Complex and yet predictable: The message of the 2021 Nobel Prize in Physics

Abstract

Syukuro (Suki) Manabe, Klaus Hasselmann, and Georgio Parisi were awarded the 2021 Nobel Prize in Physics. At first blush, this prize appears to recognize unrelated work in disparate fields. Even one of the Nobel Committee members acknowledged in the postannouncement press conference that it looks like a “split prize.” Upon reflection, however, there is a common thread running through the works of the awardees. Simply put, this year’s prize in physics acknowledges that disordered systems are predictable and that systems that behave chaotically can respond predictably to changes in external parameters. Earth’s climate is one such complex system, and it is of great importance to humanity. Its future must be predicted to guide policy. The prize also acknowledges that changes in the climate, like the properties of disordered condensed matter, are predictable using methods grounded in sound physics. Therefore, it is very appropriate to jointly recognize the foundational work done by these three visionary researchers with the Nobel Prize in Physics. This Nobel Prize in Physics is very different from the earlier Nobel Peace Prize awarded in 2007 to former Vice President Al Gore and the Intergovernmental Panel on Climate Change (IPCC), which recognized the importance of human-induced climate change and the actions needed to understand and mitigate it. It is also different from the 1995 Nobel Prize in Chemistry to Profs. Rowland, Molina, and Crutzen for their work on a global environmental problem arising from ozone depletion by manufactured chemicals, some of which were also major greenhouse gases. In contrast to those two earlier awards, the 2021 Nobel Prize in Physics recognizes the fundamental scientific basis of climate predictability, detection of change due to known external forcings, and the predictability of disordered condensed matter. Syukuro Manabe. Image credit: Denise Applewhite (Princeton University, Princeton, NJ). Climate scientists Syukuro Manabe and … [↵][1]1To whom correspondence may be addressed. Email: a.r.ravishankara{at}colostate.edu. [1]: #xref-corresp-1-1