The food chain in the oceans would be starting to collapse and food crops would be beginning to burn from extreme ultraviolet radiation damage but for the brilliant mind and dogged determination of a young Mexican immigrant.
Mario Molina was born into a leading family in Mexico City, the son of an attorney who went on to be Mexico’s ambassador to to Ethiopia, Australia and the Philippines. The only scientist in the family, his aunt Esther Molina, a professional chemist, encouraged his interest in chemistry and science when he was a young boy. www.achievement.org/...
Mario kept the passion for chemistry he discovered as a young boy and earned a chemical engineering degree from the Autonomous National University of Mexico (UNAM), but Mexico lacked the resources needed for his graduate education. He first studied in Germany, then returned to UNAM with his masters degree to set up Mexico’s first graduate program in chemical engineering.
The University of California, Berkeley had a reputation for student activism in the late 1960s and early 1970s but more importantly it was a hotbed for world-changing science. Berkeley had attracted a diverse collection of scientists from across the globe to build a great research university. Molina earned his PhD in 1972 at Berkeley studying chemical dynamics using lasers. Then, like many young Mexicans in the 1970s, he moved to southern California for a job.
It wasn’t just any job. Professor Sherwood (Sherry) Rowland had been lured from Chicago to the just built University of California campus in the center of the yet to be developed Irvine ranch. Sherry Rowland, who earned his PhD at the University of Chicago studying under Nobel Prize winner, Carbon-14 dating inventor, Willard F. Libby, was hired to build a world class chemistry research program at the Irvine campus. Rowland was an imposing 6’ 5” tall, an outstanding baseball player in his youth, known for his meticulous scientific research, who did not suffer fools lightly. He selected Molina for the post-doc job based on merit.
Rowland offered Molina a choice of topics for post doctoral study. Molina chose, in part because the interest he had developed in social concerns at Berkeley, to investigate the fate of the virtually indestructible compounds known by the trade name of Freon, that were starting to build up in the atmosphere. Rowland’s PhD adviser Bill Libby had investigated fluorine chemistry during WWII for the Manhattan Project. Much of Libby’s war work was classified (I know this from personal communication because I worked with Bill Libby in the 1970s) but classes of practical compounds, from Teflon to Freon were developed built on the chemistry discoveries made during the war years. Rowland must have suspected that the build up of man made gases in the atmosphere could have serious unintended consequences but he did not know what those consequences might be. It would take his young post-doc, Mario Molina to discover the impacts of the class of chemicals that were first studied by Bill Libby to develop the gaseous diffusion process of uranium enrichment.
In 1973 Molina, a postdoctoral researcher working in the laboratory of F. Sherwood Rowland at the University of California, Irvine, made an unsettling discovery. He had been investigating a class of compounds called chlorofluorocarbons, or CFCs. CFCs were used as refrigerants, aerosol sprays, and in making plastic foams. Molina wondered what happened to them once they were released into the atmosphere.
www.sciencehistory.org/...
How CFCs Destroy Ozone
Molina’s study was a hypothetical one based on computer modeling, but his results suggested that CFCs could, in theory, destroy an oxygen compound called ozone under the conditions that exist in the upper atmosphere. Far above the earth’s surface, in the stratosphere, a thin layer of ozone floats, protecting us from the sun’s ultraviolet radiation. Molina, just a young scientist at the time he did the study, was nervous about talking to Rowland about his theory of how CFCs might destroy ozone. But if CFCs really could reduce ozone at a predicted rate of 7 percent after 60 years, the world would be in trouble.
According to Molina’s theory, the same photons from ultraviolet light that break oxygen molecules apart to produce oxygen atoms can also break CFCs apart to release chlorine atoms, among other products. Since the chlorine atom has an unpaired electron, it is a radical. Radicals are very reactive; so chlorine atoms react easily with molecules of ozone. When a chlorine atom encounters an ozone molecule (O3), it takes one of the oxygen atoms away, leaving O2 and chlorine oxide (ClO). ClO is also a reactive radical and reacts quickly with another ozone molecule, converting it to two O2 molecules, and freeing the Cl to do still more damage. Since the radical Cl atom starts this whole reaction but is not consumed in the process, it is a catalyst for the ozone destruction reaction.
Chlorofluorocarbons (CFCs) were a triumph of the chemical industry and a mere curiosity in atmospheric science when Sherwood (Sherry) Rowland, with his postdoc Mario Molina, recognized in 1973 that these seemingly inert gases posed a threat to Earth's ozone layer. www.nature.com/...
Returning home one evening, Rowland remarked to his wife Joan that the research “is going very well, but it may mean the end of the world”.
In their laboratory at the University of California, Irvine, Molina and Rowland had discovered that CFC-11 (CFCl3) and CFC-12 (CF2Cl2), then widely used as refrigerants and aerosol propellants, readily absorbed ultraviolet light and broke down to release reactive chlorine. This work was the first step in tracing the causal chain linking industrial production of CFCs with global ozone depletion — and won Rowland and Molina the 1995 Nobel Prize in Chemistry, shared with Dutch chemist Paul Crutzen.
The seminal paper published in 1974 in Nature is accessible at this link. courses.seas.harvard.edu/…
Sherry Rowland passed away in 2012 after saving the world and building UCI’s chemistry department into a world-class institution. He was a force on campus into his early 80s. news.uci.edu/…
Rowland and Molina faced death threats for their environmental advocacy, but they persisted.
Nearly 40 years ago, Rowland and postdoctoral student Mario Molina made a shocking discovery: A single chlorine atom byproduct from aerosol hair sprays, deodorants and other popular consumer products could chew up 100,000 ozone atoms in the stratosphere. The stratospheric ozone layer, 12 to 30 miles above Earth, protects life on the planet from harsh solar radiation.
“Mario and I realized this was not just a scientific question, but a potentially grave environmental problem involving substantial depletion of the stratospheric ozone layer,” Rowland said later. “Entire biological systems, including humans, would be at danger from ultraviolet rays.”
They decided they had to advocate for a ban on consumer products that were earning billions annually. Industry representatives fought back: At one point, Aerosol Age, a trade journal, speculated that Rowland was a member of the Soviet Union’s KGB, out to destroy capitalism. Even some fellow scientists grumbled that he was going overboard with a hypothesis.
Rowland calmly stayed the course, working to convince everyone from Margaret Thatcher to Al Gore to reporters from hundreds of news outlets of what was at stake. Scientists doing similar research stuck by him, and consumers stopped using the sprays. One who believed him from Day One was his wife, Joan. When he told her the results of their calculations in 1974, she searched the house and threw out every spray can.
It took far longer for others to act – 13 years and the discovery by British scientists of a gaping hole in the ozone layer over the Antarctic – before an international treaty was signed prohibiting sale of the harmful chemicals. Today, 196 nations have signed the Montreal Protocol, widely viewed as the single most successful international environment agreement to date. Production and use of ozone-depleting substances has been reduced more than 95 percent.
The chemical industry led an intensive campaign to try to discredit Molina and Rowland’s research, but their work was validated internationally. www.wunderground.com/… There were a few congressmen who acted as shills for industry, but the Republican party did not oppose the treaty. The Republican party had not yet been captured by industry.
Mario Molina and Sherry Rowland persisted and, with the help of NASA and the global scientific community, succeed in getting the Montreal protocol passed and signed by Ronald Reagan. If they had failed, the marine food chain may have started collapsing this decade because marine plankton are very sensitive to UV and they already at their UV viability limits. The demise of marine plankton would eliminate one of the earth’s primary sources of oxygen. Early life forms thrived in a low oxygen high UV environment, but most advanced life forms would not survive.
UV-B and Marine Organisms
Plankton form the foundation of aquatic food webs. Plankton productivity is limited to the euphotic zone, the upper layer of the water column in which there is sufficient sunlight to support the photosynthesis of food. Since UV radiation has the ability to penetrate up to 20 metres down in clear water, plankton and other light dependent organisms often experience cell damage, much as human DNA can be damaged by the strong solar radiation. Both plant (phytoplankton) and animal (zooplankton) species are damaged by UV-radiation even at current levels. As with certain land plants, some species are more sensitive to UV-light at critical stages in their life cycle, and changes in radiation may shorten the breeding period to intolerable levels. As plankton make up the base of the marine food chain, changes in their number and species composition will influence fish and shellfish production world-wide. These kinds of losses will have a direct impact on the food supply.
Solar UV-B radiation has also been found to cause damage to the early developmental stages of fish, shrimp, crab, amphibians and other animals. The most severe effects are decreased reproductive capacity and impaired larval development. Even at current levels, solar UV-B radiation is a limiting factor, and small increases in UV-B exposure could result in a significant reduction in the size of the population of animals that eat these smaller creatures.
Ozone Depletion and Marine Organisms
Research indicates that many plankton species already seem to be at or near their maximum tolerance of UV radiation. Thus, even small increases in UV-B levels may have a dramatic impact on plankton life and on entire marine ecosystems. Some research suggests that ozone depletion is more likely to change the composition of living organisms on the ocean's surface than to reduce its overall mass.
If ozone-layer depletion reached 15% over temperate waters, it would take less than five days in summer for half the zooplankton in the top metre of these waters to die from the increased radiation. Additionally, large amounts of young fish, shrimp and crabs would die before reaching their reproductive age. Less food would be available for adult fish and other higher forms of marine life, and therefore for human consumption. This is of particular relevance, as more than 30% of the world's animal protein for human consumption comes from the sea. One study of plankton estimates that a 25% reduction in ozone would lead to a 10% loss in primary production throughout the sunlit, biologically rich upper layer of the ocean, and a 35% reduction near the surface of the water.
Effects of the ozone hole in Antarctica have already been seen in some of the organisms. Most of the Antarctic organisms have a low tolerance for UV radiation since for most of the year, hardly any direct sunlight reaches the continent. With the reduced ozone in springtime, UV-B radiation has been able to penetrate the atmosphere with a higher intensity. Already, on the base of the Antarctica food chain, an impact has been felt. UV-B radiation has already reduced the plankton populations by between 6% and 12%. Consequently, species higher up have felt the impact. www.ozone-hole.org.uk/...
NASA has now found direct proof of the success of the Montreal protocol. Levels of ozone destroying stratospheric chlorine are declining and Antarctic ozone levels are recovering.
Measurements show that the decline in chlorine, resulting from an international ban on chlorine-containing manmade chemicals called chlorofluorocarbons (CFCs), has resulted in about 20 percent less ozone depletion during the Antarctic winter than there was in 2005 — the first year that measurements of chlorine and ozone during the Antarctic winter were made by NASA’s Aura satellite.
“We see very clearly that chlorine from CFCs is going down in the ozone hole, and that less ozone depletion is occurring because of it,” said lead author Susan Strahan, an atmospheric scientist from NASA’s Goddard Space Flight Center in Greenbelt, Maryland. www.nasa.gov/...
America has always been a nation of immigrants since the first American nations were built by immigrants who sailed and paddled their watercraft from Asia to the west coast of north America one island at a time. Immigration and diversity have brought fresh energy and new approaches to American life, leading to great leaps of scientific, economic, cultural and social progress.
The great burst of economic growth that America achieved in 1950s and 60s was built on the scientific and engineering genius of immigrants who escaped fascism in Europe in the 1930s and 40s. The “good old days” that many Americans look back on today happened because we built a powerful scientific research and engineering infrastructure at American universities and national laboratories to win World War II and the cold war with Russia. America’s progress in science and technology continues to be developed by immigrants today. But we all owe a debt of gratitude to one Mexican immigrant, Mario Molina, who’s scientific discovery and political activism literally saved the world.