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Crutzen, Paul J.

Paul J. Crutzen

Paul J. Crutzen (born 1933) has led fellow scientists in the attempt to map out the chemicals that affect the ozone layer. He has been instrumental in learning how the ozone layer is formed and destroyed, and in uncovering the role industries play in its destruction. He was awarded the Nobel Prize in Chemistry in 1995 for discovering certain chemical compounds that reduce the ozone layer, and that certain bacteria in the soil can determine its thickness.

Crutzen was born on December 3, 1933, in Holland to Anna Gurk and Jozef Crutzen. He had one sister. Crutzen was raised in a rather cosmopolitan atmosphere filled with international ideas and attitudes. He grew up in a poor family in Nazi-occupied Holland. During his elementary school days World War II was going on, and he and his classmates had to move to a new building after their school was taken over by Nazi troops. Crutzen especially remembered the last winter of the war in 1944–45. He wrote in his autobiography on the Nobel Prize website, "During the cold 'hongerwinter' (winter of famine) of 1944–45, there was a severe lack of food and heating fuels. Also water for drinking, cooking and washing was available only in limited quantities for a few hours per day, causing poor hygienic conditions. Many died of hunger and disease, including several of my schoolmates."

Intention to Build Houses

Crutzen was one of the few children who was able to graduate from elementary school on time; the rest were kept back a year. At the time not all children were allowed to attend high school, but Crutzen was selected to do just that after he did very well on the entrance exam. He went to the Hogere Burgerschool, where he focused on natural sciences and learned to speak French, English, and German. He enjoyed playing soccer and bicycling and loved distance ice skating. He was also interested in chess, and at school he was interested in physics and math, not really liking chemistry at all. After graduation he went on to a two-year college, the Middelbare Technische School, because he could not afford to go to a university. He graduated with a degree in civil engineering in 1954. With this degree under his belt he set out to design bridges and houses.

Soon after graduation, while he was vacationing in Switzerland, Crutzen met Tertu Soininen. The couple married two years later and moved to Gavle, Sweden, in 1958, where Crutzen had obtained a job at a building construction bureau. The Crutzens had a daughter, Ilona, that December. Another girl, Sylvia, was born in March of 1964.

Switched to Atmospheric Chemistry

What Crutzen really wanted professionally, however, was to work for an academic department, not a building bureau, so when the opportunity presented itself he applied for a job as a computer programmer at the Institute of Meteorology at the University of Stockholm. He had no experience in computers, but at the time there were few who did, and he was accepted from a large candidate pool to take on the position. The family moved to Stockholm. He was originally interested in mathematics, but soon lost his passion for it in favor of atmospheric chemistry. While working, Crutzen also earned a doctorate in meteorology at the university.

In 1965 Crutzen went to help a U.S. scientist develop a model of the stratosphere. It was this project that awakened Crutzen's interest in the chemical makeup of the ozone layer. He started reading everything he could on the subject, his interest growing with each new piece of information. It also gave him an idea of the state of research on the ozone layer at that time. He went back to Sweden with a new purpose for his degree research. Crutzen stated in his autobiography on the Nobel Prize website, "Instead of the initially proposed research project, I preferred research on stratospheric chemistry, which was generously accepted."

Researched Ozone Layer

At the time the current research areas at the University of Stockholm were dynamics, the physics of clouds, the carbon cycle, studies of the chemical composition of rainwater, and especially acid rain, which was one of the hottest research topics at that time. However, Crutzen maintained an interest in studying the ozone layer.

Ozone itself is a bluish gas that has a strong scent and is irritating to living organisms. It has three oxygen atoms and forms naturally in the atmosphere through a process called photochemical reaction, having to do with the chemical reaction of light. The ozone layer is located ten miles above the surface of the Earth and is approximately 20 to 30 miles thick. Its purpose is to absorb the ultraviolet radiation that the sun emits. Atmospheric warming occurs when that layer begins to deplete.

In 1970 Crutzen discovered that certain bacteria in the soil gave off a nitrous oxide gas which rose all the way to the stratosphere, where it was changed by a photochemical process into two chemicals, nitric oxide and nitrogen dioxide. He learned that these two gases were part of what caused the ozone to shrink in size. This one realization led scientists across the globe to examine chemicals found on earth to see how they affected the ozone layer's size.

Studied Effects of Smoke and Nuclear War

Crutzen went on from this research to become in 1977 the director of the National Center for Atmospheric Research (NCAR) in Boulder, Colorado. From there he worked on how burning trees and brush in Brazil effected the atmosphere. In Brazil farmers would clear the forests every year by burning them down. It was thought that this burning was releasing carbon monoxide and other carbon compounds into the air that were causing the greenhouse effect, the warming of the atmosphere. When Crutzen collected samples and did his research, however, he found out that the exact opposite was happening. The yearly smoke was actually decreasing the amount of carbon dioxide in the atmosphere. This discovery intrigued Crutzen, and he went on to study the effects of other kinds of smoke on the atmosphere, especially the smoke that would come from a global disaster such as a nuclear war.

Once he made his interest in researching such a topic known, several sponsors came forward. The journal Ambio paid Crutzen and his University of Colorado colleague John Birks to study how a nuclear war would effect the planet. The pair put together a model of a worldwide nuclear war. According to the scientists nuclear war would have a fallout of black carbon soot that would result from fires raging across the planet. This soot would absorb up to 99 percent of the sunlight that the Earth needs to survive. This would cause the entire planet to be thrown into a state of perpetual winter so vast that it would destroy every living thing. For proposing this theory Crutzen was named "Scientist of the Year" by Discover magazine in 1984 and was awarded the esteemed Tyler Award in 1988.

When these theories and others about the destructive nature of certain chemicals on the ozone layer came to the attention of the general public and to governments around the world, an international treaty was drawn up in 1987. Called the Montreal Protocol, it was negotiated by the United Nations and was eventually signed by 70 countries. The protocol stated that these countries would phase out, no matter how slowly, the production of chlorofluorocarbons and other ozone-depleting chemicals by the year 2000. The United States managed to stop producing things with the harmful chemicals in them by the year 1995, although it still remained the leading producer of carbon emissions in the world. The hole in the ozone layer over the South Pole was still increasing in 2000, but it was thought that it was because of existing products with the harmful chemicals in them that would take a while to deplete. A full reversal of the problem was not expected to take place for hundreds of years.

Crutzen stayed at the NCAR until 1980. At the same time he taught classes at Colorado State University in the department of Atmospheric Sciences. He became director of the Atmospheric Chemistry Department at Germany's Max Planck Institute for Chemistry in 1980 and remained as such until 2000. From 1992 on he taught part-time at Scripps Institution of Oceanography at the University of California and also at Utrecht University's Institute for Marine and Atmospheric Sciences in the Netherlands.

Suggested Interim Solution to Ozone Problems

In 2006 Crutzen was acknowledged to have come up with a solution for helping to stave off the effects of global warming. He suggested that the chemical composition of the Earth's upper atmosphere be altered. Attempts to stave off man-made alterations to the atmosphere had been so meager that according to Crutzen a more drastic approach was necessary. His suggestion was to release some sulphur into the upper atmosphere. The sulphur should reflect sunlight and the heat from it back into space. It was a very controversial solution, but has been receiving some serious consideration because of Crutzen's known track record of excellence in the past. The sulphur could either be scattered by balloons designed for high altitude flight or could be shot into the air by heavy artillery shells. According to the London Independent, "Such 'geo-engineering' of the climate has been suggested before, but Professor Crutzen goes much further by drawing up a detailed model of how it can be done, the timescales involved, and the costs."

The idea has raised objections around the globe, most often because such an operation, scientists fear, would be seen as a quick fix and then governments would cease to search for more permanent solutions to the problem. Crutzen has argued that this would be a stopgap measure and that pressures on governments to improve their emissions would remain. In his opinion this would be a way to temporarily reduce global warming issues while countries worked more fervently to change their practices.

His plan was modeled in part on the eruption of the Mount Pinatubo volcano in 1991. Thousands of tons of sulphur were thrown into the air when the volcano erupted causing temperatures around the globe to decrease. Putting the sulphur into the stratosphere rather than lower down, as in the case of the volcano, would create a year or two of lower temperatures rather than just a few weeks. The project would cost about $25 to $50 billion, but it is Crutzen's belief that that cost is nothing to what global warming is doing to all life on Earth. Because of his contributions to modern science, Crutzen was elected in 2006 to become a foreign member of the Royal Society, the United Kingdom's national academy of science and the world's oldest scientific academy in uninterrupted existence. As of 2007 he continued his studies into improving the atmosphere.


Notable Scientists: From 1900 to the Present, Gale Group, 2001.

World of Chemistry, 2 volumes, Gale Group, 1999.

World of Earth Science, Gale, 2003.

World of Scientific Discovery, 2nd edition, Gale Group, 1999.


Environment, April 2004; October 2005.

Independent (London, England), July 31, 2006.

Times (London, England), October 12, 1995.

Times of India, August 1, 2006.


"Paul J. Crutzen, Noble Prize Website, (January 2, 2007).

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Crutzen, Paul J. (1933- )

Crutzen, Paul J. (1933- )

Dutch meteorologist

Paul Crutzen is one of the world's leading researchers in mapping the chemical mechanisms that affect the ozone layer. He has pioneered research on the formation and depletion of the ozone layer and the potential threats placed upon it by industrial society. Crutzen has discovered, for example, that nitrogen oxides accelerate the rate of ozone depletion. He has also found that chemicals released by bacteria in the soil affect the thickness of the ozone layer. For these discoveries, he has received the 1995 Nobel Prize in Chemistry, along with Mario Molina and Sherwood Rowland for their separate discoveries related to ozone and how chlorofluorocarbons (CFCs) deplete the ozone layer. According to Royal Swedish Academy of Science, "by explaining the chemical mechanisms that affect the thickness of the ozone layer, the three researchers have contributed to our salvation from a global environmental problem that could have catastrophic consequences."

Paul Josef Crutzen was born December 3, 1933, to Josef C. Crutzen and Anna Gurek in Amsterdam. Despite growing up in a poor family in Nazi-occupied Holland during 19401945, he was nominated to attend high school at a time when not all children were accepted into high school. He liked to play soccer in the warm months and ice skate 5060 miles (8097 km) a day in the winter. Because he was unable to afford an education at a university, he attended a two-year college in Amsterdam. After graduating with a civil engineering degree in 1954, he designed bridges and homes.

Crutzen met his wife, Tertu Soininen, while on vacation in Switzerland in 1954. They later moved to Sweden where he worked as a computer programmer for the Institute of Meteorology and the University of Stockholm. He started to focus on atmospheric chemistry rather than mathematics because he had lost interest in math and did not want to spend long hours in a lab, especially after the birth of his two daughters. Despite his busy schedule, Crutzen obtained his doctoral degree in Meteorology at Stockholm University at the age of 35.

Crutzen's main research focused on ozone, a bluish, irritating gas with a strong odor. Ozone is a molecule made up of three oxygen atoms (O3) and is formed naturally in the atmosphere by a photochemical reaction. The ozone layer begins approximately 10 miles (16 km) above Earth's surface, reaching 2030 miles (3248 km) in height, and acts as a protective layer that absorbs high-energy ultraviolet radiation given off by the sun .

In 1970, Crutzen found that soil microbes were excreting nitrous oxide gas, which rises to the stratosphere and is converted by sunlight to nitric oxide and nitrogen dioxide. He determined that these two gases were part of what caused the depletion of the ozone. This discovery revolutionized the study of ozone and encouraged a surge of research on global biogeochemical cycles .

In 1977, while he was the director of the National Center for Atmospheric Research (NCAR) in Boulder, Colorado, Crutzen studied the effects of the mass burning of trees and brush in the fields of Brazil. The theory at the time was that this burning caused more carbon compoundstrace gases and carbon monoxideto enter the atmosphere. These gases were assumed to cause the greenhouse effect , or a warming of the atmosphere. Crutzen collected and examined this smoke in Brazil and discovered that the complete opposite was occurring. He stated in Discover magazine, "Before the industry got started, the tropical burning was actually decreasing the amount of carbon dioxide in the atmosphere." The study of smoke in Brazil led Crutzen to further examine what effects larger amounts of different kinds of smoke might have on the environment, such as smoke from a nuclear war.

The journal Ambio commissioned Crutzen and John Birks, his colleague from the University of Colorado, to investigate what effects nuclear war might have on the planet. Crutzen and Birks studied a simulated worldwide nuclear war. They theorized that the black carbon soot from the raging fires would absorb as much as 99% of the sunlight. This lack of sunlight, coined "nuclear winter," would be devastating to all forms of life. For this theory Crutzen was named "Scientist of the Year" by Discover magazine in 1984, and awarded the prestigious Tyler Award four years later.

Because of the discoveries by Crutzen and other environmental scientists, a crucial international treaty was established in 1987. The Montreal Protocol was negotiated under the auspices of the United Nations and signed by 70 countries to slowly phase out the production of chlorofluorocarbons and other ozone-damaging chemicals by the year 2000. However, the United States had ended the production of CFCs five years earlier, in 1995. According to the New York Times, "the National Oceanic and Atmospheric Administration reported in 1994, while ozone over the South Pole is still decreasing, the depletion appears to be leveling off." Even though the ban has been established, existing CFCs will continue to reach the ozone, so the depletion will continue for some years. The full recovery of the ozone is not expected for at least 100 years.

From 1977 to 1980, Crutzen was director of the Air Quality Division, National Center for Atmospheric Research (NCAR), located in Boulder, Colorado. While at NCAR, he taught classes at Colorado State University in the department of Atmospheric Sciences. Since 1980, he has been a member of the Max Planck Society for the Advancement of Science, and he is the director of the Atmospheric Chemistry division at Max Planck Institute for Chemistry. In addition to Crutzen's position at the institute, he is a part-time professor at Scripps Institution of Oceanography at the University of California. In 1995, he was the recipient of the United Nations Environmental Ozone Award for outstanding contribution to the protection of the ozone layer. Crutzen has co-authored and edited several books, as well as having published several hundred articles in specialized publications.

See also Global warming; Greenhouse gases and greenhouse effect; Ozone layer and hole dynamics; Ozone layer depletion

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"Crutzen, Paul J. (1933- )." World of Earth Science. . 22 Aug. 2017 <>.

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"Crutzen, Paul J. (1933- )." World of Earth Science. . Retrieved August 22, 2017 from