The Royal Swedish Academy of Sciences announced its decision, on October 5, 2021, to award the 2021 Nobel Prize in Physics to three Laureates for their studies of “chaotic and apparently random phenomena.” According to the official press release, two of this year’s recipients, Syukuro Manabe of Princeton University and Klaus Hasselmann of the Max Planck Institute of Meteorology “laid the foundation of our knowledge of the Earth’s climate and how humanity influences it.” The third recipient, Giorgio Parisi of Sapienza University of Rome, Italy, was lauded “for the discovery of the interplay of disorder and fluctuations in physical systems from atomic to planetary scales.”
Manabe was honored for demonstrating how increased levels of carbon dioxide in the atmosphere led to increased temperatures at the Earth’s surface. Early in his career, he helped develop physical models of the Earth’s climate and was the first to explore interactions between radiation balance and vertical transport of air masses, thus laying the foundation for today’s climate models.
Hasselmann created a model linking weather and climate that showed how climate models can be reliable despite weather being changeable and seemingly chaotic. He helped identify certain signals or “fingerprints” that natural and anthropogenic phenomena leave on the climate. His methods helped to prove that increasing temperatures in the atmosphere are the result of human emissions of carbon dioxide.
“The discoveries being recognized this year demonstrate that our knowledge about the climate rests on a solid scientific foundation, based on a rigorous analysis of observations. This year’s Laureates have all contributed to us gaining deeper insight into the properties and evolution of complex physical systems,” stated Thors Hans Hansson, chair of the Nobel Committee for Physics.