Book excerpt: The Earth's climate system depends entirely on the Sun for its energy. Solar radiation warms the atmosphere and is fundamental to atmospheric composition, while the distribution of solar heating across the planet produces global wind patterns and contributes to the formation of clouds, storms, and rainfall. The Sun’s Influence on Climate provides an unparalleled introduction to this vitally important relationship. This accessible primer covers the basic properties of the Earth’s climate system, the structure and behavior of the Sun, and the absorption of solar radiation in the atmosphere. It explains how solar activity varies and how these variations affect the Earth’s environment, from long-term paleoclimate effects to century timescales in the context of human-induced climate change, and from signals of the 11-year sunspot cycle to the impacts of solar emissions on space weather in our planet’s upper atmosphere. Written by two of the leading authorities on the subject, The Sun’s Influence on Climate is an essential primer for students and nonspecialists alike.