Rapid coupling between ice volume and polar temperature over the past 150,000 years

Abstract

Current global warming necessitates a detailed understanding of the relationships between climate and global ice volume. Highly resolved and continuous sea-level records are essential for quantifying ice-volume changes. However, an unbiased study of the timing of past ice-volume changes, relative to polar climate change, has so far been impossible because available sea-level records either were dated by using orbital tuning or ice-core timescales, or were discontinuous in time. Here we present an independent dating of a continuous, high-resolution sea-level record in millennial-scale detail throughout the past 150,000 years. We find that the timing of ice-volume fluctuations agrees well with that of variations in Antarctic climate and especially Greenland climate. Amplitudes of ice-volume fluctuations more closely match Antarctic (rather than Greenland) climate changes. Polar climate and ice-volume changes, and their rates of change, are found to covary within centennial response times. Finally, rates of sea-level rise reached at least 1.2 m per century during all major episodes of ice-volume reduction.

Stable isotope compositions of speleothems from the last interglacial – Spatial patterns of climate fluctuations in Europe

“…10). At the same time the Dead Sea had elevated water levels (Torfstein et al, 2015), in agreement with the humid climate inferred for the eastern Mediterranean and increased Nile floods, leading to the formation of sapropel S5 (Grant et al, 2012). For the period of 128 to 123 ka Milner et al (2012) have suggested pronounced seasonality with increased summer aridity and winter precipitation on the basis of acicular aragonite formation (indicating enhanced evaporation) in an otherwise aquatic phase of the Tenaghi Philippon peatland (NE Greece).…”

Differences between the last two glacial maxima and implications for ice-sheet, δ18O, and sea-level reconstructions

“…This is insufficient to explain the large LGM-to-PGM environmental contrast, so we conclude that sea level dropped much more during the LGM than in the PGM. (Grant et al, 2012); MS21 (32 20.7 0 N, 31 39.0 0 E, 1022 m water depth) (Hennekam, 2015); M40-67 (34.814167 N, 27.296000 E, water depth 2157 m), and M40-71 (34.811160 N, 23.194160 E, water depth 2788 m) (Weldeab et al, Fig. 1.…”

“…Near-continuous records can be evaluated probabilistically, accounting for both age uncertainties and sea-level uncertainties. These assessments identify probability maxima and their 95% probability bounds (Grant et al, 2012Rohling et al, 2014), which we use here. The two basins are independent; they are not connected, and link with separate oceans with different climate and ocean circulation dynamics (Schott et al, 2009;Buckley and Marshall, 2016).…”

“…PGM/MIS 6: Astakhov, 2011Astakhov et al, 2016;Ehlers et al, 2011a, b;Gurski et al, 1990;Mohr, 1993;Rose, 2009;Rose et al, 2002, Ruzicka, 2004Velichko et al, 2011. 2003a,b). d 18 O records include data for the surface-dwelling planktonic foraminifer Globigerinoides ruber (white) for all cores, and for the subsurface-dwelling planktonic foraminifer Neogloboquadrina pachyderma (dextral) for core LC21 (habitats after Rohling et al, 2004), and we use conversions to sea level after Rohling et al (2014) Grant et al, 2012;Hennekam, 2015), and recalibrating original 14 C datings with the most recent 14 C calibration curve (Reimer et al, 2013) using a DR value of 35 ± 70 years (Siani et al, 2000).…”

“…Such contrasting ice-mass distributions between successive glacial maxima highlight significant complexity in the processes that drive glaciation into different 'modes' (e.g., Liakka et al, 2016). The difference also has repercussions for glacioisostatic adjustment (GIA) studies of sea-level history during the LIG, which was about 1 C warmer than the Holocene (Clark and Huybers, 2009;Turney and Jones, 2010;McKay et al, 2011;Hoffman et al, 2017;Hansen et al, 2017), with sea levels that reached 4e10 m higher than today Dutton and Lambeck, 2012;Grant et al, 2012;Stocker et al, 2013;Dutton et al, 2015aDutton et al, , 2015b. Dendy et al (2017) investigated the sensitivity of the predictions of the last interglacial highstand to uncertainties in the configuration of the major northern hemisphere ice sheets during MIS 6.…”