RT Journal Article
T1 Heinrich event 1: an example of dynamical ice-sheet reaction to oceanic changes
A1 Álvarez Solas, Jorge
A1 Montoya Redondo, María Luisa
A1 Ritz, C.
A1 Ramstein, G.
A1 Charbit, S.
A1 Dumas, C.
A1 Nisancioglu, K.
A1 Dokken, T.
A1 Ganopolski, A.
AB Heinrich events, identified as enhanced ice-rafted detritus (IRD) in North Atlantic deep sea sediments (Heinrich, 1988; Hemming, 2004) have classically been attributed to Laurentide ice-sheet (LIS) instabilities (MacAyeal, 1993; Calov et al., 2002; Hulbe et al., 2004) and assumed to lead to important disruptions of the Atlantic meridional overturning circulation (AMOC) and North Atlantic deep water (NADW) formation. However, recent paleoclimate data have revealed that most of these events probably occurred after the AMOC had already slowed down or/and NADW largely collapsed, within about a thousand years (Hall et al., 2006; Hemming, 2004; Jonkers et al., 2010; Roche et al., 2004), implying that the initial AMOC reduction could not have been caused by the Heinrich events themselves. Here we propose an alternative driving mechanism, specifically for Heinrich event 1 (H1; 18 to 15 ka BP), by which North Atlantic ocean circulation changes are found to have strong impacts on LIS dynamics. By combining simulations with a coupled climate model and a three-dimensional ice sheet model, our study illustrates how reduced NADW and AMOC weakening lead to a subsurface warming in the Nordic and Labrador Seas resulting in rapid melting of the Hudson Strait and Labrador ice shelves. Lack of buttressing by the ice shelves implies a substantial ice-stream acceleration, enhanced ice-discharge and sea level rise, with peak values 500-1500 yr after the initial AMOC reduction. Our scenario modifies the previous paradigm of H1 by solving the paradox of its occurrence during a cold surface period, and highlights the importance of taking into account the effects of oceanic circulation on ice-sheets dynamics in order to elucidate the triggering mechanism of Heinrich events.
PB Copernicus Gesellschaft MBH
SN 1814-9324
YR 2011
FD 2011-11-29
LK https://hdl.handle.net/20.500.14352/44086
UL https://hdl.handle.net/20.500.14352/44086
LA eng
NO We thank Y. Donnadieu, D. Paillard, D. Roche, F. Remy, F. Pattyn, A. Robinson and E. Lucio for helpful discussions, and two anonymous referees and the editor Andre Paul who helped to improve the manuscript. Figure 5 of this article is based on a similar figure suggested by referee #2. We are also greatful to the PalMA group for useful comments and suggestions. This work was funded under the MOVAC and SPECT-MORE projects. J. A-S was also funded by the Spanish programme of the International Campus of Excellence (CEI).
NO MOVAC
NO SPECT-MORE
NO Spanish programme of the International Campus of Excellence (CEI)
DS Docta Complutense
RD 28 abr 2025