Biography: Mario Molina
Nobel Prize in Chemistry

José Mario Molina-Pasqual Henriquez was born and raised in Mexico City. From an early age, Mario was fascinated by the natural sciences. When he encountered his first microscope, he was thrilled to observe the organisms living in a drop of ordinary pond water. His father was a prominent attorney; when Mario was grown, the elder Molina would serve his country as Ambassador to Ethiopia, Australia and the Philippines.

Many of the Molinas were educated professionals, but the only scientist in the family was Mario's aunt, Esther Molina, a chemist who encouraged his love of the sciences. Young Mario acquired chemistry sets and built his own laboratory in an unused bathroom of the family home. The other major interest of his childhood was music. He played the violin and considered the possibility of a career in music, but found himself increasing drawn to chemistry, and enjoyed reading biographies of the great chemists. At age 11, he was sent briefly a boarding school in Switzerland to begin the study of German, a language his parents hoped would be useful to a budding chemist.

He returned to Mexico City to complete his secondary education and went on to the Autonomous National University of Mexico (UNAM), where he studied chemical engineering, a course that provided more training in mathematics than was available in the pure chemistry curriculum. After receiving his chemical engineering degree, Molina enrolled in graduate courses at the University of Freiburg, Germany, where she spent two years carrying out research in the kinetics of polymerization. He had arrived in Freiburg feeling somewhat underprepared in math and physics, and after completing his work at Freiburg, he traveled to Paris for a few months of intensive mathematical study. Molina hoped to pursue doctoral studies in the United States, but returned to Mexico first, to teach at UNAM, where he established the first graduate program in chemical engineering.

In 1968, Molina enrolled in the Ph.D. program in physical chemistry at the University of California, Berkeley. There he expanded his knowledge of physics and mathematics as well as physical chemistry, and joined a research group led by Professor George Pimentel; he would later credit Pimentel as a great influence on his development as a scientist. Under Pimentel's direction, Molina conducted important research employing chemical lasers. He was among the first to determine that irregularities in laser behavior that had been dismissed as noise were in fact "relaxation oscillations" that could be readily understood through the fundamental equations of laser emission. The Berkeley campus of the late '60s and early '70s was still reeling from the tumultuous political events of the preceding years, and for the first time, Mario Molina began to consider the social implications of scientific research, specifically the possible destructive application of laser technology in warfare.

Molina completed his doctorate in 1972, and remained in Berkeley for another year, continuing his research in chemical dynamics, before joining the research group led by Professor Sherwood "Sherry" Rowland at the University of California, Irvine. Rowland offered his young postdoctoral fellow a choice of research options and Molina's eye fell on the question of chlorofluorocarbons, industrial chemicals, apparently harmless to man, which were known to accumulate in the atmosphere.

Chlorofluorocarbons (CFCs), of which the most common form were the hydrochlorofluorocarbons, produced by the DuPont company under the brand name "Freon," were widely used in refrigeration, as a propellant in aerosol spray cans and in the manufacture of plastic foam. Molina and Rowland were very familiar with the chemical properties of these compounds, but not with their behavior in the atmosphere. What became of CFCs after they were released was an intrinsically interesting problem, although Molina had no reason to believe that the circulation of these gases in the atmosphere posed any particular danger to living things, since they are not toxic in themselves.

Molina learned that these compounds ascend intact into the stratosphere. There, it was expected that solar radiation that would destroy them. What Molina found was that CFCs exposed to solar radiation in the stratosphere break down into their component elements, producing a high concentration of pure chlorine atoms. Chlorine, he knew, destroys ozone. A layer of ozone in the stratosphere -- between nine and 31 miles above the Earth -- is what protects living things from the ultraviolet rays of the sun. If sufficient CFCs were released into the atmosphere, the ozone layer would be so depleted that the unfiltered ultraviolet rays reaching the Earth's surface would cause increased rates of skin cancer, cataracts and immune disorders among humans, as well as damage to agricultural crops and to the marine phytoplankton essential to the ecological balance of the world's oceans. A pure research problem had presented a serious social question. Molina shared his findings with Professor Rowland, as well as other chemists and atmospheric scientists. Everywhere, they found confirmation of their worst suspicions: the volume of CFCs being released into the atmosphere was indeed great enough to damage the ozone layer. What Molina lacked was evidence that such damage had already taken place.

Molina and Rowland published their findings in a 1974 issue of the journal Nature. The alarming conclusion of their study attracted considerable attention, but when they called for a halt to the production of CFCs, they were met with intense criticism and even ridicule from industry interests and from more cautious members of the scientific community. One industrialist was reported as calling their theory "a science fiction tale...a load of rubbish...utter nonsense." Another wrote to the University of California to complain. Molina took his case to a larger public, and testified before a committee of the U.S. Congress. Despite resistance from industry, the U.S. National Academy of Sciences (NAS) released a report in 1976 that confirmed the essential premises of Molina's ozone depletion hypothesis, and more resources were assigned to study the problem.

Meanwhile, Molina accepted a faculty appointment at Irvine, where he established an independent program to study the atmospheric impact of other industrial chemicals. The academic duties of this professorship took more time from his laboratory research than he cared for, and in 1982 he transferred to the Jet Propulsion Laboratory at California Institute of Technology (Caltech) in Pasadena, where he could continue hands-on research.

In 1985, scientists of the British Antarctic Survey detected a large and growing gap in the ozone layer over the Earth's Southern Hemisphere. Although the "ozone hole" was centered over Antarctica, its growth appeared to correspond with a dramatic increase in skin cancer rates in Australia and other countries of the Southern Hemisphere. Molina and his group were able to demonstrate that the ice crystals in the polar stratosphere had amplified the ozone-destructive capacity of CFCs. They also determined that chlorine peroxide, a previously unstudied compound, was contributing significantly to the depletion of the ozone layer over the Antarctic.

The announcement vindicated Molina's hypothesis and galvanized public opinion. By the end of 1985, 20 nations, including most of the major CFC producers, signed the Vienna Convention, which established a framework for negotiating international regulation of ozone-depleting substances. The Vienna Convention was soon amended by the Montreal Protocol, pledging the signatories to end CFC emissions. Industry groups continued to protest that the evidence was unclear. In 1987, representatives of DuPont testified before the U.S. Congress that "there is no immediate crisis that demands unilateral regulation." Despite this resistance, world leaders, including environmental skeptics such as President Ronald Reagan of the U.S. and Prime Minister Margaret Thatcher of the U.K., signed the protocol in 1987, and more nations quickly followed. Nearly 200 states, including every member of the United Nations, have now ratified the protocol. Production of CFCs has all but stopped. Economically viable alternatives to the offending chemicals have been found, further damage to atmospheric ozone has halted and it is expected that by the midway point of the current century the ozone layer will have recovered completely.

In 1989, Mario Molina returned to academic life at the Massachusetts Institute of Technology, where he continued his research on global atmospheric issues. Dr. Molina received the 1995 Nobel Prize in Chemistry for "contributing to our salvation from a potential global environmental catastrophe." Asteroid 9680 Molina was later named in his honor. In 2005, Molina moved from MIT to join the University of California at San Diego and the Center of Atmospheric Sciences at Scripps Institution of Oceanography. He now divides his time between San Diego and his native Mexico City, where he has created a center for strategic studies in energy and the environment. Much of his current work is related to issues of air quality and development. His center in Mexico is working to improve the notoriously poor air quality of the capital, while his laboratory in San Diego investigates the chemical properties of atmospheric particles.

Dr. Molina is married to Guadalupe Alvarez; his son by a previous marriage is a practicing physician in Boston, Massachusetts. In addition to his academic and research responsibilities, Dr. Molina has served on the boards of numerous foundations and on the President's Committee of Advisors in Science and Technology. More recently, he served as an environmental advisor on the transition team of President Barack Obama.