ABSTRACT
Atmospheric conditions vary on all time scales from day-to-day weather fluctuations to climatic changes spanning millennia. The various fluctuations and changes are superimposed upon each other to give the complex time sequence of past climates. The field of palaeoclimatology is the study of these sequences, and is dedicated to defining and explaining the evolution of climate. While there is an intrinsic interest in this, and while knowledge of past climates can have an important bearing on other branches of knowledge, we are particularly concerned here with those aspects which permit us to understand present atmospheric processes, and which can be used to test models and provide clues to future conditions. Palaeoclimatology requires a highly interdisciplinary approach. Geologists, oceanographers, glaciologists, botanists, archaeologists and historians, among others, are all involved with climatologists in unravelling the patterns of past climates. The techniques used are equally varied. Consequently this chapter can be only an overview, and is divided into three main portions: a description of methods for revealing past climates; a review of results from these methods; and an examination of causes of climatic change.
