Abstract: The 2021 Nobel Prize in Physics was awarded to two climate scientists and one theoretical physicist for their groundbreaking work on our understanding of complex physical systems. Here the major work of one of them, Syukuro Manabe, is introduced. As a complex system, the global climate system exhibits high complexity. Manabe’s radiative-convective equilibrium model, as an approximation to this system, for the first time reliably quantifies the warming magnitude (2.36 ℃ ) induced by the doubling of CO₂. He is also named the father of global climate models, which have become an indispensable tool for our mechanistic understanding of global climate change and for the projection of future climate change. The basic idea of the radiative-convective equilibrium model as well as its recent development and remaining issues are introduced. The components of the global climate model are also briefly described with an emphasis on the physical basis and remaining challenges. Future directions and trends of climate model studies and development are discussed.