Three environmental scientists who "have contributed to our salvation from a global environmental problem that could have catastrophic consequences" were awarded the Nobel Prize in chemistry Wednesday for showing that human activities such as spray cans and air conditioners can imperil the fragile ozone layer that protects the world from the dangerous ultraviolet radiation of the sun.
The Royal Swedish Academy of Sciences awarded the prize to Professor Mario Molina, 52, of the Massachusetts Institute of Technology in Cambridge, Mass.; Professor F. Sherwood Rowland, 68, of the University of California at Irvine, Cal., and Professor Paul Crutzen, 62, a Dutch citizen who is a scientist at the Max Planck Institute for Chemistry in Mainz, Germany. They will share the prize money of $1 million.
It is the first time the Nobel Prize has recognized research into man-made impacts on the environment. The discoveries led to an international environmental treaty which by the end of this year bans the production of industrial chemicals that reduce the ozone layer.
In its announcement, the Swedish Academy wrote that "if all the ozone in the atmosphere were compressed to a pressure corresponding to that at the earth's surface, the layer would be only 3 mm [1/8 inch] thick....The thin ozone layer has proved to be an Achilles heel that may be seriously injured by apparently moderate changes in the composition of the atmosphere."
Ozone--a gas with molecules consisting of three oxygen atoms--is highly dispersed. The highest contents of ozone exist in the ozone layer that is 15 to 50 km (9 to 31 miles) above the earth. Without the protective layer of ozone, animals and plants could not exist on land. Significant depletion of ozone can cause increased skin cancer, cataracts and immune system damage for humans, and mutations in many species.
In 1970, Crutzen showed that nitrogen oxides accelerate the rate of reduction of ozone. The Academy noted that another threat to the ozone layer came from the supersonic aircraft planned in the 1970s, which would be capable of releasing nitrogen oxides right in the middle of the ozone layer at altitudes of 20 km (12 miles).
In 1974, Molina was a postdoctoral fellow in Professor Rowland's laboratory at the University of California at Irvine. Molina was the lead author on their paper, in the British magazine Nature, of their research on the threat to the ozone layer from chlorofluorocarbon (CFC) gases or freons, which were being used as propellants in spray cans, as the cooling medium in refrigerators and air conditioners, and in plastic foams. Their prediction of significant depletion of the ozone layer over a period of decades "created an enormous attention," the Academy said.
"Many were critical of Molina's and Rowland's calculations, but yet more were seriously concerned by the possibility of a depleted ozone layer. Today we know that they were right in all essentials. It was to turn out that they had even underestimated the risk," the Academy said.
Their research predicting an ozone "hole" laid the groundwork for its discovery in 1985 over the South Pole by British scientist Joseph Farman and colleagues. Ozone depletion around most of the globe "is caused chiefly by ozone reacting chemically with chlorine and bromine from industrially manufactured gases," the Academy said.
The scientific research by Crutzen, Molina, Rowland and others led to the 1987 United Nations' Montreal Protocol, which will ban the most dangerous gases from 1996 on. "Given compliance with the prohibitions, the ozone layer should gradually begin to heal after the turn of the century. Yet it will take at least 100 years before it has fully recovered," the Academy said.
At a news conference at MIT, Professor Molina commented, "It's very rewarding to work with problems that affect society in a very direct way.
"Another very rewarding aspect of the research... is that we have seen how society responds to it," Professor Molina said. "We not only made some doomsday scenarios that something bad might happen eventually, but we as a community were actually able to convince society to do something about it."
"So the problem of CFCs is, to a very significant extent, solved. Society decided to ban the compounds, and it has done this in a clever way without doing away with all the benefits. People have to benefit from air conditioning in cars, from spray cans, and from refrigeration, and you can still use plastic foam. It's just not essential to use this type of harmful compounds to get these benefits," said Molina, a professor in both the MIT Department of Earth, Atmospheric and Planetary Sciences and the Department of Chemistry.
Molina endured strong criticism from industry when the research was published 21 years ago. He noted that at the time, environmental research "was not well accepted in the scientific community. Maybe it was thought that the issues were too complicated to understand well. But I think that over the years the scientific community ... has shown that one can do rigorous science, with scientific hypotheses that can be tested, and thankfully this leads to the acceptance of these types of ideas by the scientific community in general."
"It does feel like a vindication" of his work, he said. The work is still criticized by some--two U.S. Congressmen last month introduced legislation seeking to postpone the implementation of the ban on ozone-depleting chemicals.
Dr. Molina commented: "In terms of the skeptics, there's only a very small group of scientists that disagree with what I believe is a pretty amazing international consensus. The science is really very clear, if you look at all the evidence. There is very little doubt that it is the CFCs that [are causing] ozone depletion in Antarctica. So it has to do mostly with people who haven't really looked carefully at the evidence.
Professor Robert J. Birgeneau, MIT dean of science, introduced Molina as "a wonderful person --a warm, gentle, dignified kind of man who is extremely responsible and a natural leader in a very quiet way." MIT President Charles M. Vest commented, "We are extremely pleased that such a productive and respected member of the MIT community has won the Nobel Prize in chemistry. This award emphasizes that the most fundamental scientific inquiry can turn out to have extremely important ramifications for our world. It also shows that sometimes nice guys finish first."
Professor Thomas Jordan, head of MIT's Department of Earth, Atmospheric and Planetary Sciences, told the news conference, "It's important to realize that Mario's work didn't stop with his landmark hypothesis. With the discovery of the Antarctic ozone hole, he began a second phase of major contributions in this area. He sought to understand why it was that the ozone was depleted specifically in the Antarctic, in some of the coldest parts of the stratosphere. And this new phase of his work led to the discovery that the relatively benign chlorine compounds can decompose in the ice clouds that occur in the cold Antarctic stratosphere, leading to the release of chemicals that are destructive to ozone.
"This was a truly beautiful piece of fundamental chemistry, and added significantly to his scientific achievements. He proposed and demonstrated in the laboratory the nature of this fundamental catalytic reaction, which we now believe is largely responsible for the depletion of ozone associated with the Antarctic ozone hole," Jordan said. Jordan paid tribute to Molina's contributions to public service and to teaching. "It was through his scientific work and his work to notify the public and the people who set the national policy and international policy that has led to the Montreal Protocol, signed in 1987, which is leading to the phase-out of CFCs... He is an outstanding educator both in the classroom and as a supervisor of graduate students." Molina is a member of the President's Council of Advisors on Science and Technology (PCAST), an advisory group to the president of the United States. Born in Mexico and now a naturalized American citizen, Molina is the first native scientist of Mexico and is believed to be the first Mexican-American to win a Nobel Prize. (Mexican citizens won the Nobel Prize for literature in 1990 and the Nobel Prize for peace in 1982.)
The award brought to 28 the number of Nobel Prizes won by MIT faculty, alumni and staff in the past 40 years. Current and emeritus members of the faculty have won the prize in medicine/physiology (4), physics (4), economics (3) and chemistry (1). In addition, a staff doctor at MIT was a founder of the International Physicians for the Prevention of Nuclear War, which won the Nobel Peace Prize in 1985.
Molina was born in Mexico City in 1943 and came to MIT in 1989 after holding teaching and research positions at the Universidad Nacional Autonoma de Mexico; the University of California, Berkeley; the University of California, Irvine and the Jet Propulsion Laboratory at the California Institute of Technology. He is the Lee and Geraldine Martin Professor of Environmental Sciences at MIT.
In addition to the 1974 publication, Dr. Molina was also principal author or co-author on a series of papers from 1976-86 that defined and refined the relevant kinetics of the compounds that act as "temporary reservoirs" for the free radicals responsible for catalytic ozone destruction. Dr. Molina's latest research directions include work at the interface of the atmosphere-biosphere, which is critical to understanding global climate-change processes. Sponsors of his research have included the National Science Foundation, NASA, the Environmental Protection Agency, Federal Aviation Administration and a number of industrial sponsors.
Professor Molina has received several awards for his scientific work including the Tyler Award in 1983, the Esselen Award of the American Chemical Society in 1987, and the Newcomb-Cleveland Prize of the American Association for the Advancement of Science, for his 1987 paper in Science describing his work on the Antarctic Ozone Hole chemistry. In 1989 he received the NASA Medal for Exceptional Scientific Achievement, and from 1990-92 he was a Pew Scholar on Conservation and the Environment.
In 1994, Professor Molina was named by President Bill Clinton to serve on the 18-member President's Committee of Advisors on Science and Technology (PCAST). The PCAST advises the President on issues involving science and technology in achieving national goals, and assists the cabinet-level National Science and Technology Council in securing private-sector participation in its activities.
Molina holds the chemical engineer degree (1965) from the Universidad Nacional Autonoma de Mexico, a postgraduate degree (1967) from the University of Freiburg, West Germany, and the PhD (1972) from the University of California, Berkeley.
Professor Molina is married to Dr. Luisa T. Molina, his co-author on many papers, who also conducts research at MIT related to ozone depletion. She is a Research Scientist in the Department of Earth, Atmospheric and Planetary Sciences. Their son, Felipe, is a freshman at Brown University. The family lives in Lexington, Mass.