Physics Nobel Prize 2021 for Klaus Hasselmann

Klaus Hasselmann and Syukuro Manabe are honoured for their fundamental contributions to climate research, Giogio Parisi for his research on disordered materials and random processes. Klaus Hasselmann developed a model of how weather and climate are connected, i.e. how short-term phenomena such as precipitation are related to long-term developments such as ocean currents. He thus provided evidence why climate models can deliver reliable predictions despite short-term weather fluctuations. In this way, he proved the connection between the increase in CO2 concentration in the atmosphere and global warming.

Klaus Hasselmann was Director at the Max Planck Institute for Meteorology in Hamburg from 1975 to November 1999 and Scientific Director at the German Climate Computing Centre from 1988 to 1999.

The 89-year-old investigated human-made climate change and the greenhouse effect early on. "In 30 to 100 years, depending on how much fossil fuel we consume, we will face a very significant climate change. Climate zones will shift, precipitation will be distributed differently. Then we will no longer be able to talk about random results," he said in a 1988 interview. "We should realise that we are entering a situation where there is no turning back."

The emeritus director at the MPI for Meteorology developed a model that links weather and climate and thus answers the question of why climate models can be reliable despite changeable and chaotic weather. He also developed methods to identify specific signals that both natural phenomena and human activities leave on the climate. With his methods, he was able to prove that the rise in temperature in the atmosphere is due to carbon dioxide emissions by humans.

Nobel Prize in Physics for the second time in a row

Already last year, a Max Planck scientist was honoured with the highest scientific award in physics. Reinhard Genzel, Director at the Max Planck Institute for Extraterrestrial Physics in Garching, received the Nobel Prize in Physics 2020 together with Roger Penrose and Andrea Ghez. The Royal Swedish Academy honoured the scientists for their research on black holes.

As in the previous year, the Nobel Prizes are endowed with ten million Swedish kronor (about 980,000 euros) per category. The prestigious Nobel medals and diplomas are traditionally awarded on 10 December, the anniversary of the death of prize donor and dynamite inventor Alfred Nobel.

Text by the Max Planck Society

Nobel Prize in Physics for Prof. Klaus Hasselmann - a look back to the future
A summary by Michael Böttinger, DKRZ