NGRIP ice core reveals detailed climatic history 123 kyrs back in time

Pages News, Vol. 14, No. 1, pp 15-16, 2006
D. Dahl-Jensen
Ice and Climate, The Niels Bohr Institute, Juliane Maries Vej 30, DK-2100 Copenhagen, Denmark

In 2003, for the fi rst time, an undisturbed Greenland ice core record reaching further back than the glacial period was completed. The 3090 m long ice core from NGRIP, on the northern part of the Greenland Ice Sheet, contains layers of snowfall from the last 123,000 years. The annual layers close to the surface are 0.19 m thick, corresponding to the present accumulation rate (in ice equivalent) and the annual layers at the base are all around 1 cm thick. The basal annual layer thickness is so well preserved due to a basal melt of 7 mm/yr, reducing the thinning near the bed (Dahl-Jensen et al., 2003). This very high-resolution record contains 1490 m of ice from the present interglacial period (0-11,703 yr b2k (before AD 2000)), 1600 m of ice from the glacial period (11,703-115,000 yr b2k) and 90 m of ice from the last interglacial period, the Eemian climatic period (NGRIP members, 2004)