On the one hand, Syukuro Manabe from Princeton University (USA) and Klaus Hasselmann, from the Max Planck Institute for Meteorology in Hamburg (Germany) have been awarded for their contributions to the study of the earth’s climate. Manabe and Hasselmann crucially contributed to the development of complex models of climate dynamics, key for the understanding of the earth’s complex climate system. On the other hand, Giorgio Parisi, from Sapienza Univerity in Rome (Itlay), received the prize as a recognition to his contributions to the study of disordered systems at different scales, providing a series of conceptual tools nowadays crucial to understand the properties of a huge amount of disparate systems, ranging from biology to materials science.
See the official press note here:
https://www.nobelprize.org/prizes/physics/2021/press-release/