Perspective on measurements and modeling of Earth’s climate

This paper celebrates the achievements in the modeling of the Earth’s atmosphere, ocean, and land that led to the discovery of anthropogenic climate change and, ultimately, to the awarding of the 2021 Nobel Prize in Physics to Syukuro Manabe and Klaus Hasselmann. The paper will succinctly recap its history, from the first pioneering years of Tyndall and Arrhenius, to the introduction of computers, to the latest breakthroughs and refinements. It will connect the work of modelists, who strive to create ‘digital twins’ of our planet in order to simulate its hydro-dynamical, chemical, and physical evolution through computerized models, and the observations needed to initialize the models themselves and validate them through comparisons and reanalysis, bridging the delicate gap between theory and measurements. Finally, we will present an overview of the future direction of this field of research, trying to highlight the challenges but also the opportunities and the importance of understanding the evolution of the Earth, especially for thermal-related quantities.