Physical Society/MSPS Colloquium

The 2021 Physics Nobel: “Complex systems”: The climate, with a geocomplexity update

Shaun Lovejoy

Department of Physics
McGill University

This year’s Physics prize was awarded to three scientists: two from climate science: Syukoro Manabe and Klauss Hasselmann, and one statistical physicist, Giorgio Parisi specializing in spin glasses. The climate scientists shared one half, Parisi the other half.

Manabe was honoured for pioneering numerical global circulation models (GCMs) in the 1960’s and 1970’s. Today GCMs are the main tool for modelling and projecting the earth’s climate. Hasselmann was also honoured mainly for work in the 1960’s and 70’s proposing a stochastic (statistical) model for explaining the climate as a slowly varying state driven by random weather noise.

The Nobel committee honoured contributions made on the eve of the Nonlinear revolution (especially in chaos and fractals), that later spawned nonlinear geophysics (1980’s) and geocomplexity (2000’s). In an update, I describe how these new fields made major improvements to the pioneer’s original picture. This includes an important Parisi contribution on scaling and multifractals and new developments on fractional generalizations of energy balance models.