Klaus Hasselmann facts for kids

Klaus Ferdinand Hasselmann (born 25 October 1931) is a German scientist. He is an oceanographer, someone who studies the ocean. He also creates mathematical models to understand Earth's climate. He used to be a professor at the University of Hamburg. He was also the director of the Max Planck Institute for Meteorology. In 2021, he won the Nobel Prize in Physics. He shared this award with Syukuro Manabe and Giorgio Parisi.

Hasselmann grew up in Welwyn Garden City, England. He moved back to Hamburg, Germany, in 1949 for university. During his career, he mostly worked at the University of Hamburg. He also worked at the Max Planck Institute for Meteorology, which he helped start. He spent five years in the United States as a professor. He taught at the Scripps Institution of Oceanography and the Woods Hole Oceanographic Institution. He also spent a year as a visiting professor at the University of Cambridge.

He is famous for creating the Hasselmann model. This model helps explain how the climate changes. It shows how the ocean, which "remembers" past conditions, reacts to random pushes. These pushes come from things like weather patterns. This helps explain why climate changes often look like a "red-noise" signal. This means changes happen slowly over time, not suddenly.

Early Life and Education

Klaus Hasselmann was born in Hamburg, Germany. His father, Erwin Hasselmann, was an economist and journalist. He was active in politics with the Social Democratic Party of Germany. Because of his father's political work, the family moved to the United Kingdom in 1934. They wanted to escape the harsh rule of the Nazi era. Klaus grew up in the U.K. from age two.

They lived in Welwyn Garden City, north of London. His father worked as a journalist there. Even though the Hasselmanns were not Jewish, they lived in a community of German immigrants. Many of these immigrants were Jewish. The English Quakers helped them when they first arrived. Klaus went to elementary and grammar school in Welwyn Garden City. He finished his A-levels (high school exams) in 1949.

Hasselmann has said he "felt very happy in England." He also said English is his first language. His parents went back to Hamburg in 1948. But Klaus stayed in England to finish his studies. In August 1949, when he was almost eighteen, he joined his parents in Hamburg. He wanted to go to university there. He studied mechanical engineering for a year. Then, in 1950, he started studying physics and mathematics at the University of Hamburg.

Klaus Hasselmann married Susanne Barthe, a mathematician, in 1957. They also worked together professionally. His wife was a senior scientist at the Max Planck Institute for Meteorology. They have three children.

Professional Career and Climate Research

Cover image of the Ph.D. dissertation of Klaus Hasselmann defended in 1957 at the University of Göttingen

Hasselmann finished his physics and mathematics degree at the University of Hamburg in 1955. His thesis was about how fluids move in a swirling way. He then earned his PhD in physics from the University of Göttingen in 1957. His PhD work was about how shock waves and small waves reflect and bend when they hit a boundary between two different materials. In 1963, he completed his Habilitation, which allowed him to teach as a full professor.

He worked as an assistant professor at the University of Hamburg from 1957 to 1961. Then he became an assistant and associate professor at the Scripps Institution of Oceanography in La Jolla, California. He worked there from 1961 to 1964. In 1966, he became a Professor of Geophysics and Planetary Physics at the University of Hamburg. He was a visiting professor at the University of Cambridge from 1967 to 1968. He also taught at the Woods Hole Oceanographic Institution in Massachusetts from 1970 to 1972. In 1972, he became a Professor of Theoretical Geophysics at the University of Hamburg. He also became the Director of the Institute for Geophysics there.

From 1975 to 1999, Hasselmann was the first Director of the Max Planck Institute for Meteorology in Hamburg. From 1988 to 1999, he was also the Scientific Director at the German Climate Computing Centre (DKRZ). This center helps with climate calculations. He was also a leader in the European Climate Forum (now Global Climate Forum) for many years.

Understanding Climate Change

Hasselmann has written many important papers. These papers cover topics like how the climate changes, random processes, ocean waves, and how we can measure things from far away. His work on how ocean waves interact with each other made him famous in oceanography. He used special mathematical tools to describe these interactions.

He later became very interested in quantum field theory. He realized that scientists in other fields were using similar ideas. He said that it was "an eye-opener" to see how specialized scientists were. He felt it was important to learn from other areas of science.

In the field of climate change, Hasselmann made a big discovery. He found a way to mathematically describe how random weather patterns affect the climate. Imagine a heavy ball (the climate) being hit by many tiny, randomly moving particles (the weather). Even if nothing else changes, these random hits can make the ball move. This means the climate can change and vary even without big changes from outside. Knowing about short-term weather changes can help predict how the climate will vary.

Hasselmann also figured out how to find "fingerprints" of human-caused climate change. It's hard to see the clear signal of climate change when the climate naturally varies a lot. He developed a method to find this signal. This method helps scientists see how human activities are changing the climate.

Both his theory of random climate forces and his "fingerprint" method are very important for climate science.

Awards and Recognition

Klaus Hasselmann has received many awards for his work.

• In 1971, he received the Sverdrup Medal from the American Meteorological Society.
• In 1997, he was given the Symons Memorial Medal by the Royal Meteorological Society.
• In 2002, he received the Vilhelm Bjerknes Medal from the European Geophysical Society.
• In 2009, he won the BBVA Foundation Frontiers of Knowledge Award in Climate Change.
• In 2021, he was awarded the Nobel Prize in Physics. He shared it with Syukuro Manabe and Giorgio Parisi. They won for their important work on "physical modeling of Earth's climate, quantifying variability and reliably predicting global warming" and for "understanding of complex systems."

Hasselmann believes that solving climate change is possible. He has said that "the main obstacle is that the politicians and the public are not aware of the fact that problem is quite solvable. We have the technologies and there is a question of investing in these technologies. I think it is quite possible to respond to and solve the climate problem without a major impact in our way of life."

Mojib Latif, a well-known climate scientist, was one of his PhD students.

Publications

• M. Welp, K. Hasselmann, C. Jaeger, Climate Change and Paths to Sustainability: the Role of Science- Based Stakeholder Dialogues, The Environment