Klaus Hasselmann (Hamburg, Germany; 1931) earned his PhD in Physics in 1957 from the University of Göttingen and the Max Planck Institute of Fluid Dynamics. From 1961 to 1972, he carried out research at the University of Hamburg and, in the United States, at the Scripps Institution of Oceanography and the Woods Hole Oceanographic Laboratory. From 1988 to 1999, he was Scientific Director at the German Climate Computer Center in Hamburg.
Hasselmann is currently Emeritus Director of the Max Planck Institute for Meteorology in Hamburg (Germany), which he founded in 1975 and led for 25 years. He is also a founding member of the European Climate Forum, promoting multidisciplinary research on climate change.
His distinctions include the James B. Macelwane Award of the American Geophysical Union (1964), the Academic Award for Physics from the Academy of Sciences in Göttingen (1970), the Robertson Memorial Lecture Award of the U.S. National Academy of Sciences (1990), the Symons Memorial Medal of the UK’s Royal Meteorological Society (1997) and the Vilhelm Bjerknes Medal of the European Geophysical Society (2002). Since receiving the BBVA Foundation Frontiers of Knowledge Award (2009), he has gone on to win the Nobel Prize in Physics jointly with Syukuro Manabe and Giorgio Parisi (2021).
Speech
Climate Change, 2nd edition
“Scientific truth will always find a way,” is the credo of Klaus Hasselmann, Frontiers of Knowledge laureate in Climate Change. He is thinking here of the bleak years of climate change research, back in the 1990s, when vocal social groups denied the existence of climate change just as a majority of scientists were calling for more efforts to combat its effects. Hasselmann, currently Professor Emeritus at the Max Planck Institute for Meteorology in Hamburg, is a key figure in the recent history of climate studies. Not only did he construct the first models to simulate its progress, he also developed the techniques needed to identify the “human imprint” on today’s climate. It was these mathematical methods which proved that climate change was mainly attributable to human activity.
“Scientific truth will always find a way.”
TUITEAR
Hasselmann’s achievements were foreshadowed in his ambitions as a young researcher: “I wanted to work in an area where I could contribute something, where there were problems I felt able to solve.” How does a scientist acquire the experience and drive to “solve” climate change? In Hasselmann’s case, the first scientific challenge took the form of a crystal radio set. “Someone gave me one of those wireless sets, and I was fascinated by the fact that you could hear the radio without electrical power. It was a real mystery to me, so I went down to the local library and set to work studying electricity, magnetism, radio waves, etc. I was fourteen years old, my physics teacher considered me dead wood, and I never realized that what I was learning on my own and what was taught in class were actually the same thing. I started to build magnets and circuits and plug them into the mains, with the result that the fuses blew. The electrician complained to my parents. So basically I learned fast that I was not a great experimentalist and decided to concentrate on theory.”
After a childhood spent in England, where his parents had fled to escape the Nazi regime, Hasselmann returned to Germany with his family in 1949 and began studying physics and mathematics at Hamburg University. He specialized in fluid dynamics, determined to get to grips with turbulence, one of the legendary unknowns in physics. “Of course I didn’t solve the problem, but I used the theory of turbulence to derive a method for studying the formation and development of ocean waves,” he explains.
In 1961, this work took him to the Scripps Institution of Oceanography at the University of California in San Diego (United States) and subsequently to the Woods Hole Oceanographic Institute (Massachusetts, United States). Hasselmann was by that time an established oceanographer, designing and taking part in international expeditions to gather wave motion data in various world oceans. His work eventually led to the mathematical model that is currently used – in its improved form – by some 200 institutions worldwide to draw up their daily wave forecasts for shipping routes and coastal waters.
In 1972, partly by chance, Hasselmann moved into the climate field. “While I was at Woods Hole, I was invited to sit as an oceanographer on the organizing committee of the World Climate Research Program. The rest were meteorologists, and they needed an oceanographer on board. By then it was clear that we had a problem with climate; our job was to define what that problem was. It was a fascinating time.” Soon afterwards, an invitation came from the Max Planck Society to form a climate research institute.
The new center opened in 1975 and Hasselmann got to work straight away on setting up a climate model research program with young students. “The models then available did not include the oceans; we were the first to develop models that did. We were also the first to factor in the carbon cycle. They were pretty crude models too, with a resolution of barely 200 kilometers, a lot less than we can do today” he recalls, “but the order of magnitude was correct.”
Chance also played an important part in one of Hasselmann’s most high-impact achievements – his development of the mathematical technique known as fingerprinting, with power to reliably identify the human imprint in climate change. “Basically I developed the technique because I was giving a talk to a group of physicists on the climate problem and the doubts we had, when one of them suggested that we calculate the probability of the observed changes having a natural cause. We did it as an exercise, and it turned out that the probability was very small indeed. The media took up the story, and it has turned out to be immensely useful. But for me it was not conclusive proof that global warming was real, for the simple reason that we had that proof before.”
It was thanks to this technique that the United Nations Intergovernmental Panel on Climate Change (IPCC) could commit to paper in its 4th report, in 2007, that climate change was attributable to human factors.
Hasselmann has led the Max Planck Institute for Meteorology over a period of 25 years. Although he has not fulfilled his youthful ambition to “solve” the problem before him – climate change – he has never stopped thinking up ways to do so. In 2001, he founded the European Climate Forum (ECF) bringing together seven prestigious research centers, including ETH Zurich, the Potsdam Institute for Climate Impact Research (PIK) and the Tyndall Centre, as a platform for dialogue and joint working between scientists, industry and a wide range of social agents, from NGOs to political leaders.
On one point, Hasselmann is adamant. Economic analyses that factor in all the costs of climate change – including the cost of inaction – suggest the phenomenon can be seen as an opportunity: “The technology is there, and if we invest in it wisely, we can fight climate change without major changes in our way of life. Paradoxically, the main problem is that neither politicians nor the public are aware that this is a problem we can solve.”
