Issue #80: The second Nobel year in the time of COVID-19: Physics

Written by Nobel Laureate Professor Peter Doherty

On Tuesday, 5 October, the 2021 Nobel Laureates for Physics were named by Göran Hansson, Secretary General of the Royal Swedish Academy of Sciences (RSAS). The next day, Goran Hansson announced the decision for Chemistry, then Economics on the following Monday. These three awards are selected by separate committees of the RSAS. The case for giving a Nobel Prize to the chosen candidates is then reviewed by ‘classes’ of RSAS members in the different disciplines, with the final approval depending on a vote by members of the full body of the RSAS who attend on the morning that the particular award is announced.

Participating in a scientific symposium (on climate change and sustainability) at the RSAS some 10 years back, we sat in the elegant, wood-panelled room (from 1915) where the RSAS members normally meet. Maybe it’s a false memory, but I seem to recall there were small pieces of paper where ‘yes’ or ‘no’ could be marked off. The mechanism used for voting in that older National Academy of Science, the Royal Society of London (founded in 1660 versus 1739 for the RSAS) is to use black or white balls, which is where the term ‘blackballed’ comes from.

Taking directly from the official announcement, the 2021 Nobel Prize for Physics was "for ground-breaking contributions to our understanding of complex systems" with one half jointly to Syukuro Manabe and Klaus Hasselmann "for the physical modelling of Earth's climate, quantifying variability and reliably predicting global warming" and the other half to Giorgio Parisi "for the discovery of the interplay of disorder and fluctuations in physical systems from atomic to planetary scales”. Goran Hansson then introduced the Chair of the RSAS physics selection committee Thor Hans Hansson, who pointed out that while many of us might think that physics is all about simple and ordered systems, like the earth’s elliptical orbit around the sun or the flow of electricity to our refrigerator, much of the effort in physics is concerned with using basic theories of matter to ‘interrogate’ and explain complex systems. Prominent in this type of analysis is the mathematical ingenuity that we all associate with climate models

Following the two Hanssons, co-opted (for this year’s award) committee member and climate scientist, John Wetlaufer spoke further about the awards. He summarised that, while the two climate scientists, Manabe and Hasselman, were looking outward to try to understand the complexities of climate, Parisi evidently ‘peered inward with mathematics’ as he sought to understand the properties of a rapidly cooled liquid (molten glass). The atoms of the glass we see through, or drink from, have evidently cooled to form a disordered (or ‘amorphous’) state that, so far as its ‘energy landscape’ is concerned, is permanently ‘frustrated’. The mathematical tools Parisi developed have evidently proved invaluable for others as they sought to add a ‘micro’ dimension that informs our understanding of the underlying ‘chaos’ that influences ‘macro’ scale systems, like climate.

Are you struggling with the preceding? I certainly did, but perhaps some of the journalists in the RSAS press room where the announcement was made may, if they were accustomed to writing about physics, have found the language more familiar. What was easy to follow was the historical timeline underlying the award to the two climate modelers. Back in 1824, Joseph Fourier evidently realised that the light from the sun was, when converted to ‘dark heat’ (later characterised by spectral analysis as infrared radiation) warming the earth. Then, 70 years later, Swedish physicist Svante Arrhenius calculated how progressive increases in atmospheric CO2 levels contribute to global warming as a consequence of the greenhouse effect that traps long wavelength infrared radiation. According to Arrhenius, doubling the amount of CO2 in the upper atmosphere would result in a 2o C rise in global mean temperature, the situation we are currently trying to avoid.

Arrhenius was a member of the RASA, and the first Swede to (in 1903) to be named as a Chemistry Nobelist. After a further 70 years, current physics laureate and meteorologist Syukuro Manabe showed formally how increased levels of CO2 in the atmosphere lead to higher temperatures at the surface of the Earth. Then, as the first person to explore the interaction between radiation balance and the vertical transport of air masses, he developed the mathematical tools that provided the basis for modelling climate systems.

Following on from Manabe’s work, Klaus Hasselman linked weather and climate to show how, despite weather being chaotic, it is possible to both model climate effectively and to input contemporary data that informs this analysis. Such linked timelines, in this case 70+70, sometimes emerge (are they deliberate?) for Nobel awards.

The global press corps that listens intensely as the Nobel announcements are made would, back in 1909, have rushed to the local telegraph station to report that the Physics Prize had been awarded to Gugielmo Marconi and Ferdinand Braun "in recognition of their contributions to the development of wireless telegraphy". Exactly 100 years later (2009) Charles Kao was named "for ground-breaking achievements concerning the transmission of light in fibres for optical communication", along with Willard S. Boyle and George E. Smith "for the invention of an imaging semiconductor circuit - the CCD sensor", technologies that today allow anyone across the planet to view the proceedings directly. To be continued…