The North Atlantic Ocean during the last deglaciation

Ruddiman, William F.; McIntyre, Andrew

doi:10.1016/0031-0182(81)90097-3

Cited by 733 publications

(244 citation statements)

References 101 publications

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“…Ice sheet meltwater in the form of river runoff or icebergs has long been identified as a potential cause for ocean circulation changes (Ruddiman and McIntyre, 1981). Reconstructions of the deglacial drainage chronology and drainage locations (Tarasov and Peltier, 2006), and atmosphere-ocean model studies (Mikolajewicz et al, 1997;Roche et al, 2009;Liu et al, 2009;Okazaki et al, 2010;Menviel et al, 2011) suggested that meltwater from the Laurentide ice sheet led to reduced North Atlantic Deep Water formation after the LGM.…”

Section: Discussionmentioning

confidence: 99%

Deglacial ice sheet meltdown: orbital pacemaking and CO<sub>2</sub> effects

et al. 2014

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Abstract.One hundred thousand years of ice sheet buildup came to a rapid end ∼ 25-10 thousand years before present (ka BP), when ice sheets receded quickly and multi-proxy reconstructed global mean surface temperatures rose by ∼ 3-5 • C. It still remains unresolved whether insolation changes due to variations of earth's tilt and orbit were sufficient to terminate glacial conditions. Using a coupled three-dimensional climate-ice sheet model, we simulate the climate and Northern Hemisphere ice sheet evolution from 78 ka BP to 0 ka BP in good agreement with sea level and ice topography reconstructions. Based on this simulation and a series of deglacial sensitivity experiments with individually varying orbital parameters and prescribed CO 2 , we find that enhanced calving led to a slowdown of ice sheet growth as early as ∼ 8 ka prior to the Last Glacial Maximum (LGM). The glacial termination was then initiated by enhanced ablation due to increasing obliquity and precession, in agreement with the Milankovitch theory. However, our results also support the notion that the ∼ 100 ppmv rise of atmospheric CO 2 after ∼ 18 ka BP was a key contributor to the deglaciation. Without it, the presentday ice volume would be comparable to that of the LGM and global mean temperatures would be about 3 • C lower than today. We further demonstrate that neither orbital forcing nor rising CO 2 concentrations alone were sufficient to complete the deglaciation.

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Section: Discussionmentioning

confidence: 99%

Deglacial ice sheet meltdown: orbital pacemaking and CO<sub>2</sub> effects

et al. 2014

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“…It appears that the presence of Northern Hemisphere ice sheets and their influence on the North Atlantic ocean circulation results in greater cooling of winter temperatures during the last glacial. At that time, the polar front extended southwards, eventually reaching a latitude south of 40 o N on the Iberian coast at the LGM (Ruddiman and McIntye, 1981;Siani et al, 2001). Evidence for a southward movement of the polar front is also available from reconstructions of wind patterns in the Mediterranean (Florineth and Schlüchter, 2000).…”

Section: Past Seasonality In Sst At Gibraltarmentioning

confidence: 99%

Increased seasonality in the Western Mediterranean during the last glacial from limpet shell geochemistry

Ferguson

Henderson

et al. 2011

Earth and Planetary Science Letters

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Editor: P. DeMenocalKeywords: mollusc seasonality Gibraltar palaeoclimate oxygen isotopesThe seasonal cycle is a fundamental aspect of climate, with a significant influence on mean climate and on human societies. Assessing seasonality in different climate states is therefore important but, outside the tropics, very few palaeoclimate records with seasonal resolution exist and there are currently no glacial-age seasonal-resolution sea-surface-temperature (SST) records at mid to high latitudes. Here we show that both Mg/Ca and oxygen isotope (δ 18 O) ratios in modern limpet (Patella) shells record the seasonal range of SST in the western Mediterranean -a region particularly susceptible to seasonal change. Analysis of a suite of fossil limpet shells from Gibraltar shows that SST seasonality was greater during the last glacial by~2°C as a result of greater winter cooling. These extra-tropical seasonal-resolution SST records for the last glacial suggest that the presence of large ice-sheets in the northern hemisphere enhances winter cooling. This result also indicates that seasonality in the Mediterranean is not well-represented in most palaeoclimate models, which typically show little change in seasonal amplitude, and provides a new test for the accuracy of climate models.

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“…If the meltwater-productivity hypothesis of Ruddiman and McIntyre (1981b) is correct, then there should be a low salinity influence at some lower latitude with limited biogenic carbonate production. This is evident from their study of cores from the southern margin of the subpolar gyre (40"-45"N) where there apparently was phytoplankton productivity with insignificant zooplankton productivity.…”

Section: Sedimentationmentioning

confidence: 99%

High Resolution Isotope Study of the Latest Deglaciation Based on Bermuda Rise Cores

et al. 1984

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A stable isotope and 14C investigation of carbonates from three late Quaternary cores with high rates of sedimentation from the northeastern Bermuda Rise has produced the highest resolution record of the glacial maximum to Holocene stable isotope change yet obtained from an open ocean location. The record includes a three-step “termination” and the first direct evidence of an early deglacial meltwater “spike” in the open sea.

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The North Atlantic Ocean during the last deglaciation

Cited by 733 publications

References 101 publications

Deglacial ice sheet meltdown: orbital pacemaking and CO<sub>2</sub> effects

Deglacial ice sheet meltdown: orbital pacemaking and CO<sub>2</sub> effects

Increased seasonality in the Western Mediterranean during the last glacial from limpet shell geochemistry

High Resolution Isotope Study of the Latest Deglaciation Based on Bermuda Rise Cores

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The North Atlantic Ocean during the last deglaciation

Cited by 733 publications

References 101 publications

Deglacial ice sheet meltdown: orbital pacemaking and CO&lt;sub&gt;2&lt;/sub&gt; effects

Deglacial ice sheet meltdown: orbital pacemaking and CO&lt;sub&gt;2&lt;/sub&gt; effects

Increased seasonality in the Western Mediterranean during the last glacial from limpet shell geochemistry

High Resolution Isotope Study of the Latest Deglaciation Based on Bermuda Rise Cores

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Deglacial ice sheet meltdown: orbital pacemaking and CO<sub>2</sub> effects

Deglacial ice sheet meltdown: orbital pacemaking and CO<sub>2</sub> effects