Warm climate isotopic simulations: what do we learn about interglacial signals in Greenland ice cores?

Sime, Louise; Risi, Camille; Tindall, Julia; Sjolte, Jesper; Wolff, Eric W.; Masson‐Delmotte, Valérie; Capron, Émilie

doi:10.1016/j.quascirev.2013.01.009

Cited by 50 publications

(104 citation statements)

References 71 publications

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“…However, it is highly likely that the Antarctic ice sheet was smaller than present by ∼ 127 ka, most probably because of the disappearance of the WAIS, and that the Greenland ice sheet was reduced in extent compared to present. Given that only about 3-4 m sea-level rise is covered by contributions from ocean thermal expansion (McKay et al, 2011), land-based glaciers (Marzeion et al, 2012), and melting of the Green-land ice sheet (NEEM Community Members, 2013;MassonDelmotte et al, 2013), the remaining sea-level rise is most likely to be linked to a mass loss from the Antarctic ice sheet. We propose a sensitivity experiment (lig127k-ais) to test the impact of a smaller-than-present Antarctic ice sheet, using a reduced ice-sheet configuration obtained from offline simulations with their own models or the model results such as those from DeConto and Pollard (2016) or Sutter et al (2016).…”

Section: Sensitivity To Prescribed Ice Sheetsmentioning

confidence: 99%

“…There will also be a major focus on the tropical water cycle. These analyses will exploit available data sets for the LIG which mostly document surface sea and air temperatures across the globe (Anderson et al, 2006;Brewer et al, 2008;Capron et al, 2014;Hoffman et al, 2017;McKay et al, 2011;Turney and Jones, 2010), although recent efforts also synthesize reconstructions of sea-ice changes (Esper and Gersonde, 2014;Sime et al, 2013), of the deep ocean circulation (Oliver et al, 2010), and to a lesser extent the tropical hydrological cycle . In addition, several existing maps are reporting vegetation changes at the NH high latitudes (Bennike et al, 2001) and changes in lake area in the Sahara (Petit-Maire, 1999).…”

Section: Paleoenvironmental Data and Climate Reconstructions For Compmentioning

confidence: 99%

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The PMIP4 contribution to CMIP6 – Part 2: Two interglacials, scientific objective and experimental design for Holocene and Last Interglacial simulations

et al. 2017

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Abstract. Two interglacial epochs are included in the suite of Paleoclimate Modeling Intercomparison Project (PMIP4) simulations in the Coupled Model Intercomparison Project (CMIP6). The experimental protocols for simulations of the mid-Holocene (midHolocene, 6000 years before present) and the Last Interglacial (lig127k, 127 000 years before present) are described here. These equilibrium simulations are designed to examine the impact of changes in orbital forcing at times when atmospheric greenhouse gas levels were similar to those of the preindustrial period and the continental configurations were almost identical to modern ones. These simulations test our understanding of the interplay between radiative forcing and atmospheric circulation, and the connections among large-scale and regional climate changes giving rise to phenomena such as land-sea contrast and highlatitude amplification in temperature changes, and responses of the monsoons, as compared to today. They also provide an opportunity, through carefully designed additional sensitivity experiments, to quantify the strength of atmosphere, ocean, cryosphere, and land-surface feedbacks. Sensitivity experiments are proposed to investigate the role of freshwater forcing in triggering abrupt climate changes within interglacial epochs. These feedback experiments naturally lead to a focus on climate evolution during interglacial periods, which will be examined through transient experiments. Analyses of the sensitivity simulations will also focus on interactions between extratropical and tropical circulation, and the relationship between changes in mean climate state and climate variability on annual to multi-decadal timescales. The comparative abundance of paleoenvironmental data and of quantitative climate reconstructions for the Holocene and Last Interglacial make these two epochs ideal candidates for systematic evaluation of model performance, and such comparisons will shed new light on the importance of external feedbacks (e.g., vegetation, dust) and the ability of state-of-the-art models to simulate climate changes realistically.

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Section: Sensitivity To Prescribed Ice Sheetsmentioning

confidence: 99%

Section: Paleoenvironmental Data and Climate Reconstructions For Compmentioning

confidence: 99%

The PMIP4 contribution to CMIP6 – Part 2: Two interglacials, scientific objective and experimental design for Holocene and Last Interglacial simulations

et al. 2017

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“…When we apply the temperature-δ 18 O relationship determined for the current interglacial, this translates into an Eemian temperature increase of 8 ± 4 • C (NEEM community members, 2013). Correspondingly, the NEEM δ 18 O record suggests an even stronger Eemian warming than measured in δ 15 N. Sime et al (2013) showed within isotopic simulations that a reduction in the winter sea ice cover around the northern half of Greenland, together with an increase in SSTs in the same region, is sufficient to cause a > 3 ‰ interglacial enrichment of δ 18 O in central Greenland snow. The changes in SST and sea ice further lead to higher δ 18 O-temperature gradients, so a > 3 ‰ enrichment in δ 18 O might rather correspond to a 5 • C warming, which would be more in line with δ 15 N. The underlying mechanism is that a reduction in sea ice increases the fraction of water vapor deposited in central Greenland originating from more local (isotopically enriched) sources at the expense of more distant (isotopically depleted) sources (Sime et al, 2013).…”

Section: Discussionmentioning

confidence: 79%

“…Correspondingly, the NEEM δ 18 O record suggests an even stronger Eemian warming than measured in δ 15 N. Sime et al (2013) showed within isotopic simulations that a reduction in the winter sea ice cover around the northern half of Greenland, together with an increase in SSTs in the same region, is sufficient to cause a > 3 ‰ interglacial enrichment of δ 18 O in central Greenland snow. The changes in SST and sea ice further lead to higher δ 18 O-temperature gradients, so a > 3 ‰ enrichment in δ 18 O might rather correspond to a 5 • C warming, which would be more in line with δ 15 N. The underlying mechanism is that a reduction in sea ice increases the fraction of water vapor deposited in central Greenland originating from more local (isotopically enriched) sources at the expense of more distant (isotopically depleted) sources (Sime et al, 2013). However, a meaningful interpretation of the NEEM δ 18 O record is further complicated by the fact that the Eemian warming in Greenland mainly occurs in summer (due to orbital forcing) but δ 18 O is rather tied to winter temperatures (Sjolte et al, 2014).…”

Section: Discussionmentioning

confidence: 79%

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

et al. 2016

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Abstract. The last interglacial, also known as the Eemian, is characterized by warmer than present conditions at high latitudes. This is implied by various Eemian proxy records as well as by climate model simulations, though the models mostly underestimate the warming with respect to proxies. Simulations of Eemian surface air temperatures (SAT) in the Northern Hemisphere extratropics further show large variations between different climate models, and it has been hypothesized that this model spread relates to diverse representations of the Eemian sea ice cover. Here we use versions 3 and 4 of the Community Climate System Model (CCSM3 and CCSM4) to highlight the crucial role of sea ice and sea surface temperatures changes for the Eemian climate, in particular in the North Atlantic sector and in Greenland. A substantial reduction in sea ice cover results in an amplified atmospheric warming and thus a better agreement with Eemian proxy records. Sensitivity experiments with idealized lower boundary conditions reveal that warming over Greenland is mostly due to a sea ice retreat in the Nordic Seas. In contrast, sea ice changes in the Labrador Sea have a limited local impact. Changes in sea ice cover in either region are transferred to the overlying atmosphere through anomalous surface energy fluxes. The large-scale spread of the warming resulting from a Nordic Seas sea ice retreat is mostly explained by anomalous heat advection rather than by radiation or condensation processes. In addition, the sea ice perturbations lead to changes in the hydrological cycle. Our results consequently imply that both temperature and snow accumulation records from Greenland ice cores are sensitive to sea ice changes in the Nordic Seas but insensitive to sea ice changes in the Labrador Sea. Moreover, the simulations suggest that the uncertainty in the Eemian sea ice cover accounts for 1.6 • C of the Eemian warming at the NEEM ice core site. The estimated Eemian warming of 5 • C above present day based on the NEEM δ 15 N record can be reconstructed by the CCSM4 model for the scenario of a substantial sea ice retreat in the Nordic Seas combined with a reduced Greenland ice sheet.

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“…It is also characterized by enhanced interhemispheric and seasonal contrasts (Nikolova et al, 2013). Large uncertainties also reside in the conversion of Greenland and Antarctic ice core water stable isotope records to temperature, with implications for assessing the vulnerability of ice sheets to local warming (Masson-Delmotte et al, 2011a;Sime et al, 2009Sime et al, , 2013NEEM community members, 2013). Climate models have been shown to underestimate the magnitude of Arctic warming and to fail capturing Antarctic temperature trends Bakker et al, 2014).…”

Section: Selection Of Target Periodsmentioning

confidence: 99%

Water and carbon stable isotope records from natural archives: a new database and interactive online platform for data browsing, visualizing and downloading

et al. 2016

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Abstract. Past climate is an important benchmark to assess the ability of climate models to simulate key processes and feedbacks. Numerous proxy records exist for stable isotopes of water and/or carbon, which are also implemented inside the components of a growing number of Earth system model. Model-data comparisons can help to constrain the uncertainties associated with transfer functions. This motivates the need of producing a comprehensive compilation of different proxy sources. We have put together a global database of proxy records of oxygen (δ 18 O), hydrogen (δD) and carbon (δ 13 C) stable isotopes from different archives: ocean and lake sediments, corals, ice cores, speleothems and tree-ring cellulose. Source records were obtained from the georeferenced open access PANGAEA and NOAA libraries, complemented by additional data obtained from a literature survey. About 3000 source records were screened for chronological information and temporal resolution of proxy records. Altogether, this database consists of hundreds of dated δ 18 O, δ 13 C and δD records in a standardized simple text format, complemented with a metadata Excel catalog. A quality control flag was implemented to describe age markers and inform on chronological uncertainty. This compilation effort highlights the need to homogenize and structure the format of datasets and chronological information as well as enhance the distribution of published datasets that are currently highly fragmented and scattered. We also provide an online portal based on the records included in this database with an intuitive and interactive platform (http://climateproxiesfinder.ipsl.fr/), allowing one to easily select, visualize and download subsets of the homogeneously formatted records that constitute this database, following a choice of search criteria, and to upload new datasets. In the last part, we illustrate the type of application allowed by our database by comparing several key periods highly investigated by the paleoclimate community.

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Warm climate isotopic simulations: what do we learn about interglacial signals in Greenland ice cores?

Cited by 50 publications

References 71 publications

The PMIP4 contribution to CMIP6 – Part 2: Two interglacials, scientific objective and experimental design for Holocene and Last Interglacial simulations

The PMIP4 contribution to CMIP6 – Part 2: Two interglacials, scientific objective and experimental design for Holocene and Last Interglacial simulations

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

Water and carbon stable isotope records from natural archives: a new database and interactive online platform for data browsing, visualizing and downloading

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