Chapter summary

Long ice cores from Greenland and Antarctica and shorter cores from minor ice caps and glaciers have documented annual and decadal climate change during the last interglacial/ glacial cycle. The recent central Greenland ice cores (GRIP and GISP2) have clearly demonstrated the occurrence of large, rapid, regional to global climate oscillations during most of the last 110,000 years on a scale not recorded in modern times. Most of the glacial-interglacial changes occur over decades, while some indicators of atmospheric circulation change in only a few years. These millennial-scale events over Greenland were significant, with temperature fluctuations of up to 20°C, doubling of the snow accumulation, significant changes in wind-blown dust and sea-salt loading, and approximately lOOppbv variations in methane (CH4) concentrations. The recent central Greenland ice cores have given information about the origin of the ice sheet and its basal conditions, reconstruction of atmospheric circulation patterns and their temporal variations from chemical indicators and dust sources, and the anthropogenic influence on the chemical composition of the atmosphere. In addition, the cores have given data on glacier physics and flow modelling, solar influences on climate, and former size and atmospheric response of volcanic eruptions. In addition, the ice core from the Vostok station in East Antarctica has allowed the extension of the ice record of atmospheric composition and climate to the past four glacial-interglacial cycles.

This chapter also reviews how glacier-front variations are mapped and measured, and dating techniques used on terminal moraines and other deposits in glacier forelands, such as observation and measurements, historical documents, biological dating methods and physico-chemical techniques, are assessed. The use of lacustrine sediments and laminae/ varves to extract the (palaeo)climate signal is also discussed. Finally, the great potential of marine sediments in climate reconstruction is described.

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