F. Sherwood Rowland, 1927-2012
On March 10, atmospheric chemist “Sherry” Rowland of the University of California-Irvine died in the company of his son and his wife of almost 60 years. Rowland became prominent in the 1970s after warning that common chemicals would destroy ozone 10 kilometers above Earth, exposing life to a shower of harmful radiation.
While exploring how chlorofluorocarbons (CFCs) degrade after being released into the atmosphere, Rowland and graduate student Mario Molina realized the CFCs would float to the upper atmosphere, be cleaved by sunlight, and release chlorine that would destroy ozone through a chain reaction.
(Ozone contain three oxygen atoms; most oxygen molecules contain two oxygens.)
By intercepting cancer-causing UV radiation, ozone in the stratosphere allows life to exist on Earth. Significant damage to this ozone would cause an epidemic of human and animal cancer, and likely damage plants as well.
This alarming prospect was not popular in industries that relied on CFCs, but it sparked a long and largely successful effort to restrict and then ban production of the chemicals.
And although Rowland never retreated from his findings, his calm, charismatic personality helped his cause. Ralph Cicerone, now the president of the National Academy of Sciences, recalls collaborating with Rowland on CFCs. “We talked on the phone nearly every day. I considered Sherry to be my best friend, and over time I learned that many people considered him to be their best friend, too. In the midst of the debates over CFCs, he never exaggerated the dangers, always cited the science, and treated other people with dignity and respect.”
What must a scientist do?
According to the University of California-Irvine’s press service, Rowland knew his results mattered far beyond the lab: “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. Entire biological systems, including humans, would be at danger from ultraviolet rays.”
At the time, scientists were studying the health implications of ozone-bearing smog in the lower atmosphere, but few people knew or cared about “good” ozone in the stratosphere.
The sudden notoriety of CFCs had a certain irony: The chemicals were invented in the 1920s at General Motors, maker of Frigidaire brand refrigerators, as a stable, non-toxic alternative to the ammonia and explosive propane used in air-conditioning and refrigeration.
CFCs later were used to expand plastic foam, clean electronic parts, and propel paint and deodorant in the mushrooming aerosol-spray business.
Antarctic ozone hole, 2011
They publish lest we perish!
Rowland’s 1974 study1 ignited a long squabble over CFC production. Aerosol Age, the spray-can industry’s trade journal, implied that Rowland was a member of the Soviet KGB who wanted to destroy capitalism!
CFCs remained a back-burner issue, however, until the British Antarctic Survey discovered an alarming absence of ozone in 1985. The “Antarctic ozone hole” gave the theoretical worry sudden significance, and as the industry gradually found substitutes for CFCs, the ozone hole stopped expanding.
Today, as we watch the faltering response to global warming, it’s comforting to recall that the ozone threat prompted prompt collective action: The Montreal Protocol, a treaty to restrict CFC production, became effective in 1989 and has since been tightened after further alarm over ozone destruction, and 196 nations — essentially all of them — have signed the original Protocol. Production of ozone-depleting substances has fallen by more than 95 percent.
“CFCs were extremely useful compounds and their use was pervasive,” says Rudy Baum, editor in chief of C&EN (Chemical and Engineering News). “Although manufacturers maintained that there would be dire consequences if the use of CFCs were restricted or banned, it became clear pretty quickly that alternatives could be found in most cases.”
And yet ozone is still a problem, as shown by a 40 percent drop in Arctic ozone in the winter of 2010-2011. Continuing destruction is blamed on the stability of CFCs and the fact that the replacements, while less damaging, still destroy ozone. “Ozone can be thought of as a patient in remission, but it’s too early to declare recovery,” said Susan Solomon of the University of Colorado.
Not bounded by the lab walls
Nonetheless, the Montreal protocols are considered an epochal case of planetary preventive medicine, and Rowland, Molina and Paul Crutzen, who also worked on CFCs, were awarded the 1995 Nobel Prize for Chemistry.
But for 10 or 15 years, Rowland had played the role of maverick — speaking outside the laboratory about the importance of what he had found inside it. It’s not a comfortable role for many scientists; many find it safer to stay in the lab and let others figure out what to do with their results.
Jonathan Fink, vice-president of research at Portland State University, says “The culture of science is pretty deep in terms of how we are trained. Most science grad students are taught to focus on being the best at something, rather than thinking about the application of what they do to society.”
All along, Rowland explained the science and gently reminded us of our stake in an intact ozone layer. He continued to study atmospheric chemistry, mentor younger scientists, and show by example how scientists could speak responsibly about what their results mean for the rest of us.
Somehow, Rowland managed to fight his battles without making enemies, at least outside the industries that had inadvertently begun calamitous destruction of ozone.
Why do scientists like Rowland speak out? “Because they’re scientists and scientists are addicted to facts and what facts tell them,” says Baum. “I knew Sherry Rowland pretty well — I was the West Coast correspondent for C&EN from 1991 to 2004 … he was a gracious, dignified, reserved individual, certainly not a rabble-rouser. But he knew that his science was solid and that it told him that humans were doing something that would have catastrophic consequences if they didn’t stop. So he spoke out. Simple as that.”
A new disaster unfolds
Even before the Montreal Protocol was signed, climate scientists were starting to warn that carbon dioxide in the atmosphere would enhance the greenhouse effect and trigger global warming. In testimony to the U.S. Senate in the torrid summer of 1988, NASA climatologist James Hansen linked rising temperatures to rising levels of greenhouse gases from fossil fuels.
The debate over global warming and climate change had begun, and going public put Hansen in much the same position as Rowland had occupied 15 years before. Via email, Hansen credited Rowland and atmospheric scientist Don Hunten as “role models… . They showed that it was possible to do first-rate science and also uphold our responsibility to make clear the implications of our research for society.”
Until then, Hansen had been a well-regarded but faintly visible NASA expert in planetary atmospheres. He had studied Venus, where an atmosphere choked with carbon dioxide produces a “runaway greenhouse effect” that raises the surface temperature to 460° C.
After making news in 1988, Hansen retreated from the public discussion of warming, but in the early 2000s, as temperatures continued to rise, he began to speak up again. In 2005, after the Bush White House tried to muzzle him, he went public with a vengeance.
Why? Journalist Mark Hertsgaard, who has written extensively about global warming and repeatedly interviewed Hansen, says he “thinks like a scientist, believes if you find the information, and present it properly, the truth should carry the day. I think he came out of hibernation in 2005 only because he felt he had to. He looked around and saw that the information alone was not carrying the day.”
Hansen’s regular emails combine climate facts with political opinions for a broad audience. For example, a recent commentary argued that “Scientists attempt to communicate, but are flummoxed by the ability of the profiteers to manipulate democracies. The scientific method (objective analysis of all facts) is pitted against the talk-show method (selective citation of anecdotal bits supporting a predetermined position).”
On Aug. 29, 2011, Hansen was arrested at the White House with hundreds of others protesting the Keystone XL tar-sand oil pipeline. Tapping such a vast reservoir of carbon, Hansen believes, will bring us that much closer to a “tipping point” on greenhouse warming. “Now we’ve got the spectacle of one of the world’s foremost climate scientists getting arrested and urging others to get arrested,” says Hertsgaard. “This is way beyond speaking out.”
Hertsgaard, a native of Minnesota, says it’s “very hard for [Iowa native] Jim Hansen the person to speak out.” In the Midwest, Hertsgaard says, “it is just not seemly to draw attention to yourself or bring up a topic that is likely to discomfort others. … but it’s not corny to talk without irony about the importance of doing the right thing.”
The glacially slow acceptance of continental drift
Until German scientist Alfred Wegener traveled the world in the early 1900s, geologists thought the continents were static. But Wegener found evidence for what he called “continental drift”:
In 1912, Wegener proposed a theory of continental drift, but could not explain a mechanism for that movement. The theory “was not very well accepted, particularly in this country,” says Ziegler. “The American Association of Petroleum Geologists voted on the theory of continental drift and voted it out of existence.”
In the 1950s, new studies began to vindicate Wegener:
By the late 1960s, continental drift, renamed “plate tectonics,” had produced a new and integrated picture of the planet that explains earthquakes, tsunamis and volcanoes.
Ziegler ran a mapping project at Chicago that “picked up where Wegener left off, making maps for various periods of geological time. Wegener was a hero to us,” he says.
The scientific culture
A fully indoctrinated scientist is chary of talking much beyond the lab, Hertsgaard says. “Many scientists very much frown on taking the public agitator role, and that’s another tribute to Hansen’s courage. He was prepared not only to take brickbats from the Exxon-Mobil front groups, but to endure the judgment of his own peers, who said ‘That’s not what scientists do.’ He remembers that he’s not just a scientist, he’s a human being too.”
Despite the successful example of the Montreal Protocol, the global warming problem is vastly harder to solve, says Baum of C&E News. “The scale of fossil fuel use is several orders of magnitude larger …. Humans consume between 80 million and 90 million barrels of petroleum every day, and that represents only about a third of the fossil fuel that is consumed.”
Finally, while the specter of cancer caused by increased UV radiation is unsettling, “people actually like the warmer conditions, at least for now,” Baum wrote. “We didn’t have a winter in Washington, D.C., this year … and people loved it.”
So will the environmental victory over CFCs that started with Rowland and Molina be mirrored by serious action over global warming? Maybe not, says Spencer Weart, a long-time chronicler of warming. Comparing the ozone battle to the fight over global warming “is like comparing a single battle to a world war. Ozone depletion (once the ozone hole was detected) was clearly an urgent problem, with a straightforward solution. But with global warming, it’s hard for people to worry much about something that seems remote in space and time — isn’t it just a problem for polar bears and our grandchildren?”
Slowing warming “will require wholesale changes in our entire world economy,” Weart says. “And that must begin with government regulation of the fossil fuels industry, the largest concentration of economic power the world has ever seen. The pushback has been fierce, beginning with industries that suspected their profits would be restricted, and extending to people who fear governmental threats to their freedom.”
Rowland was once libeled as a Soviet spy, but “Scientists who have put themselves into politics like Jim Hansen … have been subject to ad hominem attacks: crude vilification and direct threats far beyond anything that Rowland experienced.”
Hansen and his colleagues, says Weart, “have persisted nevertheless. For the logic of their scientific understanding forbids them from keeping silent about the dangers they foresee.”
— David J. Tenenbaum
Terry Devitt, editor; S.V. Medaris, designer/illustrator; Molly Simis, project assistant; David J. Tenenbaum, feature writer; Amy Toburen, content development executive
- Stratospheric sink for chlorofluorocarbon methanes: Chlorine atom catalyzed destruction of ozone, Mario Molina & F.S. Rowland, Nature, 249:810 ↩
- Maxwell Boykoff, 2012, ‘2000-2011 USA Newspaper Coverage of Climate Change or Global Warming’, University of Colorado at Boulder, Center for Science and Technology Policy Research ↩
- NOVA remembers Sherwood Roland ↩
- Biography of Mario Malina ↩
- Nobel Prize in Chemistry: 1995 ↩
- Chemistry explained: Freons ↩
- When refrigerators warm the planet ↩
- Health effects of overexposure to the sun ↩
- James Hansen TED Talk: Why I must speak out about climate change ↩
- The NY Times: Global warming and climate change ↩
- The Amoeba People present “The Posthumous Triumph of Alfred Wegener” ↩
- Synposis of plate tectonics ↩
- History of plate tectonics ↩