Quaternary Science Reviews 21 (2002) 343–360 Into and out of the Last Glacial Maximum: sea-level change during Oxygen Isotope Stages 3 and 2 Kurt Lambeck a, *, Yusuke Yokoyama b,c , Tony Purcell a a Research School of Earth Sciences, Australian National University, Canberra, ACT 0200, Australia b Space Sciences Laboratory, University of California, Berkeley, CA, USA c Lawrence Livermore National Laboratory, Livermore, CA, USA Received 11 January 2001; accepted 18 May 2001 Abstract Sea-level data from seven different regions have been used to estimate the global change in ocean and ice volumes for the time interval leading into and out of the Last Glacial Maximum (LGM). The estimates are earth-model dependent and parameters are chosen that minimize discrepancies between the individual estimates for each region. Good coherence between estimates from different localities has been found. The main conclusions are: (i) Ice volumes approached their maximum values 30 000 (calendar) years ago and remained nearly constant until 19 000 years ago. This defines the period of maximum global glaciation. (ii) The post- LGM sea-level rise is marked by changes in rates with maximum rates of about 15 mm/year occurring from 16,000 to 12,500 years ago and again from 11,500 to 9000 years ago. Ice volumes in the interval between these two periods of rapid rise, corresponding to the Younger Dryas, is nearly constant. (iii) The melting at the end of the LGM is characterized by an initially high rate over about 500 years followed by about 2500 years of a comparatively slow increase in ocean volume. (iv) The lead into the LGM is characterized by a sea-level fall of about 50 m occurring within a few thousand years. Similar rates of falling and rising sea levels occur during the earlier part of the oxygen isotope stage 3 interval. r 2001 Elsevier Science Ltd. All rights reserved. 1. Introduction During the Last Glacial Maximum (LGM) large ice sheets covered high latitude Europe and North America and the Antarctic ice sheet was more extensive than today. Sea levels stood some 120–130 m lower than today. The Earth’s climate at this time was also distinctly different from that of the present interglacial conditions. The sea-level changes are indicators of growth and decay of ice sheets and provide, thereby, boundary conditions on models of climate change. Aspects of the sea-level change that are particularly relevant to understanding climate change and the response of the ice sheets to this change are (i) the timing of the onset and termination of the low stands that mark the LGM and (ii) the determination of the rates of sea-level rise or fall leading into and out of the LGM. Sea-level change caused by the growth or decay of ice sheets is spatially variable because of the adjustment of the earth’s surface to the time-dependent ice-water load and because of the changing gravitational potential of the earth-ocean-ice system. Observations of relative sea- level change, therefore, do not bear a simple relation to changes in ice volume, (or ice-equivalent sea level) and at most localities corrections for glacio-hydro-isostasy will be required. Even sea levels at ocean island sites are not immune from isostatic effects. Only in some special instances, where the separate isostatic responses to the changing water and ice loads fortuitously cancel out, will the relationship be relatively straight forward. Thus, in general, changes in ocean volume inferred from sea level data will be dependent on the models of glacio- hydro-isostasy and be functions of the spatial and temporal distribution of the ice load and of the rheological response of the Earth to surface loading. However, through an iterative approach, useful esti- mates of grounded and land-based ice volumes can be inferred from sea-level information, particularly when the data are from sites that lie far from the former ice *Corresponding author. Tel.: +61-2-6249-5161; fax: +61-2-6249- 5443. E-mail address: kurt.lambeck@anu.edu.au (K. Lambeck). 0277-3791/02/$ - see front matter r 2001 Elsevier Science Ltd. All rights reserved. PII:S0277-3791(01)00071-3