Fare Thee Well, Sherry Rowland

by Bill Chameides | March 14th, 2012
posted by Erica Rowell (Editor)

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Initially dismissed, the findings by Sherry Rowland (R) and Mario Molina were verified by the National Academy of Sciences in 1976. In 1978 the U.S. banned CFC-based aerosols. (University of California, Irvine, Libraries’ Special Collections & Archives)

Frank Sherwood Rowland died on Saturday, March 10, 2012.

One of the great chemists of our time, Rowland followed in the footsteps of such giants as Antoine Lavoisier, Joseph Priestley and Justus Von Liebig who focused their research acumen on elucidating the composition of the atmosphere — a field we now call atmospheric chemistry.

Dr. Rowland accomplished much in the 60 years succeeding his doctoral studies at the University of Chicago. But his greatest achievement is almost certainly the work he and Mario Molina did on the role of chlorinated fluorocarbons (CFCs) in depleting the stratospheric ozone layer. Remarkable work. Sure, it won Rowland and Molina a Nobel Prize for Chemistry, but it also alerted the world to a mounting global environmental catastrophe. And it galvanized the international community to come to an unprecedented agreement to phase out CFCs and avert a dangerous depletion of the ozone layer. (Because CFCs and related chemicals act as greenhouse warmers, this agreement has also probably done more to mitigate global warming than any other policy thus far implemented.)

In awarding the Nobel Prize to Rowland, the Royal Swedish Academy of Sciences stated he (and Mario Molina and Paul Crutzen with whom he shared the award) “contributed to our salvation from a global environmental problem that could have catastrophic consequences.”

For me, the brilliance of Rowland and Molina’s work was the weaving together of two seemingly unrelated threads of scientific inquiry to arrive at a startling conclusion. Here’s how I remember it.

The Good, the Bad, and the Ugly
“Good” ozone (O3) occurs in the stratosphere where it protects us from the Sun’s harmful UV radiation. Bad ozone, found in the lower atmosphere or troposphere, is considered such because it acts as a greenhouse gas. Ugly ozone occurs at ground level where it is toxic to people, animals, plants. More on ozone here.

The CFC Thread

One strand of the thread pair began in 1928 with the work of Thomas Midgley, a mechanical engineer and chemist who along with Albert Henne invented the first CFC: dichlorofluoromethane.

By the mid-1930s, with air conditioners starting to make their way into American homes and refrigerator sales reaching eight million, CFCs (by then known as Freon, DuPont’s trade name for the chemical) had become the refrigerant of choice and a welcome replacement for the more toxic gases previously used in refrigeration, such as methyl chloride and ammonia.

By 1944, articles and ads in popular magazines made note of the coming use of Freons as a propellant in so-called aerosol spray cans (some 35 million of which were used by U.S. troops to guard against malaria-carrying mosquitoes in the South Pacific during World War II). Following the war Freon-propelled aerosol spray cans found their way into American homes, dispersing everyday needs from hair products and deodorants to bug spray. By the mid-1970s six billion spray cans were being produced annually worldwide.

This is about where the story shifts to James Lovelock, a scientist among a dying (some might say extinct) breed of scientists — Lovelock often works unaffiliated with any institution, funding his research with his own resources (no stinkin’ government grants for him!), and sometimes (decades before the two Steves, Wozniak and Jobs, tinkered around in theirs) inventing out of his garage or kitchen.

It was actually after not being able to score research dollars that in 1956-57 Lovelock invented (using his own resources) the electron-capture detector, a tool for detecting and quantifying the presence of trace amounts of a chemical, and in the late 1960s he began measuring the concentrations of CFCs in the atmosphere. Initial findings led him to believe the amount of Freons in the atmosphere was insignificant, but then together with a NOAA scientist named Lester Machta, he determined that the Freons from all those aerosol spray cans and refrigerators were leading to a significant atmospheric build-up of the stuff from Ireland to the Antarctic.

Lovelock’s observations raised at least two important questions: What was happening to atmospheric CFCs, and where do they eventually go?

The Chlorine-in-the-Stratosphere Thread

The other thread begins with a program launched in the early 1970s to determine if a commercial fleet of Supersonic Transports (SSTs) flying through the stratosphere between the United States and Europe would have an untoward environmental impact. Of special concern to this Climate Impact Assessment Program were the nitrogen oxides and water vapor emitted by the SSTs — potential depleters of the stratospheric ozone layer.*

And here’s where two other scientists Ralph Cicerone and Rich Stolarski, both from the University of Michigan, took another tangent. Because the exhaust of the soon-to-be-launched space shuttles would release chlorine into the stratosphere, they wondered if could that chlorine, like the nitrogen oxides and water vapor from the SSTs, would lead to the catalytic destruction of ozone? Stolarski and Cicerone
along with a graduate student (Stacey Walters) found that the answer was yes, but the amount of chlorine released by the proposed fleet appeared to be too small to pose a major threat.

Enter Rowland and Molina

It’s relatively easy for a scientist to succeed by following an individual thread of research to its ultimate conclusion. The great scientists take leaps instead of linear paths. In 1973, Rowland and Molina, both at the University of California, Irvine, realized the implications of these two research threads: (i) CFCs, which contain chlorine, were building up in the atmosphere with no apparent mechanism for their removal; and (ii) When in the stratosphere, chlorine catalytically destroys ozone. This prompted them to ask: Could CFCs diffuse upward into the stratosphere, be broken down, and release chlorine, thereby depleting the stratospheric ozone layer?

They went into the lab to find out, and the answer was yes. Rowland and Molina found that CFCs were inert in the lower atmosphere and would only break down when diffused upward into the stratosphere where they encounter ultraviolet radiation from the Sun. And that was a problem: the breakdown of the CFCs would release chlorine atoms which would spell bad news for stratospheric ozone.

When Rowland and Molina’s findings were published in the journal Nature in 1974, the chemical industry as well as some non-industry scientists largely dismissed it. It took another decade plus of research, as well as thousands of hours of meetings, briefings, and talks led by Rowland (and others), for the world to catch up and finally agree to get out of the CFC business — and start restoring the protective ozone layer.

Memories of Sherry

In 1974 I got lucky and landed a postdoctoral appointment working with Ralph Cicerone at the University of Michigan, just as the connections between chlorine, CFCs and ozone depletion were coming to light. Through my association with Ralph, I got to meet Sherry (as he was known) when still a very green Ph.D. Sherry immediately went out of his way to make me feel comfortable — familiar with my work, he encouraged me to keep at it.

Sherry Rowland and his wife, Joan, were married for nearly 60 years. (University of California, Irvine, Libraries’ Special Collections & Archives)

Like so many of my contemporaries in atmospheric chemistry, I came to look upon Sherry as a mentor, someone always available to provide guidance and advice when asked and, also important, willing to take the considerable time to write a letter of reference when needed. If I came to town, he made sure to find the time to visit. I’m pretty sure I wasn’t getting special treatment — helping out the younger members of his community was simply encoded in his DNA. In 1996 I had the honor of being a co-author on a paper with him.

Sherry was a superb scientist — a once-in-a-generation type. And I can think of few people who were more dedicated to science than Sherry. It was a rare experience to go to a scientific conference or workshop where he was not there taking copious notes and ready with wise and insightful comments to add to the discussion.

But he was also an incredible human being, gentle, kind, and thoughtful with a sardonic, somewhat self-deprecating sense of humor. Sherry’s wife Joan invariably accompanied him at meetings, and her joining us for lunch or dinner was always a treat. More often than not, they had either just come from or were headed to an opera at the Met — one of many passions they shared.

With his imposing six-foot-five stature, Sherry was also a pretty extraordinary athlete. He played semi-professional baseball in the ‘50s and varsity basketball as a graduate student at the University of Chicago. And his prowess on the court outlasted his varsity years by a long shot. One time during a break at a Gordon Conference Meeting in the 1980s, I drew the short straw of covering Sherry during a pick-up game. Despite the 20+ years of youth I had on him, he ate my lunch. Every time he got the ball, I would flail and pivot trying to keep him away from the hoop, pleading for “help” from my teammates. In my memory at least, every one of Sherry’s shots found nothing but net. Suffice it to say, we lost, by a lot. But the loss did not spell complete basketball ignominy: at the end of the game and so in keeping with the man, he turned to me with a warm smile and an outstretched hand to congratulate me on a “good game.” You know, I really believe he was sincere.

As scientists, we mourn the loss of a huge member of our community. Our hearts go out to Joan and their children.


End Note

* Elucidating the role of nitrogen oxides in removing stratospheric ozone led to Paul Crutzen’s share of the Nobel Prize for Chemistry in 1995.

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