Paul Crutzen, Nobel laureate who studied ozone, dies
Paul Crutzen, a Nobel-winning chemist who revealed threats to the ozone layer, developed the concept of “nuclear winter” and concluded that humans were having such a profound impact on the planet that it was time to recognize a new geological epoch — the Anthropocene — died Jan. 28 at a hospital in Mainz, Germany. He was 87.
His death was announced by the Max Planck Institute for Chemistry in Mainz, where Crutzen directed the atmospheric chemistry department from 1980 until retiring in 2000. A spokeswoman for the institute, Susanne Benner, said he “suffered from several years of illness” but did not specify the cause.
Crutzen was raised in the Nazi-occupied Netherlands and initially worked as an engineer, not a scientist. Though he dreamed of an academic career, he enrolled at a technical school to spare his parents the cost of a university education, and built bridges in Amsterdam before starting a new life for himself in Sweden.
When he spotted a newspaper ad for a computer programming job at Stockholm College, he saw an opportunity. Despite lacking any experience, he applied for the position and got the job — and was soon sitting in on college classes, accumulating enough credits to get a master’s degree and apply for a doctorate program in meteorology.
Crutzen went on to spend decades investigating the interplay between humans and the atmosphere, studying the causes of air pollution, the impact of wildfires, the consequences of nuclear war and the depletion of the ozone layer, which earned him a share of the 1995 Nobel Prize in chemistry. For all his accomplishments, he was perhaps best known in recent years for popularizing “the Anthropocene,” a poetic new term that he first used in 2000.
“I was at a conference where someone said something about the Holocene, the long period of relatively stable climate since the end of the last ice age,” he told Fred Pearce, author of the climate-change book “With Speed and Violence” (2007). “I suddenly thought that this was wrong. The world has changed too much. So I said: ‘No, we are in the Anthropocene.’ I just made up the word on the spur of the moment. Everyone was shocked.”
He later learned that he was not the first to use the term “Anthropocene,” which biologist Eugene Stoermer had employed in the 1980s. Nor was he the first to offer a name for this human-dominated epoch of shrinking forests, rising temperatures and soaring population, which journalist Andrew Revkin once suggested calling the Anthrocene.
Ongoing debate
But Crutzen’s proposal, formalized in a 2002 Nature article titled “Geology of Mankind,” quickly took off, spurring an ongoing debate over whether it is time to rewrite geology textbooks and add a new epoch to the planet’s timetable, one that emphasizes the powerful role that humans play in shaping the Earth.
“Paul was very good at launching ideas that resonate with a lot of people, and that start to become a central theme of something,” said Guy Brasseur, a distinguished scholar at the National Center for Atmospheric Research in Boulder, Colo. In a phone interview, he called Crutzen a master of developing “simple ideas, simple models, that show the essence of a process.”
Crutzen was initially known for his work on the ozone layer, the thin atmospheric shield that protects plants and animals from ultraviolet radiation. In 1970, he demonstrated that compounds known as nitrogen oxides — spewed out by microbes in the soil — play a central role in controlling the level of ozone in the stratosphere.
His discovery marked a fundamental breakthrough in understanding the chemistry of the ozone layer, and shook up the debate over manufacturing supersonic transport planes such as the Concorde. Drawing on Crutzen’s research, some scientists feared that fleets of supersonic aircraft would pose a threat to the ozone layer by releasing nitrogen oxide into the atmosphere. The transport planes were never built in large numbers.
Paul Jozef Crutzen was born in Amsterdam on Dec. 3, 1933. His mother worked in a hospital kitchen, and his father waited tables but was often unemployed. The family later struggled to find food and fuel during the German occupation, amid a nationwide famine that became known as the “hunger winter.”
Long after he helped keep pollutants out of the atmosphere through his ozone research, Crutzen made a bold proposal to flood the air with sulfur in an effort to combat global warming. Such “geoengineering” efforts were worth further study, Crutzen argued, especially if humanity did not act quickly to stem emissions and alter consumption habits.