Physics Nobel awarded for work on chaotic systems such as the climate

Syukuro Manabe, Klaus Hasselmann and Giorgio Parisi Niklas Elmehed / Nobel Prize Outreach
Three researchers have been awarded the 2021 Nobel Prize in Physics for their groundbreaking discoveries regarding complex physical systems, such as weather, and climate change.

Syukuro Hasselmann at Princeton University was jointly awarded the Nobel. Klaus Hasselmann was previously at the Max Planck Institute for Meteorology, Hamburg, Germany. Klaus Hasselmann received the Nobel for his work in developing physical models of Earth's climate. These models helped to predict global warming reliably and show that human actions can have an effect on it.

Half of the award was given to Giorgio Parisi, Sapienza University in Rome, Italy for his discoveries about chaotic systems, such as how disorder, tiny fluctuations, and interplay on atomic to planet scales.


Both of these discoveries concern chaotic systems, which can be hard to mathematically describe due to large numbers of variables and large deviations in the results from small input changes. The Nobel Committee for Physics said that the winners contributed to better understanding such systems and their long-term evolution.

Thors Hans Hansson was the chair of the committee. He stated that, although the prizes were distinct, there was a common theme. It had to do both with disorder and with fluctuations. If you understand this properly, it can lead to something we can comprehend.

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In the 1960s Manabe was responsible for the creation of physical models of Earth's climate. He specialized in studying the interaction of heat from the sun and heat that is emitted via reflected radiation. His work was the basis for climate models that were used to predict the severity of climate change in various scenarios.

Hasselmann built a model based on his work ten years later that linked climate and weather. His methods were used to prove that human carbon dioxide emissions are responsible for the rising temperature of the atmosphere.

Parisi was awarded the other half of this prize for his spin-glass research. Any metal alloy where the magnetic field of one element changes in a chaotic fashion, such as iron and copper, is considered an unusual material. His understanding of these complex systems was useful for studying many other systems, such as weather and climate.

Parisi stated that countries must work fast to reduce the impact of climate change ahead of the COP26 summit in June. He stated that it was clear that future generations need to take action now and do so quickly. Positive feedback could be a positive factor that may help accelerate the temperature rise.