5. Palaeo-Climate Change

5.1. Introduction

Chapter 5 is a review of the major episodes of climate change that have occurred through Earth history, prior to the advent of the use of instrumental data. Although the contemporary climate change record spans only a tiny fraction (10^-7) of Earth history, in light of its current and future implications to the global society, it forms the basis of a separate chapter (chapter 6).

This chapter begins with a discussion of climate changes over the longest time scales (10⁶ to 10⁸ years), those associated with continental drift, followed by an investigation into the Quaternary glacials (last 2 Ma), assumed to be driven by orbital forcing mechanisms (see chapter 2). Finally, century and millennia time scales of climate change over the last 10,000 years will be reviewed. For all sections, the evidence for climate change will be drawn from both empirical investigations (see chapter 3) and modelling studies (see chapter 4).