Paleoceanography and paleoclimatology: an Earth system perspective

The purpose of this paper is to provide an overview of paleoceanography and paleoclimatology as a framework for other papers dealing with The Earth System: Geochemical Perspectives. An introduction to both paleoceanography and paleoclimatology is followed by examples of the temporal changes through the Phanerozoic. The important and interactive role of the biosphere is emphasized. Many important changes in the Earth system have affected the coupled ocean–atmosphere system and many, in turn, have been reflected in biotic events. Many such changes can be tracked through time using geochemical signatures as proxy indicators. Whereas the scale of past paleoceanographic and paleoclimatic changes have been generally appreciated for some time, the recognition of periodic rapid change in the ocean/climate state and the ability to study and measure these precisely is only a recent accomplishment. The potential for such rapid change in the ocean/climate/biosphere of the Earth system raises concerns for events in the near future that may be forced by anthropogenic activities that enhance natural variability.