Sir Charles Lyell, 1st Baronet, FRS (14 November 1797 – 22 February 1875) was a Scottish geologist who demonstrated the power of known natural causes in explaining the earth's history. He is best known today for his association with Charles Darwin and as the author of Principles of Geology (1830–33), which presented to a wide public audience the idea that the earth was shaped by the same natural processes still in operation today, operating at similar intensities. The philosopher William Whewell dubbed this gradualistic view "uniformitarianism" and contrasted it with catastrophism, which had been championed by Georges Cuvier and was better accepted in Europe. The combination of evidence and eloquence in Principles convinced a wide range of readers of the significance of "deep time" for understanding the earth and environment.
Lyell's scientific contributions included a pioneering explanation of climate change, in which shifting boundaries between oceans and continents could be used to explain long-term variations in temperature and rainfall. Lyell also gave influential explanations of earthquakes and developed the theory of gradual "backed up-building" of volcanoes. In stratigraphy his division of the Tertiary period into the Pliocene, Miocene, and Eocene was highly influential. He incorrectly conjectured that icebergs were the impetus behind the transport of glacial erratics, and that silty loess deposits might have settled out of flood waters. His creation of a separate period for human history, entitled the 'Recent', is widely cited as providing the foundations for the modern discussion of the Anthropocene.