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Abstract: Rapid climatic changes, the rhythm of which is fully described in Greenland deep ice cores, are also very well documented in the ocean (in particular in the North Atlantic) and on the continent. At these timescales, ice cores, deep sea-cores and continental records are still difficult to precisely synchronize. From the GRIP results, we show how a multiparametric ice core study allows us to circumvent this difficulty. The co-isotopic analysis of the deuterium and oxygen-18 concentrations in ice gives access to temperature both at the site (central Greenland) and in the evaporative moisture source region (North Atlantic). Rapid changes occur more or less rapidly from one event to the next, but are generally simultaneous. Surprisingly, our results suggest that the site and source temperatures vary in antiphase. This implies a drastic reorganization of the hydrological cycle in the North Atlantic at the time of rapid changes. To cite this article: J. Jouzel et al., C. R. Geoscience 337 (2005). [Copyright &y& Elsevier]

Abstract: During the last glacial, characterized by a rapid climatic variability, the Greenland ice isotope–temperature relationship is biased due to changes in the hydrological cycle. An alternative palaeothermometry method, based on air isotopes, N and Ar, provides quantitative estimates of rapid temperature increases and suggests a different shape of rapid events compared to water isotope profiles. The temperature over five Dansgaard–Oeschger events (DO) on the NorthGRIP ice core is reconstructed: DO 18, 19, 20, 23 and 24 associated with warming events of 11, 16, 11, 10 and 16 °C, i.e. roughly twice larger than the amplitude suggested by the water isotopes. Together with similar efforts, our measurements permit to show a large variability between the different DO. To cite this article: A. Landais et al., C. R. Geoscience 337 (2005). [Copyright &y& Elsevier]