The chapter provides a brief summary of Earth's geological history, spanning from its origin to the Quaternary. It presents the main geological periods, key events and qualitative transitions in atmospheric composition, climate variability and the complex interaction between climate and life. It discusses the role of the Great Oxidation Event for climate and biosphere, the so-called “faint young sun paradox,” and the mechanisms behind the Neoproterozoic snowball Earth. The role of plate tectonics and the formation and collapse of supercontinents in climate history is described. The Paleocene and Eocene greenhouse climates and possible mechanisms of the Paleocene-Eocene Thermal Maximum are examined. The influence of a gradual Cenozoic cooling in the transition from a greenhouse to an icehouse world is explored alongside the leading hypothesis for the cause of Antarctic glaciation. Finally, the role of various factors in the transition to regular Quaternary glacial cycles is discussed.

The conditions on early Earth prior to four billion years ago (Hadean Earth), which shaped the origin(s) and early evolution of life, are discussed in this chapter. It begins with a summary of the various sources of internal heat on terrestrial planets and the types of heat transport (e.g., conduction), as these factors influenced the habitability of early Earth and its temporal evolution. This is followed by an exposition of the characteristics of Hadean Earth: the Moon-forming impact, oceans, landmasses, and atmosphere, including the faint young Sun paradox – how did Earth stay unfrozen despite the Sun’s lower luminosity? The chapter concludes with sketching the putative Late Heavy Bombardment (a potential spike in the impactor rate) about four billion years ago, and a general treatment of the positives and downsides of large impacts.