Encyclopedia of Climate System Science provides authoritative, up-to-date information on the observing, functioning, modeling, and projected future states of the Climate System. With contributions from hundreds of experts in the field, it is the most complete go-to reference for those interested in a discriminating understanding of climate variability and change. The Climate System is complex, consisting of myriad interactions and feedbacks within and across oceans, atmosphere, land surface, cryosphere, and biosphere, which lead to natural variability on timescales ranging from sub-seasonal to multidecadal. Superposed on the natural variations is Climate Change – a raging concern that has generated widespread interest in several facets of climate science. This encyclopedia highlights system interactions that play a leading role in shaping climate variability, their modulation by climate change, the multivariate structure of climate change in each subsystem, the extraction of this signal, and the robustness of climate projections. The Encyclopedia content is a balanced blend of observational analysis, theory, and numerical modeling. Its discussion of climate change is presented against a historically expansive backdrop populated by paleoclimates and the Anthropocene. This unique Encyclopedia provides readers with the knowledge framework for interpreting 20th-21st century climate variations and assessing 21st-22nd century climate projections. - With 7 sections and 400 chapters, this is a unique offering on the market: no other MRW presents Climate as a System Science, despite pervasive protestations that climate must be so viewed. - Serves a wide audience, focusing on the influential interactions between oceans, atmosphere, land surface, cryosphere, and biosphere. - Hugely topical area, given the level of international government pledges made at COP 26 to address climate change. - Provides an authoritative and unbiased account of the climate system, giving readers the framework needed to navigate through the information overload on climate and climate change. - Structured chapters, with extensive references and visual representations, help readers navigating the breadth of the topics; includes a Foreword from Nobel Laureate Sykuro Manabe (Princeton, Physics Nobel 2021), former teacher and research group leader of the Editor in Chief.