2021 Nobel Prize in Physics

Iacopo Russo reports on the winners of the 2021 Nobel Prize in Physics...

Iacopo - The Nobel Prize in Physics this year was all about the climate and other complex systems.

One half went to Syukuru Manabe and Klaus Hasselmann, for their contribution to the way we understand the Earth’s climate and its recent changes. We all know that the Earth is heating up because of carbon emissions, but it was thanks to Manabe’s models that we discovered the link between carbon dioxide concentration in the atmosphere and temperature. Very few people today would dispute that human activities are contributing to heating the planet’s atmosphere; well, Hasselmann was the first to establish that natural factors are not enough to explain global warming, and that humans are responsible, too. Overall, their work laid the foundations for all the models that are now helping us predict how a complex system like the climate will evolve in the next decades.

The other half of the prize, instead, went to Giorgio Parisi, for the theories he developed on disordered materials and random processes. Many problems in physics deal with systems made up of a lot of elements that interact with each other in random ways: the weather, for example, or the human brain, or even a flock of starlings. Parisi found a way to describe mathematically the hidden structure behind a complex system. His discoveries make it possible to understand and describe many different materials and phenomena that appear to be entirely random, not only in physics but also in other areas, such as mathematics, biology, neuroscience and machine learning.

The chair of the Nobel Committee for Physics highlighted how the discoveries recognised this year demonstrate that our knowledge about the climate rests on a solid scientific foundation, based on a rigorous analysis of observations. These scientists have helped us get a deeper insight into the properties and evolution of complex physical systems.