Klaus Ferdinand Hasselmann (Hamburg, 25 October 1931) is a German climatologist, physicist and meteorologist known for his pioneering studies on the use of computers for climate simulations. In 2021 he received the Nobel Prize in Physics (together with Syukuro Manabe and separately from Giorgio Parisi) "for the physical modeling of the Earth's climate, quantifying variability and reliably predicting global warming." In particular, it was the first assignment of this prize for topics related to climatology, and geophysics in general.
Hasselmann's father, Erwin (1903-1994), was an economist, journalist and editor, politically active for the Social Democratic Party of Germany (SPD) since 1920. Due to his father's activity in the SPD, the family emigrated to the Kingdom United in mid-1934 at the beginning of the Nazi era to escape repressive regime and persecution of the Social Democrats, and Klaus Hasselmann grew up in the UK from the age of two. They lived in Welwyn Garden City in north London and his father worked as a journalist in the UK. Although the Hasselmanns were not Jews, they lived in a close-knit community of mostly Jewish German immigrants and received assistance from English Quakers when they arrived in the country.
Klaus Hasselmann attended Elementary and Grammar School in Welwyn Garden City. Hasselmann said that "I felt very happy in England" and that English is his first language. His parents returned to Hamburg in 1948, but Klaus stayed in England to finish his studies. In August 1949, at the age of nearly eighteen, he too moved to Hamburg to attend higher education. After a practical mechanical engineering course from 1949 to 1950, he enrolled at the University of Hamburg in 1950 to study physics and mathematics.
Klaus Hasselmann has been married to Susanne Hasselmann (born Barthe) since 1957, also a meteorologist, with whom he has worked together several times. They have three children.
Academic career and research
Klaus Hasselmann graduated in physics and mathematics from the University of Hamburg in 1955 with a thesis on isotropic turbulence. He then obtained a doctorate in physics in 1957 from the University of Göttingen and the Max Planck Institute of Fluid Dynamics (today the Max Planck Institute for Dynamics and Self-Organization). His thesis concerned a method for determining the reflection and refraction of arbitrary small wavelength shock waves at the interface between two media. In 1963 he obtained the Habilitation. He was assistant professor at the University of Hamburg from 1957 to 1961, and then at the Scripps Institution of Oceanography at the University of California at San Diego. From 1966 he was then professor of geophysics at the University of Hamburg, with other short periods at the University of Cambridge and the Woods Hole Oceanographic Institution, and finally, from 1975 to 1999, director of the Max Planck Institute of Meteorology. published articles on climate dynamics, stochastic processes, sea waves, remote control and more. His fame in oceanography is mainly due to a group of articles concerning nonlinear interactions in sea waves, in which he adapted the formalism of Feynman diagrams to classical random waves. Later he realized that similar techniques were already used by plasma physicists, and that in fact he had rediscovered some of Rudolf Peierls' results concerning the diffusion of heat in solids by non-linear interactions between phonons. for introducing in 1976 a stochastic model known as the Hasselmann model, in which the random fluctuations of the climate are described by a Wiener process. In the study of global warming, he is the author who received the most citations for publication from 1991 to 2001. In pa