Merz et al, 2016). Finally, it has been shown that the geometry of the Greenland ice sheet and topographic changes can lead to various local accumulation scenarios for the LIG at the upstream NEEM deposition site (Merz et al, 2014b): depending on the prescribed LIG ice sheet topography, the modeled accumulation rate at LIG can be 25 % lower to 13 % higher than the preindustrial accumulation rate.…”

Section: Different Estimates Of the Link Betweenmentioning

confidence: 95%

“…This paradox was further enhanced by the difficulty of coupled ocean-atmosphere climate models to capture such warming (Otto-Bliesner et al, 2013b;Capron et al, 2014), even during the warmest summer months , and by the inconsistency of the Greenland ice sheet retreat simulated by ice sheet models in response to such warming (e.g., Stone et al, 2013;Helsen et al, 2013). When accounting for a reduced Greenland ice sheet and a retreat in sea ice cover in the Nordic Seas, atmospheric simulations can explain up to 5 • C annual mean warming with respect to the preindustrial period (Merz et al, 2014a(Merz et al, , 2016. Moreover, all LIG climate modeling studies cited above strongly enhance summer precipitation seasonality in Greenland, suggesting a summer bias for LIG δ 18 O ice and weaker annual mean change than the initial estimate of 8 ± 4 • C Merz et al, 2014b).…”

Section: Introductionmentioning

confidence: 99%

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How warm was Greenland during the last interglacial period?

et al. 2016

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Abstract. The last interglacial period (LIG, ∼ 129-116 thousand years ago) provides the most recent case study of multimillennial polar warming above the preindustrial level and a response of the Greenland and Antarctic ice sheets to this warming, as well as a test bed for climate and ice sheet models. Past changes in Greenland ice sheet thickness and surface temperature during this period were recently derived from the North Greenland Eemian Ice Drilling (NEEM) ice core records, northwest Greenland. The NEEM paradox has emerged from an estimated large local warming above the preindustrial level (7.5 ± 1.8 • C at the deposition site 126 kyr ago without correction for any overall ice sheet altitude changes between the LIG and the preindustrial period) based on water isotopes, together with limited local ice thinning, suggesting more resilience of the real Greenland ice sheet than shown in some ice sheet models. Here, we provide an independent assessment of the average LIG Greenland surface warming using ice core air isotopic composition (δ 15 N) and relationships between accumulation rate and temperature. The LIG surface temperature at the upstream NEEM deposition site without ice sheet altitude correction is estimated to be warmer by +8.5 ± 2.5 • C compared to the preindustrial period. This temperature estimate is consistent with the 7.5 ± 1.8 • C warming initially determined from NEEM water isotopes but at the upper end of the preindustrial period to LIG temperature difference of +5.2 ± 2.3 • C obtained at the NGRIP (North Greenland Ice Core Project) site by the same method. Climate simulations performed with present-day ice sheet topography lead in general to a warming smaller than reconstructed, but sensitivity tests show that larger amplitudes (up to 5 • C) are produced in response to prescribed changes in sea ice extent and ice sheet topography.

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Section: Lig Temperatures In Greenland As Estimated By Climate Modelssupporting

confidence: 52%

Section: Discussionmentioning

confidence: 63%

Section: Different Estimates Of the Link Betweenmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

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How warm was Greenland during the last interglacial period?

et al. 2016

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“…Unfortunately, the uncertainties associated with the global climate simulation add a major constraint to any high resolution Greenland SMB estimate. For example, Eemian global climate model spread has been hypothesized to be related to 15 differences in the simulated Eemian sea ice cover (Merz et al, 2016). Furthermore, sensitivity experiments with global climate models by Merz et al (2016) show that sea ice cover in the Nordic Seas is crucial for Greenland temperatures (i.e., a substantial reduction in sea ice cover is necessary to simulate warmer Eemian Greenland temperatures in agreement with ice core proxy data).…”

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confidence: 99%

Eemian Greenland Surface Mass Balance strongly sensitive to SMB model choice

Plach¹,

Nisancioglu²,

clec’h³

et al. 2018

Preprint

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Abstract. Understanding the behavior of the Greenland ice sheet in a warmer climate, and particularly its surface mass balance (SMB), is important for assessing Greenland's potential contribution to future sea level rise. The Eemian interglacial, the most recent warmer-than-present period in Earth's history approximately 125,000 years ago, provides an analogue for a warm summer climate over Greenland. The Eemian is characterized by a positive Northern Hemisphere summer insolation anomaly, which introduces uncertainties in Eemian SMB when using positive degree day estimates. In this study, we use Eemian global 5 and regional climate simulations in combination with three types of SMB models -a simple positive degree day, an intermediate complexity, and a full surface energy balance model -to evaluate the importance of regional climate and model complexity for estimates of Greenland SMB. We find that all SMB models perform well under the relatively cool pre-industrial and late Eemian. For the relatively warm early Eemian, the differences between SMB models are large which is associated with the representation of insolation in the respective models. For all simulated time slices there is a systematic difference between 10 globally and regionally forced SMB models, due to the different representation of the regional climate over Greenland. We conclude that both the resolution of the simulated climate as well as the method used to estimate the SMB, are important for an accurate simulation of Greenland's SMB. Whether model resolution or SMB method is most important depends on the climate state and in particular the prevailing insolation pattern. We suggest that future Eemian climate model inter-comparison studies are combined with different SMB models to quantify Eemian SMB uncertainty estimates.

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Simulating the Last Interglacial Greenland stable water isotope peak: The role of Arctic sea ice changes

Malmierca‐Vallet

Sime

Tindall

et al. 2018

Quaternary Science Reviews

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Last Interglacial (LIG), stable water isotope values (18 O) measured in Greenland deep ice cores are at least 2.5‰ higher compared to the present day. Previous isotopic climate simulations of the LIG do not capture the observed Greenland 18 O increases. Here, we use the isotope-enabled HadCM3 (UK Met Office coupled atmosphere-ocean general circulation model) to investigate whether a retreat of Northern Hemisphere sea ice was responsible for this model-data disagreement. Our results highlight the potential significance of sea ice changes on the LIG Greenland isotopic maximum. Sea ice loss in combination with increased sea surface temperatures, over the Arctic, affect 18 O: water vapour enriched in heavy isotopes and a shorter distillation path may both increase 18 O values over Greenland. We show, for the first time, that simulations of the response to Arctic sea ice reduction are capable of producing the likely magnitude of LIG 18 O increases at NEEM, NGRIP, GIPS2 and Camp Century ice core sites. However, we may underestimate 18 O changes at the Renland, DYE3 and GRIP ice core locations. Accounting for possible ice sheet changes is likely to be required to produce a better fit to the ice core measurements.

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Warm Greenland during the last interglacial: the role of regional changes in sea ice cover

Cited by 13 publications

References 35 publications

How warm was Greenland during the last interglacial period?

How warm was Greenland during the last interglacial period?

Eemian Greenland Surface Mass Balance strongly sensitive to SMB model choice

Simulating the Last Interglacial Greenland stable water isotope peak: The role of Arctic sea ice changes

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