How the question of scientific certainty shaped a global environmental crisis.
It was the middle of the night when Lee Thomas and Laurens Jan Brinkhorst broke their stalemate. Huddled together inside a Montreal bar, the pair might have toasted the common ground that had escaped them for so long.
Yet, neither trusted their harmony would last the night. Why would it? By the late summer of 1987, the decade-long ozone saga had seen plenty of false starts. With each year, new research generated fresh fodder for debate. More scientists, more experiments, more observations, more data, more papers.
Over time, a clearer picture emerged of the environmental danger posed by a one-time miracle chemical – and the North America-sized hole it ripped in the ozone layer.
But as science forged ahead, global policymakers like Thomas and Brinkhorst were stuck on the question of certainty, a slippery target that foiled compromise after compromise and kept scientists in perpetual search of an elusive smoking gun.
How could anybody be absolutely sure that CFCs caused the ozone hole? Was there enough data? What to make of the competing theories? Were the scientists, as one chemical executive suggested, Soviet agents hoping to destabilize the American economy?
Hope waxed and waned over the years, but every meeting ended without a deal. Until now. Could Thomas and Brinkhorst really have solved humanity’s first modern environmental crisis while hunched over a couple of beers at three o’clock in the morning?
Both were skeptical. “I’ll have to take this back to my member countries,” Brinkhorst said. He always says that, thought Thomas. “I’ll have to check with the White House,” he countered.
They didn't know it yet, but they'd just reached the most consequential environmental deal in modern history.
More than a decade earlier, Drs. Mario Molina and F. Sherwood Rowland, scientists at UC Irvine, raised the alarm that chlorofluorocarbons (CFCs) could harm the ozone layer.
That would be a big problem.
First, CFCs were widely used in refrigerators, air conditioners, and aerosol cans. Heralded for being nonflammable and nontoxic, CFCs enjoyed tremendous growth after World War II as they replaced the toxic and flammable chemicals historically used in refrigeration.
Second, once expelled into the atmosphere, CFCs linger for years. Even if CFC production stopped immediately, the CFCs already in the atmosphere would stay there for decades.
Third, CFCs break down into chlorine once in the stratosphere, and chlorine reacts catalytically with ozone. A catalytic reaction means one substance is unchanged after the reaction. While the ozone is destroyed, the chlorine atom is not, leaving it free to react with and destroy more and more ozone. A single chlorine atom can destroy a lot of ozone.
Finally, ozone absorbs most of the sun’s ultraviolet (UV) radiation. A thinning ozone layer lets more UV radiation reach the Earth’s surface, which scientists warned could increase skin cancer and eye cataracts rates, damage plants and agriculture, and destroy phytoplankton, an essential part of marine ecosystems.
Scientists predicted severe consequences in the next century if CFC production went unchecked. But in 1985, only 11 years after Drs. Molina and Rowland first raised the alarm, scientists in Antarctica discovered an ozone hole.
The threat wasn’t a century away. It was here now. And it tore a hole in the atmosphere.
Thanks to the efforts of Drs. Molina, Rowland, and countless others, scientists' understanding of the ozone layer and its intricate chemistry evolved rapidly starting around the middle of the century. By the 1980s, the evidence became harder and harder to ignore. CFCs poisoned the ozone layer, and the problem would worsen with time.
But not much happened for a long time.
Drs. Molina and Rowland spent years trying to convince policymakers to curb or eliminate CFCs, but they had only a theory to back their argument - a scientifically grounded theory, but still a theory. The ozone hole's discovery a decade later seemed to lay bare the consequences of unchecked CFCs. Yet, progress remained elusive.
The question of certainty lurked at every twist and turn of this story. Many policymakers were reluctant to regulate CFCs until they were absolutely certain they were a danger to the environment. And so the questions swirled. Must policymakers be certain that CFCs caused the ozone hole to justify regulating them? Was a CFC phaseout warranted even amidst some degree of uncertainty? Would waiting for absolute certainty be a case of too little, too late?
Absolute certainty, of course, is unachievable. Science relies on observation and experimentation to produce a body of evidence on which scientists draw conclusions. As the evidence evolves, so too must the conclusions.
Delegates around the world spent a decade debating what to do. The U.S., Canada, and Nordic countries argued for swift and decisive action. Europe, Japan, and others preferred slow and limited regulation, contending drastic steps were irresponsible absent decisive evidence implicating CFCs.
International consensus was crucial. Regardless of where they're produced or consumed, CFCs enter the global atmosphere and threaten the ozone layer above every nation. Unilateral regulation by one nation or a small group of nations wouldn't cut it.
By the late summer of 1987, after 13 years of globetrotting from conference to conference arguing the correct response to an unprecedented threat, the parties had agreed on the broad strokes. They would phase out CFCs. All that was left was to iron out the details.
So, on September 14, delegates descended upon Montreal to do just that. Brinkhorst represented Europe and Thomas the United States. Japan, the Soviet Union, Canada, and the Nordic countries played prominent roles too, all of them anticipating a global triumph.
But an eleventh-hour snag threatened to tank the deal. Europe wanted to count itself as one bloc, placing member states' CFC use into a single pool when measuring their compliance with the treaty's production and consumption limits. The United States preferred to count Europe as separate states.
For two days, negotiations dragged. The delegates broke at around midnight of the second day with hope for a deal nearly sunk.
That’s when Thomas had an idea that couldn’t wait. He tracked down Brinkhorst at a nearby bar where the European contingent had gathered. Over beers, Thomas suggested a compromise first proposed by the New Zealand delegation. They would count Europe as one bloc when measuring CFC consumption but as separate states when measuring CFC production. Countries that exhaust their production quotas couldn’t borrow from others who didn’t use all of theirs.
Brinkhorst agreed and, the next morning, so did their colleagues. All 197 UN member states eventually signed the Montreal Protocol on Substances That Deplete the Ozone Layer, which phased down and eventually eliminated CFCs and other ozone-depleting substances. To this day, it is the most successful international treaty of all time.
And it worked. The ozone hole is beginning to recover, and scientists estimate a return to pre-1980s ozone levels in the middle of the 21st century.
That’s the short story of how humanity solved its first modern environmental crisis.
The full story is better. It has supersonic jets, a hazy English countryside, the R.R. S. Shackleton, hairspray, a 70s era sitcom, a Nobel Prize, and that nagging question of scientific certainty.
But to tell this story, we need to set the stage with a little ozone science.
Part I: Early Concerns for Ozone Depletion
“I wanted to do pure science related to natural processes and therefore I picked stratospheric ozone as my subject without the slightest anticipation of what lay ahead.” - Dr. Paul Crutzen
The ozone layer is part of the stratosphere, located about 10km to 50km above the Earth’s surface. It contains most of the Earth’s atmospheric ozone, a gas molecule comprised of three oxygen atoms (O3) that absorbs most of the sun’s UV radiation via the ozone-oxygen cycle. Put simply, the ozone layer protects all life on Earth.
Here’s how it works.
UV radiation from the sun splits an oxygen molecule (O2) into two oxygen atoms (O + O).
UV radiation + O2 → O + O
Each oxygen atom (O) is then free to react with an oxygen molecule (O2) to form ozone (O3).
O + O2 → O3
UV radiation then splits an oxygen atom (O) away from the ozone molecule (O3). The free oxygen atom (O) can then react with an oxygen molecule (O2) to reform ozone (O3).
UV radiation + O3 → O2 + O
O + O2 → O3
Those last steps are the crucial part. It’s how ozone prevents much of the sun’s UV rays from reaching the Earth’s surface.
Scientists in the early 20th century didn’t yet understand the complex chemistry in the upper atmosphere. Charles Fabry and Henri Buisson had only just discovered the ozone layer in 1913, and nobody yet knew how manmade chemicals might disrupt it, nor did they fathom the tremendous consequences of doing so.
But interest swelled in the mid-20th century as scientists endeavored to better understand atmospheric chemistry and the ozone layer. Dr. Paul Crutzen was one of those scientists.
1969-70: First Hints of Manmade Ozone Depletion
Dr. Crutzen had only recently immigrated to Sweden when he saw the newspaper ad that would change his life.
It was 1958, and it he had recently arrived with his new wife in Gävle, a city along the Baltic coast a couple hundred miles north of Stockholm, and took a job at a construction firm. He had recently completed his mandatory military service and prior to that spent several years at a Dutch firm specializing in bridge construction.
The future was bright. He was in a new city enjoying a promising engineering career, and he'd welcome a baby girl at the end of the year. But he longed for academics.
Hardships had plagued his early elementary years in Amsterdam - the Nazis forced his class from their school building in 1941 and many of his classmates died during the famine of 1944-45 - but his schooling improved after the war.
He enjoyed math and physics and became proficient in three languages. When it came time to take final exams, however, a high fever hampered his performance and he failed to qualify for a university stipend. Rather than burden his family with the high cost of a university education, he chose the financially prudent path and studied civil engineering at a technical school before embarking on a career with European construction firms.
Shortly after arriving in Gälve, he read a newspaper ad announcing an open computer programmer position at the Department of Meteorology at Stockholm University. He applied and, despite possessing no programming experience, got the job.
Stockholm emerged as an early leader in meteorological science, and Dr. Crutzen used its powerful computers to help develop some of the earliest weather prediction models.
His employment allowed him to further his education too. “The great advantage of being at a university department,” he said, “was that I got the opportunity to follow some of the lecture courses that were offered at the university.”
He began pursuing a PhD in the mid-1960s and was asked to develop a model depicting how atomic oxygen (O), molecular oxygen (O2), and ozone (O3) are distributed in the atmosphere. The project required he dive into the scientific literature, exposing him to the work scientists were doing in the 1960s to critique old stratospheric models and develop new ones. The literature on ozone in particular piqued his interest, so he narrowed the scope of his project and began analyzing the prevailing ozone models.
"In this choice of research topic I was left totally free," he later remarked.
By the mid-1960s, many atmospheric models emphasized hydrogen-oxygen compounds as important to stratospheric chemistry. But when Dr. Crutzen analyzed those models he found they didn’t correctly explain ozone’s distribution in the stratosphere. He published a paper in 1969 suggesting instead that nitrogen played a crucial role in ozone layer chemistry.
If he were right, the consequences would be considerable. There are several manmade sources of nitrogen (think jet engines and fertilizers), so if nitrogen were to play a role in the ozone layer’s photochemistry, it would mean human activity could affect the ozone layer.
Dr. Crutzen wasn't ready to make such a claim in 1969. Or, more accurately, he couldn't. He was stuck. Lacking reliable measurements of stratospheric nitrogen, he couldn't analyze nitrogen’s role in the ozone layer's chemistry. Left with no other options, he recited the scientist's lament: further research is needed.
“The influence of nitrogen compounds on the photochemistry of the ozone layer should be investigated,” he wrote.
But soon, a stroke of luck would allow him to pursue his hypothesis.
Around the summer of 1969, Dr. Crutzen started working as a postdoctoral fellow at Oxford University’s Department of Atmospheric Physics. It was there that the head of his research group suggested he review data collected aboard a balloon a few years prior because it might give him the information he needed to test his nitrogen hypothesis.
Sure enough, it did. The balloon data revealed nitric acid (HNO3) in the stratosphere, and Dr. Crutzen used the data to discern nitric oxide (NO) and nitrogen dioxide (NO2) were also present.
He published another paper in 1970 suggesting a catalytic reaction between nitrogen oxides and ozone, meaning one substance is unchanged at the end of the reaction. In this case, nitrogen oxides destroy ozone, but the nitrogen oxides are unchanged at the end of the reaction, leaving them free to react with and destroy more and more ozone.
Here’s how it works.
When nitric oxide (NO) reacts with ozone (O3), it takes one of the ozone’s oxygen atoms to produce nitrogen dioxide (NO2) and an oxygen molecule (O2).
NO + O3 → NO2 + O2
When the nitrogen dioxide (NO2) then reacts with an oxygen atom (O), the NO2 gives one of its oxygen atoms (O), producing an oxygen molecule (O2) and nitric oxide (NO).
NO2 + O → NO + O2
So, we start and end with nitric oxide (NO). But we start with ozone and end without ozone.
Ozone is destroyed.
And because the nitric oxide is unchanged, it can react with and destroy more and more ozone.
Human activity could, Dr. Crutzen's research suggested, destroy stratospheric ozone and harm the ozone layer.
1971: Concern Over Supersonic Jets
A few months later, Dr. Crutzen came across a new report examining how planned supersonic jet programs might affect the atmosphere. Supersonic jets (think Concorde) release nitric oxide (NO) and travel at high altitudes. If Dr. Crutzen was right that nitrogen compounds could destroy ozone, then a fleet of jets delivering nitric oxide directly into the stratosphere could be a big problem.
And that’s exactly what Dr. Crutzen found when he analyzed the data from the report.
He calculated that the jets would emit enough nitric oxide into the stratosphere to create a global ozone crisis, but was dismayed to find the authors of the report unconcerned. They compared the effects of the nitrogen emitted by the jets to that of water vapor.
“I was quite upset by that statement,” Dr. Crutzen remarked years later. “Somewhere in the margin of this text I wrote ‘Idiots.’”
But others shared Dr. Crutzen’s concern. Dr. Harold Johnston warned in 1971 that nitrogen oxides emitted in the exhaust of supersonic jets could react with and deplete atmospheric ozone.
A few years later, a 1975 paper from the National Academy of Sciences agreed, warning “that an increase in the number of stratospheric airliners with present engines will diminish the amount of ozone in the stratosphere and consequently will increase the intensity of ultraviolet light at ground level.”
The alarm bells ultimately failed to ground the jets. Some, like the Concorde, operated for decades.
Still, “the new paradigm was set,” wrote Dr. Richard Stolarski, who would also contribute to ozone research. The ozone layer relies on a balance between ozone production and loss, “and human activities could influence this balance and affect ozone concentrations.”
It wouldn’t be nitrogen oxides or supersonic jets that landed Brinkhorst and Thomas in that Montreal bar debating the world’s response to the ozone crisis.
A different manmade substance would soon draw scientists’ scrutiny.
Part II: Linking CFCs to Ozone Depletion
“What is the consequence of society releasing something to the environment that wasn’t there before? Could you do any damage? Perhaps not, but we thought it was important to find out anyhow.” – Dr. Mario Molina
Home refrigeration became more affordable for the middle class towards the end of the 1920s. While iceboxes had been around since the middle of the previous century, the refrigerator marked a pivotal moment in middle class American living. Food stayed fresh longer. Risk of spoilage and foodborne illness dropped. Trips to the market became less frequent.
But early refrigerators relied on flammable and toxic chemicals. Ammonia, sulfur dioxide, and methyl chloride caused so many fires and chemical leaks that some households moved their refrigerators into the backyard.
It's unsurprising, then, that when Thomas Midgely, Jr. developed CFCs in the late 1920s, many considered the new refrigerant a godsend.
CFCs are neither toxic nor flammable. To prove it, Midgely inhaled a lungful of the chemical at the American Chemical Society's national meeting in 1930. Then he blew out a candle. Midgely survived. The room didn't catch fire. CFCs, which the refrigeration industry would market under the tradename Freon, were safe.
CFCs became the darling of the chemical industry in the next decades. Frigidaire, General Electric, and DuPont delighted as middle class families added refrigerators to their homes in droves during the 1930s and 1940s. By the end of World War II, the refrigerator had become a staple of the American kitchen.
Other industries adopted CFCs in their products too. Air conditioning, fire extinguishers, spray cans, asthma inhalers, and many other industrial and commercial products relied on CFCs. Aerosol cans alone jumped from 4.3 million cans in 1947 to 2.9 billion in 1973.
By the 1970s, as Dr. James Lovelock would soon discover, CFCs were everywhere.
1971-1973: CFCs Are Everywhere
As other scientists fretted over supersonic jets, Dr. Lovelock pondered the haze around his home in southern England.
A trained chemist with a Ph.D. in medicine, Dr. Lovelock began his scientific career at the beginning of World War II, a time when scientists often had to create the tools they needed for their research.
“In those days, it was customary to build, not buy, instruments,” wrote Dr. Lovelock in his book, “Homage to Gaia.”
Dubbed “a real-life Q from the James Bond movies” for his decades of work with MI-5, Dr. Lovelock invented the electron capture device (ECD) in the late 1950s.
The ECD analyzes the atoms and molecules present in a gas, allowing scientists to detect and identify the presence of specific chemical substances.
He called the invention “[p]erhaps the most important event in my life as a scientist,” and credited the ECD as “the midwife to the infant environmental movement.”
Dr. Lovelock’s ECD was 1000 times more sensitive than other devices used at the time, and it was particularly good at detecting manmade chemicals. Scientists would eventually use the ECD to measure traces of pesticides like DDT and pollutants like polychlorobiphenyls (PCBs).
It was the perfect tool to investigate the hazy air around his home.
Suspecting pollution as the culprit, he chose to measure CFCs because they do not occur from natural sources. They are entirely manmade.
Dr. Lovelock wanted to know if country air contained “some substance that originated unequivocally in an urban industrial region and which had no, or negligible, source in the countryside.”
Detected CFCs on hazy days in the countryside would implicate pollution as the source of the haze.
Dr. Lovelock began his experiment in Bowerchalke in southern England, measuring CFCs on hazy and clear days. He later took measurements from Adrigole along the coast of southwest Ireland.
Sure enough, he detected CFCs on hazy days, and not only in the wind coming from Europe but also in wind from the Atlantic.
CFCs were making their way across the ocean.
He later brought his ECD on a sea voyage to Antarctica via the R.R.S. Shackleton, detecting CFCs in remote areas of the Earth far from any CFC production or consumption.
“[T]he presence of [CFCs] in the southern hemisphere supported my speculation that these substances were distributed throughout Earth’s atmosphere,” he wrote.
Dr. Lovelock saw no danger in CFCs, though.
CFCs, he noted in his 1971 paper, were a good marker of air movement and wind direction,. He expressed no concern about CFCs’ global presence, even noting their safety to humans. A “gratuitous blunder,” he later admitted.
Nevertheless, his research would inspire two U.S.-based scientists to take a closer look at CFCs.
1974: Connecting CFCs to Ozone Destruction
Dr. Mario Molina arrived at the University of California Irvine in 1973 to study in Dr. F. Sherwood “Sherry” Rowland’s lab.
“Professor Rowland had a group doing very basic science at that time,” said Dr. Molina in 1996. “But as a postdoctoral student — that’s how I joined his group — we decided to move into a new field for us, which was the chemistry of the atmosphere.”
The year prior, Dr. Rowland had attended a conference in Fort Lauderdale where a lecturer described the results of Dr. Lovelock’s ECD tests.
“The starting point,” Dr. Rowland later recalled, “was the discovery by Jim Lovelock that the molecule, CCl3F, a substance for which no natural sources have been found, was present in the Earth’s atmosphere in quantities roughly comparable to the total amount manufactured up to that date.”
“To a chemist, this raised a challenge. Here was a new compound that had not been in Earth’s atmosphere before, and the question was, ‘What will happen to it?’”
Intrigued, he included CFCs on a list of suggested research projects for his new post-doctoral fellow. Dr. Molina chose CFCs.
“If human society is changing something important in the environment,” Dr. Molina said later, “human society should also find out whether there are any consequences. At the very least, I thought it was very bad manners just to release these chemicals without even knowing what would happen.”
So, Drs. Molina and Rowland set about trying to answer that question: what happens to CFCs once they’re released? Where do they go? How are they removed from the atmosphere?
They turned to the usual suspects:
Removal via rainwater
Removal via photolysis (destruction by sunlight)
Removal via oxidation (reaction where a molecule combines with oxygen)
CFCs are not water soluble and so removal via rainwater or the ocean was unlikely.
Photolysis would create a colored gas as the molecule interacts with sunlight, but CFC molecules were transparent, so they ruled out photolysis. Finally, CFCs don’t react with any oxidizing agents present in the atmosphere, so they ruled out oxidation too.
Suddenly it made sense why Dr. Lovelock found CFCs in the atmosphere at levels comparable to the total amount manufactured to date. Without a mechanism for removing them from the lower atmosphere, CFCs linger for decades before eventually making their way into the stratosphere. Once in the stratosphere, they encounter ultraviolet (UV) radiation, which finally breaks them apart and releases a chlorine atom.
That left an important question: What happens to the chlorine atom?
They recalled the work of Drs. Crutzen and Johnston, who warned of nitrogen oxides’ potential for catalytic ozone destruction.
Chlorine, Drs. Molina and Rowland suggested in a 1974 edition of Nature, also acts as a catalyst to destroy ozone.
Drs. Molina and Rowland were not the first to report the catalytic reaction between chlorine and ozone. That distinction goes to Drs. Richard Stolarski and Ralph Cicerone, who published their own 1974 paper just a few months before Drs. Molina and Rowland published theirs.
But Drs. Stolarski and Cicerone “had not associated chlorine with CFCs,” as Dr. Molina recounted later. “They were worried about chlorine from the Space Shuttle and volcanoes.”
Drs. Molina and Rowland pointed an accusing finger at CFCs, suggesting unchecked release of the chemicals would cause significant ozone depletion over the next several decades. Their abstract summarizes their findings:
Chlorofluoromethanes are being added to the environment in steadily increasing amounts. These compounds are chemically inert and may remain in the atmosphere for 40–150 years, and concentrations can be expected to reach 10 to 30 times present levels. Photodissociation of the Chlorofluoromethanes in the stratosphere produces significant amounts of chlorine atoms, and leads to the destruction of atmospheric ozone.
Here’s how it works.
The CFCs make their way into the stratosphere where they encounter ultraviolet (UV) radiation, breaking apart the CFCs. One of the products of that reaction is chlorine (Cl).
The chlorine atom (Cl) reacts with ozone (O3), stripping it of one of its oxygen atoms and forming chlorine monoxide (ClO) and an oxygen molecule (O2).
Cl + O3 → ClO + O2
The chlorine monoxide (ClO) then reacts with an oxygen atom (O), producing a chlorine atom (Cl) and an oxygen molecule (O2).
ClO + O → Cl + O2
The chlorine atom then reacts with another ozone molecule and the cycle restarts.
Start and end with chlorine. Start with ozone and end without ozone. Eventually, the chlorine reacts with another gas to break the catalytic cycle.
The Molina-Rowland theory set off a firestorm of science, skepticism, media interest, global conferences, and conspiracy theories.
Eventually.
1974: Those Were the Days…When a Hit Sitcom Taught Millions of Americans About the Ozone Layer
The world didn’t leap to its feet when Drs. Molina and Rowland published their paper.
“In hindsight, it was really not surprising that there was very little reaction initially,” said Dr. Molina. “We were talking about this invisible gas rising in the atmosphere to affect an invisible layer that was protecting us from invisible rays.”
The gravity of their theory was not lost on the scientists, though. "I came home one night, and my wife asked me how the work was going,” Dr. Rowland recalled. “And I said, 'Well, it's going very well — except it looks like it might be the end of the world.’”
Drs. Molina and Rowland embarked on a publicity campaign to spread word of their theory, citing a “responsibility to go public.” They presented at the convention of the American Chemical Society in September 1974, warning that CFCs could destroy 10% of the ozone layer over the next 50 years. And Dr. Cicerone joined Drs. Rowland and Molina in speaking before state legislatures, city councils, and even the U.S. Congress.
Their efforts paid off as the New York Times ran a front-page story on September 26, 1974, under the headline, “Tests Show Aerosol Gases May Pose Threat to Earth,” finally bringing the issue mainstream.
“It is the connection [to spray cans] – just the idea that a lot of people pressing these little buttons inadvertently were actually polluting the planet – that eventually caught the attention of the press,” said Dr. Molina.
Aerosol spray cans were a logical starting point to raise public awareness of the threat to the ozone layer. Air conditioners and refrigerators contained CFCs in their refrigerant lines, hidden away in some far-off crevice or attic, and only release the chemicals when the lines leak. On the other hand, aerosol cans release CFCs every time someone squeezes the nozzle of their hairspray or deodorant.
Connecting the issue to spray cans personalized the issue for millions of people. Among them, the writers of a hit television show.
By 1974, All In The Family had been the number one show on television for years.
The show featured Archie and Edith Bunker, who live in Queens, New York, with their daughter, Gloria, and her husband, Mike.
Writers used the generational gap between conservative Archie and his liberal, counterculture daughter and son-in-law to talk about the issues of the time, including the environment.
All In The Family was the most-watched television show in the 1974-75 season, viewed by over 20 million households.
An episode that aired in late October of that year – just a few months after Drs. Molina and Rowland published their paper – wedged a heavy-handed ozone lesson into an argument between Gloria and Mike as they discuss whether to have a child:
Mike: Here. Right here. This is a killer.
Gloria: Oh, so now my hairspray is a killer.
Mike: Yeah, your hairspray, my deodorant, all spray cans. I read that there are gases inside these cans, Gloria, that shoot up into the air and can destroy the ozone.
Gloria: What’s the ozone?
Mike: Ozone is a protective shield that surrounds the Earth and protects us against ultraviolet rays, and you know what they can do?
Gloria: Yeah, they can give you a sunburn.
Mike: Sure, when the ozone’s there, but when it’s all gone you can get skin cancer. And God knows what it can do to the plants and crops.
Gloria: Alright, Michael, let’s compromise. You let me have a baby and I’ll let you have my hairspray!
Mike: Gloria, some scientists are saying that in ten years at the rate the ozone’s going, this world’s going to be in big trouble.
The aerosol industry credited the episode with turning the public against CFCs and aerosol cans.
For its part, the DuPont Company – one of the world’s leading CFC producers – pledged to end CFC production if proof arose linking CFCs to ozone depletion. A nearly full-page advertisement in the June 30, 1975, edition of the New York Times repeated the promise.
But the science, DuPont argued, was uncertain and the push for regulation premature. In other words, the issue lacked the scientific certainty needed to stop making CFCs.
The ad, which reads more like an advertorial, says:
The industry was being “prejudged.”
Aerosols were “under a cloud of presumed guilt.”
The “ban now – find out later” approach was “a disturbing trend.”
The U.S. should not act “before the full facts are known.”
DuPont was “trying to find the truth.”
“There is time to gather information and make a reasoned decision.”
DuPont ran another ad in an October 3, 1975, edition of the journal Science accusing Drs. Molina and Rowland of making “a number of assumptions about the way the upper atmosphere behaves.”
(Drs. Rowland and Molina responded a couple months later, denying making any such assumptions.)
The industry went to great lengths to discredit the scientists, especially Dr. Rowland.
“There were times when the industry tried to make it appear that Sherry Rowland was just a maverick out there in the boonies and he had come up with this crazy scheme that was flawed,” said U.S. senator Dale Bumpers, who held hearings on ozone depletion in the mid-1970s.
“They just sort of made it look as though he was off the deep end, that he was an oddball.”
One industry executive even accused the scientists of working for the Soviets. Criticism of CFCs was “orchestrated by the Ministry of Disinformation of the KGB,” claimed the president of one aerosol manufacturer.
1978: The U.S. & Others Ban CFCs in Aerosol Cans
There were, of course, plenty of questions to answer.
The Molina-Rowland theory hadn’t observed ozone loss in the atmosphere. It only presented a rationale for why and how CFCs could threaten the ozone layer.
The DuPont ad in the Times made that point clearly: Perhaps we should say “the lack of evidence” – for that is what exists – on both sides of the controversy. Hypothesis lacks support. Claim meets counterclaim. Assumptions are challenged on both sides. And nothing is settled.
Even the authors weren’t 100% certain of what they had found.
“We just thought that it was sufficiently important that we had to find out more about it,” Dr. Molina said later.
“When you first sort of get into a new problem, you’re not sure what the outcome is going to be, so you’re always taking risks. In this case, the risk was even larger, because we were suggesting that our findings had to lead to some changes in industry.”
Those changes in industry would come rather quickly.
The National Science Foundation created the Interagency Task Force on Inadvertent Modification of the Stratosphere (IMOS) to explore the Molina-Rowland theory and suggest policy solutions. The IMOS recommended regulating “fluorocarbon uses” if an ongoing National Academy of Sciences (NAS) study supported such measures. It did.
In the late 1970s, amid the growing public awareness of the ozone problem, the United States – along with Canada, Sweden, Denmark, and Norway – banned CFCs in aerosol cans. The U.S. ban took effect in 1978.
Aerosol cans were a major contributor to CFC release, and the ban scored a victory for the scientists and environmentalists pushing for regulation.
But CFCs were still allowed in refrigerants, air conditioning, and many other applications, and only a handful of nations acted.
“The CFC problem was partially solved,” recalled Dr. Rowland, “but only for use as a propellant gas, and then only in the United States, Scandinavia and Canada, because the other countries didn’t follow suit on the aerosol propellant controls.”
The atmosphere is a global issue. Every nation exists underneath it and within it. What one nation does – or doesn’t do – affects every other nation.
Dr. Lovelock discovered that CFCs spread globally, including to the most remote regions of the Earth where CFCs had never been made or consumed.
Should a handful of nations stop CFC production, the production lost in those nations would shift to other nations that had not banned CFC production. And CFCs made and consumed in those nations would affect all others.
Half measures or partial participation wouldn’t cut it.
1985: The Vienna Convention
The aerosol ban of 1978 addressed the threat closest to the public (spray cans), and, as if satisfied the problem was solved, the issue faded from the public eye and lay dormant for years.
But scientists, policymakers, and environmentalists pushing for a larger and more permanent solution didn’t let the issue die. Talks between nations continued into the 1980s.
An early rift over CFC regulation pitted the U.S., Canada, Finland, Norway, and Sweden – dubbed the Toronto Group because they had first met in Toronto – against Europe and Japan.
The Toronto Group nations favored swift and decisive regulation to phase out CFCs. Europe and Japan favored a measured approach that would only cap production, a proposal the Toronto Group nations opposed largely because the proposed cap was well above Europe’s current level of production and, thus, ineffectual.
The regulation issue became an impasse, but the parties did agree on other things. At a March 1985 meeting in Vienna, the delegates agreed to the Vienna Convention for the Protection of the Ozone Layer.
The Vienna Convention did several things:
It encouraged nations to adopt legislative or administrative measures to protect the ozone layer.
It created the Ozone Research Managers, a group of atmospheric scientists who meet every three years to create a report on the state of the ozone layer.
Nations agreed to share research related to ozone depletion.
The Vienna Convention’s non-binding provisions lacked the teeth needed to adequately regulate CFCs and fix the ozone problem.
But it was a start.
Mostafa Tolba, executive director of the United Nations Environment Programme, called the Vienna Convention “the first global convention to address an issue that for the time being seems far in the future and is of unknown proportions.”
It represented “the anticipatory response so many environmental issues call for – to deal with the treat of the problem before we have to deal with the problem itself.”
As it had 10 years earlier when Drs. Molina and Rowland first presented their theory, the debate over scientific certainty stood as an obstacle to a more robust agreement in Vienna.
Many favoring no or modest regulation (i.e., production caps instead of a full CFC phaseout) argued the science was incomplete. Regulation in the face of such scientific uncertainty, they argued, was unwarranted.
Environmentalists and many scientists argued the opposite: immediate action was not only warranted, but essential.
For one, scientific certainty is a fallacy. It's unachievable. Scientists endeavor to understand the world, but they'll never be certain of their understanding. They research, observe, experiment. Over time, they amass evidence to support conclusions, challenge others, and hopefully achieve a greater understanding of their subject.
Insisting on absolute certainty that CFCs cause ozone depletion would be perpetually futile.
But even achieving something like reasonable certainty could take years or decades – time the ozone layer couldn’t afford given the accelerating pace of CFC production. What degree of certainty is needed to act? How much scientific evidence would it take, and at that point, will it be too late?
The Molina-Rowland theory explained how manmade chemicals like CFCs could affect the ozone layer. The issue, however, lacked a clear and vivid picture of ozone loss. No proof, as it were.
But unbeknownst to negotiators in Vienna, a clear and vivid picture was materializing.
At a remote research station on the bottom of the Earth, a small group of scientists had been wrestling for years with what to do about their strange ozone readings.
Part III: The Antarctic Ozone Hole
“As I remember it, there was no real eureka moment in the discovery, more a combination of pieces falling into place.” - Jon Shanklin
Joe Farman suspected his Dobson spectrometer was broken.
The ozone measurements it returned over Halley Bay, Antarctica, in October 1981 were too low.
Farman joined the British Antarctic Survey (BAS) in 1956 and soon began recording ozone levels above Antarctica. Scientists had been erecting ozone stations around the world since the 1930s, and by the early 1980s Halley Bay Station was one of dozens around the globe.
Farman dutifully recorded ozone measurements for decades, devoting himself to what some “well-meaning friends” questioned as “so mundane a branch of scientific inquiry.”
Despite toiling away at his isolated research station in Antarctica, though, Farman was familiar with the Molina-Rowland theory. He knew it suggested CFCs could deplete stratospheric ozone, and he knew CFCs had spread through the global atmosphere, including in Antarctica.
He realized what his readings might suggest: CFCs caused the drop in ozone that scientists predicted.
But these readings were way too low.
CFCs weren’t supposed to cause significant ozone depletion until sometime in the next century. And even then, nobody predicted a drop this dramatic.
He blamed his spectrometer and ordered a new one.
When his new spectrometer returned way-too-low results the next year, he questioned whether he might be detecting abnormalities directly above the Halley Bay station. He moved the instrument to another part of Antarctica but got similar results.
Still, Farman wasn’t ready to go public. He needed to be sure the ozone loss his instruments detected was real.
When the Dobson spectrometer again returned abnormal measurements in October 1983, Jon Shanklin, who worked with Farman at the BAS, sent NASA a letter asking if the agency’s satellite data was consistent with the BAS team’s unusual ozone readings.
NASA’s Nimbus 7 satellite had measured ozone levels via its solar backscattered ultraviolet experiment (SBUV) and total ozone mapping spectrometer (TOMS) instruments since 1978.
If something were amiss, surely NASA’s satellites would detect and report it.
1981-1985: NASA (Sort of) Misses the Ozone Hole
The story goes that NASA’s satellite did detect unusual ozone levels above Antarctica, but its computers automatically threw out the abnormal data because it was outside the expected range.
But that isn’t quite true.
When the satellite detected abnormal ozone levels in September and October 1983, NASA’s computers excluded it from analysis but did not discard it.
It wasn’t until the summer of 1984, nearly a year after it was collected, that NASA scientists finally analyzed the abnormal satellite data.
Drs. Pawan Kumar Bhartia and Richard McPeters of NASA’s Goddard Space Flight Center blamed the delay on “slow computers and the lack of digital data links to transport data.” The Internet, after all, was in its nascent stages and not yet widely available even among scientists and government agencies.
NASA set out to confirm its unusual satellite data with data collected on the ground, and so turned to the World Ozone and Ultraviolet Radiation Data Centre (WOURDC).
Many research stations measuring stratospheric ozone reported their data to the WOURDC, which compiled and published it in “Red Books,” providing researchers a running log of ozone data from around the world.
But when NASA scientists turned to the Red Books to confirm their satellite data, the Red Books showed normal ozone levels, seeming to confirm NASA’s satellite data was an error.
Yet, NASA’s data was right. So was Farman’s.
Two teams had unexpected data suggesting a big problem in the ozone layer. One had ground data it tried to confirm with satellite data; the other had satellite data it tried to confirm with ground data.
Missed connections and bad luck got in their way and delayed both sides from announcing their discovery.
Most significantly, Farman was not submitting his data to the Red Books in the early 1980s.
Had he been, then when NASA turned to the Red Books to confirm its satellite readings, the Red Books would have confirmed the abnormal satellite data, clearing the way for NASA’s scientists to report what they found.
But Farman’s ozone measurements from Halley Bay Station weren’t there.
“We just sort of felt that what's the point of sending off raw data like that,” Farman said later, “when we know perfectly well that by the time we comb through it and made all the adjustments it's going to be changed again?”
“I guess we have to sort of apologize in that sense.”
Instead, the Red Books data NASA found was from a station showing normal ozone readings, leading NASA to conclude its data was wrong. But, in another unlucky break, that station’s data was incorrect and later retracted.
The Red Books data was bad. Not NASA’s.
And that letter Shanklin sent NASA asking for help confirming Farman’s abnormal readings?
It did find its way to NASA, but his request went to researchers measuring ozone via ground, balloon, and rocket instruments. Not satellites.
Shanklin’s request never made it to anybody at NASA’s Goddard Space Flight Center where scientists were analyzing the satellite data.
In October 1984, NASA received data directly from NOAA’s South Pole Station corroborating its abnormal satellite data. Finally convinced the significant ozone depletion they detected was real, NASA scientists submitted an abstract to share their discovery at a conference scheduled for August 1985.
But Farman scooped them.
May 1985: The British Antarctic Survey Reports the Ozone Hole
Discovering the ozone hole was a slow burn.
Farman could have raced to announce his unusual ozone readings in 1981. He was, after all, sitting on blockbuster news that he discovered significant ozone depletion decades before anybody expected it.
But publishing and being wrong would be disastrous. It would destroy the British Antarctic Survey’s credibility and jeopardize the stingy annual funding keeping Halley Bay Station afloat.
Worse, skeptics of the Molina-Rowland theory would relish in a big, splashy announcement that wound up being wrong.
And the scientists who warned for years of an impending ozone crisis? They would certainly be irked at witnessing their skeptics latch onto an erroneous announcement to bolster the argument that dire warnings of ozone loss were premature.
So, Farman approached his strange readings with skepticism and entertained all kinds of explanations – a bad spectrometer, electromagnetism over Halley Bay, volcanic eruptions.
Fearful of revealing the data too early, he even stopped a graduate student from publishing his doctoral dissertation because it included Halley Bay Station’s 1982 data.
“What convinced the team” to finally publish, wrote Shanklin, “was a graph plotting the minimum 11-day mean, which clearly showed that the spring decline was systematic.”
Shanklin called himself a “minor player in the end result,” calling his “persistence in looking at the data” his main contribution. Brian Gardiner, another scientist at the BAS, did “the essential quality control on the data,” Shanklin wrote.
Finally comfortable enough to publish, Farman, Gardiner, and Shanklin announced an ozone hole over Antarctica in May 1985.
Data from Halley Bay and the Argentine Islands – thousands of miles from Halley Bay – showed ozone loss of 30 to 40 percent. And because the BAS regularly measured trace gases like CFCs, they also reported rising CFC levels over Antarctica.
A chart juxtaposing rising CFCs with declining ozone produced a striking visual of the Molina-Rowland theory’s core suggestion that CFCs destroy stratospheric ozone.
The Farman paper stirred up the atmospheric science community, but it would take months for news to reach the broader public.
NASA scientists revisited their satellite data in the months after Farman published his findings and confirmed ozone had dropped by as much as 40 percent every year between 1979 and 1985 during the Antarctic spring, consistent with Farman’s readings.
An image created using the agency’s satellite data would become an enduring visual of the ozone hole.
The NASA team shared the image at a couple of conferences in August 1985. Dr. Rowland, who attended one of the conferences, sent the image to the New York Times, which published it on November 7, 1985, announcing to the public that a “hole” had formed in the ozone layer.
Over the next several weeks, media around the world reprinted the Times article under a slew of headlines, thrusting the ozone issue back into the popular consciousness.
“Antarctica Ozone Loss Confirmed,” read the Arizona Republic.
“Data Show Ozone Loss Quickening Over Antarctica,” warned the Fort Worth Star-Telegram.
“Antarctic Ozone Shield Thinner,” reported The Age in Melbourne, Australia.
Evidence linking CFCs to ozone depletion was building, but an ozone hole wasn’t proof. There was plenty of science left unsettled.
The Pittsburgh Post-Gazette struck at the uncertainty of the ozone hole’s origins: “Reduction of ozone in atmosphere continues to puzzle scientists.”
Meanwhile, in Boulder, Colorado, Dr. Susan Solomon was grappling with just that uncertainty: why and how did an ozone hole form over Antarctica of all places?
1985-1987: Debating the Origins of the Ozone Hole
Dr. Solomon studied under Dr. Johnston at UC Berkley and Dr. Crutzen at the National Center for Atmospheric Research (NCAR) in Boulder where she completed her graduate work. After graduating, she joined the NOAA Aeronomy Lab, wrote a textbook, and worked on a stratospheric model with a colleague.
And she wasn’t even 30.
Selected as a peer reviewer of the Farman paper before it was published, she “looked very carefully through the paper,” she said in an interview about a decade later, and “concluded pretty quickly that it had to be right.”
She was unconvinced, however, of Farman’s theory of what caused the ozone hole.
Farman suggested that Antarctica’s cold, dark winters promote the formation of chlorine reservoirs. He proposed that the reservoirs release the chlorine each October as spring arrives, leading to the catalytic reactions that Drs. Molina and Rowland warned about.
Dr. Solomon disagreed. She pointed instead to heterogeneous reactions.
Most ozone depletion models at the time relied on homogenous reactions. That is, gases react with other gases. A heterogeneous reaction, on the other hand, is one where gases react with a solid or liquid.
Whereas a homogeneous reaction relies on gases encountering other gases, which happens somewhat randomly, a fixed solid or liquid surface would allow molecules to encounter each other more frequently, speeding up the rate at which they react.
And because Farman detected rapid ozone loss far outpacing that predicted by the prevailing homogeneous reaction models, Dr. Solomon felt heterogenous reactions could explain the rapid ozone loss.
Dr. Rowland and Dr. Donald Wuebbles had previously explored heterogeneous reactions in a laboratory setting using a glass surface. They found heterogenous reactions could cause ozone depletion of 32 percent, similar to the 30 to 40 percent depletion Farman reported over Antarctica.
But there were no surfaces in the middle of the stratosphere. Clouds – tiny droplets of water and ice – don’t typically form at those elevations.
Except in Antarctica.
Temperatures in the atmosphere above Antarctica are low enough in the winter to allow polar stratospheric clouds to form 80,000 feet above the Earth.
“A unique feature of the Antarctic lower stratosphere is its high frequency of polar stratospheric clouds, providing a reaction site for heterogeneous reactions,” Dr. Solomon wrote along with Drs. Rowland, Wuebbles, and Rolando Garcia in a paper published in June 1986.
Dr. Solomon suggested that polar stratospheric clouds provide an icy surface on which chlorine compounds like CFCs react rapidly to form massive amounts of ozone-destroying chlorine (Cl).
Enough to create the ozone hole.
The chemical industry was unconvinced of Dr. Solomon’s heterogenous reaction theory.
Richard Barnett, chairman for the industry lobbying group Alliance for Responsible CFC Policy, commented on the uncertainty in a quote published by the New Yorker in 1986.
“Although the observed reductions in the ozone over the Antarctic region are real, the ozone levels return to near normal soon after the October springtime begins, and no plausible mechanism has been proposed to explain this phenomenon.”
Scientists too were unconvinced. In fact, theories of what caused the ozone hole were plentiful.
A New York Times article in November 1985 named several of them: CFCs, sunspot cycles, volcanic eruptions, a local change in atmospheric circulation, and a long-term trend of widening variations in ozone levels.
Dr. Mack McFarland, an atmospheric scientist at DuPont, later reflected on the competing theories. “There was insufficient information to distinguish among theories attributing the cause to changes in meteorology, chemistry related to solar cycle effects, or chemistry related to increasing concentrations of man-made compounds containing chlorine or bromine.”
Dr. Solomon also recalled the debate in an interview years later.
“In late 1985, there were basically three different credible theories” of what causes the ozone hole, she said.
There was a theory blaming nitrogen oxides “in association with solar maximum coming down out of the thermosphere into the stratosphere.” Dr. Solomon had done her thesis on this topic and understood it well. But “as more data became available [the nitrogen oxides theory] pretty much got shown to be incorrect.”
There was also “the dynamical idea” on which “a number of authors…had papers published trying to propose different ways, different processes that might cause the dynamics of the stratosphere to change in such a way to reduce the ozone dramatically.”
And then there was “the idea of chlorine chemistry being involved,” as Drs. Molina and Rowland hypothesized. Dr. Solomon’s heterogenous reaction hypothesis contributed to the chemical theory.
But there was no smoking gun. Nothing catching CFCs in the act or proving any of the other theories.
1986-1987: NOZE I & NOZE II Find CFC-driven Ozone Depletion
Dr. Solomon, with specialties in atmospheric chemistry and dynamics and well-versed in the prevailing ozone hole theories, was a natural choice to lead the National Ozone Expedition (NOZE).
A joint effort of NOAA, NASA, and the National Science Foundation (NSF), NOZE would send scientists to Antarctica to record and measure the chemical compounds present in the stratosphere. Its mission was to gather data that would enable scientists “to discriminate between the theories” and put to rest the debate over what caused the ozone hole.
NOZE I would not succeed.
Dr. Solomon and the NOZE scientists arrived at McMurdo Station in August 1986 and soon detected large amounts of chlorine monoxide (ClO) amidst declining ozone levels.
The inverse measurements – high chlorine monoxide, low ozone – lent support to the Molina-Rowland theory of chemistry-driven ozone depletion, and the NOZE team concluded chemistry “probably plays an important role in the development of the Antarctic ozone hole.”
But other scientists revolted.
For one, the scientists on the NOZE expedition, including Dr. Solomon, supported the chemical-cause theory ahead of the mission. Many of the scientists who supported the nitrogen and dynamics theories felt left out and accused the NOZE team of bias in reaching its conclusion.
“By November the controversy over the origins of the ozone hole had become a furor,” read an article in The Atlantic recounting the debate.
So, Dr. Solomon would lead a second NOZE expedition the following year in search of more definitive evidence.
Whereas the first NOZE expedition used ground instruments and balloons to collect data, NOZE II would fly high-altitude jets right into the ozone hole to measure ozone and other gases.
This presented several new obstacles.
First, they needed a jet.
It had to be capable of flying slow enough to record accurate measurements. A jet traveling too fast would fail to collect accurate readings.
NASA provided an ER-2 high-altitude plane, a descendent of the U-2 spy plane. The ER-2 traveled at subsonic speeds, theoretically slow enough for scientific instruments on board to record reliable measurements. The expedition also received a DC-8 aircraft that would fly at lower altitudes.
Second, the jets needed a runway.
Chile, the southernmost nation on Earth whose residents worried about their proximity to the ozone hole, allowed the ER-2 and DC-8 to take off from its airport in Punta Arenas. NASA even repaved the runway on its dime to give the jets a smooth takeoff.
Third, the jets needed pilots.
The mission would be exceptionally dangerous for the pilots. If something went wrong and the pilot had to bail above Antarctica or the Southern Ocean, rescue was next to impossible, and they faced near certain death.
They chose combat veterans of the Vietnam War for their experience flying single-pilot, manual aircraft, which was similar in nature to the ER-2.
Fourth, the scientists needed a new instrument.
It had to be capable of measuring chlorine monoxide at high speeds. Even at the ER-2’s subsonic speeds, the rush of airflow was too much for existing scientific instruments to record reliable data. Further, the ER-2 carried a single person, and the pilot couldn’t fly the plane and operate a scientific instrument.
The instrument would need to be mounted on the jet, operate automatically, and handle a tremendous rush of airflow.
The NOZE team turned to Dr. James Anderson. Dr. Anderson had developed instruments to measure chlorine monoxide before but never attached to a jet.
His team created an instrument capable of slowing air speed from 200 to 20 meters per second, allowing it to measure chlorine monoxide in a more manageable air sample.
On August 23, 1987, the third ER-2 flight – Dr. Anderson’s instrument failed on the first two flights – recorded high levels of chlorine monoxide but stable ozone levels.
This was expected.
Farman recorded ozone loss in September and October during the Antarctic spring. Ozone loss wouldn’t be expected in August as the sun was just beginning to emerge at the end of Antarctic winter.
A flight three weeks later, however, discovered something completely different.
On September 16, the instruments aboard the ER-2 found lots of chlorine monoxide and an enormous drop in ozone. Subsequent flights also revealed a negative correlation between chlorine monoxide and ozone.
In other words, the more chlorine monoxide you have, the less ozone you have.
This was the smoking gun.
The data provided striking visuals of the sharp decline in ozone from winter to spring. The side-by-side graphs provide a striking visual comparing chlorine monoxide and ozone on August 23 near the end of the Antarctic winter and on September 16 at the beginning of the Antarctic spring.
As the sun peaks out over the polar clouds at the end of winter, its ultraviolet rays strike the clouds and set off the reactions that create chlorine, which over the next several weeks reacts with and destroys ozone to produce the ozone hole every September and October.
The NOZE II data would convince most people that CFCs create the ozone hole.
But on September 16, delegates gathered 10,000 miles away in Montreal didn’t know the NOZE team had finally acquired evidence clearly linking CFCs to ozone depletion.
For two years after Farman first reported the ozone hole, delegates persisted in their pursuit of an international ozone treaty, meeting at conferences around the world trying to strike a deal.
Still painting the debate over ozone, CFCs, and regulation was the question of certainty - or more accurately, the type and amount of evidence and degree of certainty needed to act.
In the years since discovery of the ozone hole, the scientific community remained at odds over what caused it. If the scientists couldn’t agree, then what business did policymakers have in singling out CFCs and forcing industry to phase out the chemicals?
Yet, by the time they arrived in Montreal, the delegates were nearing a deal. In fact, just as the ER-2 returned its stunning data on September 16, they were clearing the last hurdle to an international treaty, the end of a road they had started down nearly 15 years earlier.
Part IV: The Montreal Protocol
“EPA does not accept as a precondition for decision, empirical verification that ozone depletion is occurring.” - Lee Thomas
Lee Thomas joined the EPA in 1983 as Acting Assistant Administrator for Solid Waste and Emergency Response.
No stranger to wordy titles, Thomas came to the EPA after serving as Executive Deputy Director and the Associate Director for State and Local Programs and Support of FEMA and, prior to that, Director of the Division of Public Safety Programs for the Governor of South Carolina.
In 1985, President Ronald Reagan pegged Thomas as EPA Administrator.
Thomas took over an agency still struggling to regain public confidence following Anne Burford Gorsuch’s tumultuous tenure in the early 1980s. Gorsuch – her son, Neil, became a U.S. Supreme Court Justice in 2017 – cut the EPA’s budget, shrank its workforce, and later dismissed concern for the ozone layer as a “scare tactic.”
A Congressional investigation of improper use of the Superfund – a program established to clean up sites contaminated with toxic waste – would doom her tenure as EPA chief. She resigned in 1983 after it came to light she withheld funds to clean up a toxic waste site in California to harm the U.S. Senate campaign of former Governor Jerry Brown.
Hoping to restore trust in the agency, President Reagan appointed as her successor William Ruckelshaus, who served as the EPA’s first administrator at the agency’s founding in 1970.
Ruckelshaus led the EPA until April 1973 and then served briefly as FBI Director before being named U.S. Deputy Attorney General. He resigned as Deputy AG in October 1973 after refusing to carry out President Richard Nixon’s directive to fire the Watergate special prosecutor. The incident became known as the Saturday Night Massacre.
Decidedly more environmentally conscious than his predecessor, Ruckelshaus refocused the agency on its core mission and ferried the agency through the scandals of the Gorsuch era. But he could not restore the agency’s budget.
Ruckelshaus resigned at the end of President Reagan’s first term, and Thomas was appointed his successor.
1985-1987: The CFC Debate at Home and Abroad
The Lee Thomas era at the EPA began in February 1985 just as the ozone crisis was surging back into the national consciousness.
A month after he began his stint as EPA chief, the U.S. and other nations agreed to the Vienna Convention. Two months after that, Farman and the British Antarctic Survey reported the ozone hole.
The science was building, and so was the public’s awareness of the ozone problem. NASA’s satellite image of the ozone hole became ubiquitous, appearing in newspapers and evening newscasts around the country. Soon, Dr. Solomon would lead the NOZE missions to Antarctica where they’d gather data definitively linking CFCs to the ozone hole.
But from the start, even before the ozone hole discovery or the NOZE missions, Thomas saw the ozone problem as solvable and urgent.
He told an EPA workshop shortly after taking over the agency, “Several aspects of the situation suggest we may need to act in the near term to avoid letting today’s ‘risk’ become tomorrow’s ‘crisis.’”
He would soon buck the Reagan administration’s anti-regulation streak in proposing that the U.S. and other countries take immediate action to curb CFC production.
An early stalemate in the CFC debate was, predictably, what to do with them.
The U.S., Canada, and Nordic countries – dubbed the Toronto Group – adopted a more aggressive stance on CFCs and banned their use in aerosol cans. In the 1980s, they insisted on a CFC phaseout. Europe and Japan preferred less restrictive measures and favored a production cap.
The Toronto Group had dropped its insistence on a phaseout to encourage Europe and Japan to agree to the Vienna Convention, but the old bone of contention quickly reemerged at an international conference in Rome.
“We were devastated,” said John Hoffman who represented the EPA at the conference in May 1986. “I realized that in aggressively pursuing an international aerosol ban we were pursuing a policy that was absolutely suicidal.”
In pushing the aerosol ban, Europe felt the U.S. was digging up an issue it thought to be buried.
Even back home, the idea of a CFC phaseout was far from unanimous. Members of the American scientific and policymaking communities disagreed on how best to address the ozone problem.
At a Senate sub-committee hearing in June, Senator John Chafee warned, “The scientific evidence is telling us we have a problem, a serious problem.”
Senator Chafee, who served as chairman of the sub-committee, recalled the acid rain debate from a few years prior, warning the committee not to fall into the same trap of hiding behind research as “a substitute for action.”
Dr. Rowland also testified, chastising world governments for their “attitude of prudent caution toward interfering with the chlorofluorocarbon industry.”
The Reagan administration, meanwhile, largely endorsed a cautious approach to the ozone issue.
Bob Watson of NASA argued it wasn’t clear whether the ozone hole predicted future ozone depletion or if it was the result of conditions at the South Pole. William Graham, Deputy Director at NASA, cautioned it could take another 10 years of research before enough is known about the ozone problem to justify any specific action.
A notable exception to the Reagan administration’s restraint, however, was Thomas.
Echoing his statement to an EPA workshop the previous year, Thomas advocated for “some intervention” to curb the buildup of manmade gases, including CFCs, “even while there is scientific uncertainty.”
But Thomas was not ready to act alone. Any solution to the CFC problem had to be global, and he wasn’t ready to give up hope of an international treaty.
The lone bright spot of the contentious workshop in Rome was a dinner held for the delegates at a villa on the outskirts of the city. The conversation drifted away from CFCs, giving the delegates an opportunity to relate to each other personally.
Hoffman and Richard Benedick, the Deputy Assistant Secretary of State who represented the U.S. in the Vienna Convention talks, intended to apply the lessons from Rome as they planned the next conference set for September 1986 in Leesburg, Virginia.
Thomas gave the greenlight to adopt a more congenial atmosphere in Leesburg, which would feature a barbeque and square dancing. But most significantly, the U.S. backed off its insistence on a CFC phaseout, giving the delegates a clean slate on which to base negotiations.
The Leesburg conference was decidedly more successful as the delegates agreed on two important fundamentals: chlorine molecules from CFCs were affecting the ozone layer and the risk was of sufficient concern to warrant action.
“At that meeting,” Hoffman said, “I knew there was going to be a protocol. It was only a question then of what the percentage reductions were and exactly what structure the protocol had.”
Even the chemical industry teased a softened stance.
The Alliance for Responsible CFC Policy now encouraged world governments to limit future CFC growth.
The about-face came as the industry faced several realities.
First, the satellite rendering of the ozone hole laid bare the harm wrought by unchecked CFCs.
Second, CFC alternatives were within reach. Recalling its pledge to phase out CFCs should evidence of their harm emerge, DuPont said it could find alternatives within five years.
Third, the industry understood regulation was inevitable. They could adapt or be forced to adapt.
Finally, CFCs were a small part of most chemical companies’ business. It made little sense to spend big dollars defending a product accounting for a fraction of revenue.
The industry never shed its defiance, though, and still argued there was no imminent threat to the ozone layer.
In a letter to customers, the company cited science’s inability to establish a safe level of CFC production and the unlikelihood of any near-term resolution. It called its new tack “prudent” and “precautionary” as scientists work “to provide policymakers with better guidance.”
Hope for an agreement swung high and low in the months following the Leesburg conference.
In October, Hoffman presented Thomas a report on the devastation expected from sustained ozone depletion. The report warned of millions more skin cancers and eye cataracts in the next decades, devasting effects on forests and crops, and rising smog. It convinced Thomas to pursue an aggressive phaseout strategy despite predicted resistance from Europe and Japan, who still favored a production freeze.
“From a scientific point of view,” Thomas explained, “a phaseout was the correct goal because these were offending chemicals. All this discussion they were having about a freeze seemed to blur the fact that this was the ultimate goal.”
The State Department and EPA revealed its CFC control plan on November 5, 1986, aiming for a short-term CFC freeze, long-term phaseout, and a periodic review of ozone depletion to consider further action.
At a meeting in Geneva in December, the U.S. proposed an immediate freeze on CFC production and a gradual phaseout of 95% of CFC emissions over the next 10 years. Europe and Japan accepted a freeze but rejected a phaseout.
A few months later in Vienna, the U.S. proposed 10- to 14-year phaseout. This time, Europe gave a little by countering with a 20 percent reduction in certain CFCs, but the Europeans still wouldn’t accept a complete phaseout.
By spring, the delegates tentatively agreed to a short-term freeze and 50% phaseout - 20% in the near-term and an additional 30% at a future date.
“I will tell you where that fifty percent came from,” said Thomas in an interview decades later. “It really came to me from my discussions with industry groups. I became convinced they clearly had substitutes that they could develop.”
The industry, Thomas said, just needed to know there would be a market for them. “If you committed to a phase-out, at least that fifty percent, they would know there was going to be a market.”
But the chemical industry grew alarmed.
Their enthusiasm the previous year assumed regulations would stop at a production freeze with caps on future growth, not a phaseout.
The CFC companies weren’t ready to lay down, though, and they had friends in high places who opposed the regulations and downplayed the risk posed by ozone depletion.
One such ally was Interior Secretary Donald Hodel, a regulation-averse veteran of the Reagan administration who served as Secretary of Energy before the president pegged him to run the Interior Department.
May 1987: The Personal Protection Plan
The Department of the Interior was an odd participant in the ozone debate.
Tasked with managing federal lands and natural resources and overseeing programs relating to Native Americans, the Interior Department justified its involvement in ozone conversations because it oversaw more land than any other executive department. The increased UV light from ozone depletion, it argued, would affect its land more than others.
David Doniger of the Natural Resources Defense Council didn’t buy it.
Himself an advocate of the phaseout strategy, Doniger suspected Secretary Hodel was arguing behind the scenes against a phaseout, favoring instead the production freeze proposed by Europe.
So, when Doniger got word that Secretary Hodel planned to argue a “personal protection” strategy to deal with the ozone crisis and a resulting increase in ultraviolet radiation, he went to the press.
The personal protection plan would have Americans wear sunscreen, sunglasses, and hats to protect themselves from worsening UV rays.
The plan became a laughing stock.
The Atlanta Constitution broke the story in late May, and other papers quickly jumped on it:
Wall Street Journal: Advice on Ozone May Be: “Wear Hats and Stand In The Shade”
Washington Post: Administration Ozone Policy May Favor Sunglasses, Hats
Los Angeles Times: Suggests Wearing Hats, Sunscreen Instead of Saving Ozone Layer: Hodel Proposal Irks Environmentalists
A New York Times story began, “Finding an eye-catching way to ridicule the Secretary of the Interior, Donald P. Hodel, is this week's sport in the House of Representatives.”
Rep. Thomas Downey appeared on the House floor wearing a hat and sunglasses. “These are the new weapons,” he said.
Rep. James Scheuer hauled cutouts of animals donning sunglasses and hats onto the House floor because “animals, too, would need ‘personal protection’ from ultraviolet rays under Mr. Hodel's approach,” wrote the Times.
Political cartoonists didn't hold back either. On June 3, Herblock published a cartoon portraying a dog, cat, cow, and a couple ducks sporting hats and sunglasses as a man doses some plants - also wearing hats and sunglasses - with suntan oil.
Hodel protested the media’s portrayal of his position.
"What really mischaracterizes my position is to say that I have a definite position, and I don’t," Hodel said. "I don’t believe we ought to box in the president."
He advocated for personal protection only in the absence of an international agreement, he claimed.
"If the United States has to go it alone,” he said, “one of the things that ought to be considered is that there would be very limited reductions in worldwide CFC production, so the ozone problem would continue and we’d face the existing medical problems as well as additional problems."
"If you’re concerned about health, then we need to be concerned about behavior today. We need to notify people of the hazards of sunlight."
Hodel said that U.S. negotiators had yet to specify what would need to be included in any international agreement, and conceded, "If (the president) choses an option different from mine, I couldn’t be critical."
But the damage was done.
The personal protection plan blunder helped swing support behind the U.S. negotiating team’s position to phase out CFCs rather than accept a production freeze.
Responding to Hodel’s personal protection plan, Thomas said, "The most effective way to solve the problem is through an international agreement to significantly reduce the amount of ozone-depleting chemicals emitted worldwide."
On June 5, the Senate passed a resolution supporting U.S. efforts seeking an international agreement to freeze CFC production at 1986 levels and cut CFC production by at least 50 percent.
A cabinet meeting that included President Reagan gave Thomas and the U.S. negotiators their marching orders. They were to seek a 95 percent reduction in CFC production, but accept 50 percent.
The vote of confidence in the phaseout strategy put Thomas on solid ground ahead of the Montreal conference scheduled for September.
"I, by far, had the strongest position going into Montreal than any other minister there," he said, "and I had it from the president of my country. And very few of the others had that strength."
September 1987: Finally, Success in Montreal
Delegates met again in Montreal on September 14, 1987.
Thomas and the U.S. negotiating team picked up discussions with Laurens Jan Brinkhorst and his team representing Europe.
A lifelong Dutch politician who would go onto become a Deputy Prime Minister of the Netherlands two decades later, Brinkhorst served as the European Commission’s Ambassador to Japan from 1982 to 1987.
He resigned the ambassadorship upon being appointed Director General for Environmental and Nuclear Safety on January 1, 1987, plunging him into a senior role representing Europe in the ongoing CFC negotiations.
Still leery of an extensive phaseout, Europe had come around to a freeze followed later by a partial phaseout. The U.S., though, threw an unexpected wrench into the discussions.
The United States now demanded that for the protocol to become binding, countries representing 90 percent of worldwide CFC consumption would have to ratify it. Prior agreements put the number at 60 percent.
The new U.S. demand threatened to sink the protocol.
Another sticking point emerged too. The delegates disagreed about how to count the European Community – a predecessor to the European Union – for purposes of measuring compliance with the treaty they were negotiating.
Europe wanted to count itself as one bloc. The U.S. wanted to count it as 12 separate states.
If counted as one bloc as Europe preferred, member states could borrow from each other’s quotas, allowing one state to decrease CFC production but another to increase.
The U.S. opposed this.
“We worked late into the evening trying to work through major issues,” said Thomas.
“I remember when we broke one evening, we were totally at odds. A small group was trying to get to a final conclusion. The U.S. was on this side, and the European Union was on that side.”
But after breaking around midnight, Thomas and his team had an idea.
“So, we ended up finding Laurens Jan Brinkhorst…at a bar, having a beer. And so he and I had a beer together, and we ended up coming to a conclusion on how we both could support a provision.”
They agreed to count Europe as a single bloc when measuring CFC consumption but as separate states when measuring CFC production. Member states couldn’t increase production by borrowing quotas from other member states that decreased theirs.
The U.S. also agreed that countries representing 66 percent of worldwide CFC consumption would be needed to ratify the treaty, backing off its previous stance of 90 percent.
“I said, ‘If it appears you are prepared and I am prepared, we will meet at eight o’clock in the morning, and go in, and we will both support this,’” recalled Thomas.
So, we both met at eight o’clock the next morning, we supported it, and we were able to get through that major impasse and move forward.”
The Montreal Protocol on Substances That Deplete the Ozone Layer was ratified on September 16, 1987, the same day the NOZE II expedition first recorded that dramatic drop in ozone.
The Montreal Protocol became effective on January 1, 1989, and, along with the Vienna Convention, became the first United Nations treaties to achieve unanimous ratification.
The delegates agreed to freeze CFC consumption and production at 1986 levels and cut CFCs 20 percent by 1994 and another 30 percent by 1999.
Acknowledging that developing nations may lack the resources to quit CFCs as quickly as developed nations, the treaty adopted a tiered approach that set different commitments and deadlines for developed and developing nations.
Developing nations could increase production no more than 10 percent per year for the next 10 years. The delegates even created a multilateral fund to help developing nations comply with the regulatory commitments.
The protocol also stipulates that the parties meet every year, and an Ozone Secretariat assists and supports the parties by organizing the conventions, helping to implement the decisions made at the conventions, managing and distributing data, and providing the public with information on protecting the ozone layer.
And it worked.
Present Day: Signs of Ozone Hole Recovery
Drs. Molina, Rowland, and Crutzen shared the 1995 Nobel Prize for Chemistry for their work on ozone depletion.
The Nobel announcement also acknowledged the contributions of Dr. Harold Johnston, Dr. James Lovelock, Dr. Richard Stolarski, Dr. Ralph Cicerone, Joseph Farman and colleagues, Dr. Susan Solomon, and Dr. James Anderson.
Because of their efforts – and the efforts of countless others in science, industry, and government – the ozone hole is starting to recover.
A 2018 NASA study provided the first evidence attributing ozone layer recovery to human intervention.
Still, the size of the Antarctic ozone hole fluctuates annually.
Enough long-lasting, ozone-depleting chemicals remain in the atmosphere to create an ozone hole every year, peaking around September and October.
“Its size and depth are governed to a large degree by the meteorological conditions particular for the year,” says the World Meteorological Organization (WMO).
Warmer temperatures in the stratosphere lead to smaller ozone holes, while cooler stratospheric temperatures lead to larger ones.
“Colder-than-average temperatures in the Antarctic stratosphere created ideal conditions for destroying ozone this year,” NASA said of the larger-than-average 2018 ozone hole, “but declining levels of ozone-depleting chemicals prevented the hole from as being as large as it would have been 20 years ago.”
A year later, the 2019 ozone hole was the smallest on record “due to warmer stratospheric temperatures,” noted Paul Newman, chief scientist for Earth Sciences at NASA's Goddard Space Flight Center. “It’s not a sign that atmospheric ozone is suddenly on a fast track to recovery.”
And, wouldn’t you know it, the 2020 ozone hole was the longest-lasting and one of the largest on record, and the 2021 ozone hole was also above average.
“We see some wavering as weather changes and other factors make the numbers wiggle slightly from day to day and week to week,” said Newman of the 2022 ozone hole, which was smaller than the year before.
“But overall, we see it decreasing through the past two decades. The elimination of ozone-depleting substances through the Montreal Protocol is shrinking the hole.”
Scientists estimate global ozone will return to 1960 levels around 2060. Ozone levels in Antarctica may not return to 1960 levels until the end of the century.
But the ozone hole will recover.
Epilogue
“This global problem has also shown us that different sectors of society can work together – the scientific community, industry, environmental organizations, government representatives and policy makers – to reach international agreements.” - Dr. Mario Molina
The Montreal Protocol was a big deal.
For 13 years, nations grappled with the question of scientific certainty.
At what point was there enough evidence to act?
Was it when Drs. Molina and Rowland first theorized that CFCs could harm ozone? When Farman and NASA confirmed an ozone hole over Antarctica? When Dr. Solomon’s NOZE mission sent jets into the ozone hole seeking the answers that many demanded?
The chemical lobby, policymakers, politicians, and scientists argued if and how to react. Environmentalists pleaded for regulation. Journalists wrote stories. Public interest swelled, waned, and swelled again.
Through it all, the science never stopped.
Drs. Molina and Rowland continued researching CFCs and ozone. Farman measured the ozone above Halley Bay. Dr. Solomon trekked to the bottom of the Earth seeking answers. And countless others lent their scientific curiosity to the ozone problem.
Their diligence paid off.
By the late 1980s, nations around the world decided there was enough evidence to phase out CFCs and stop the ozone depletion threatening the planet.
All 197 United Nations member states eventually ratified the Montreal Protocol. For many, it’s a reminder that nations can act in unison to solve big problems when it’s in their interest to do so.
Today, the Montreal Protocol is still a big deal.
The parties continue to meet every year. In the 1990s, they sped up the CFC phase out and designated other ozone-depleting substances for phaseout.
In 2016, they agreed to phase down HFCs, a compound that initially replaced CFCs because they don’t harm ozone. But HFCs are a considerable greenhouse gas, and some estimate that phasing down their production avoided a half-degree Celsius of further global temperature increase.
The ozone story begs the question: What else can we fix – and when should we fix it?
Recommended Reading & Watching
There’s even more to this story.
Check out these articles, documentaries, and books for more on the ozone hole and the worldwide campaign to fix it.
“Not with a bang but a pfffft?” A lengthy New York Times article published at the end of 1975, it lays out the early part of this story as fully as any other, taking readers from Dr. Crutzen’s and Dr. Johnston’s earlier work to the then-recent theory presented by Drs. Molina and Rowland.
“In the Face of Doubt” by Paul Brodeur. The author’s second article on the ozone crisis revisits the issue a decade after his first. Published in 1986 as news of the ozone hole reinvigorated the debate, Brodeur laments the lack of action to curb CFCs and address the ozone problem.
Stratospheric ozone depletion by Dr. F. Sherwood Rowland. A journal article published in 2006 in Philosophical Transactions of the Royal Society B in which Dr. Rowland recounts the story of the ozone hole.
Ozone Crisis by Sharon Roan. The author begins in 1973 as Drs. Molina and Rowland first warn CFCs could harm the ozone layer and ends with the signing of the Montreal Protocol just a couple of years before the book was first published in 1989. It features a detailed look at the negotiations to regulate CFCs.
Between Earth and Sky by Seth Cagin and Philip Dray. Starting with Midgely’s invention of CFCs in the 1920s, the authors tell a story fully capturing the stakes of Drs. Molina and Rowland’s theory and the efforts to negotiate an international agreement. Published in 1993.
Ozone Hole: How We Saved the Planet. A PBS documentary that tells the story of the ozone hole. First aired in 2018.
References
Effort was made to cite within the text the source of each publication, journal article, website, or book referenced in telling this story. Below is a selected bibliography of sources referenced for background or quotations.
Bhartia, P. K., & McPeters, R. D. (2018). The discovery of the antarctic ozone hole. Comptes Rendus Geoscience, 350(7), 335–340. https://doi.org/10.1016/j.crte.2018.04.006
Cagin, S., & Dray, P. (1993). Between Earth and Sky: How CFCs Changed Our World and Endangered the Ozone Layer. Pantheon Books.
Channel 4 and PBS. (2018, August 18). Ozone Hole: How We Saved the Planet. broadcast.
Clough, K., & Butler, H. (2012, April 19). Interview with Lee Thomas, EPA's 6th Administrator. other. Retrieved from https://www.epaalumni.org/history/video/interview.cfm?id=28.
Kellogg, D. (1997, September 5). Oral History Interview with Susan Solomon. other. Retrieved from https://opensky.ucar.edu/islandora/object/archives:7756.
Lovelock, J. (2000). Homage to Gaia: The Life of an Independent Scientist. Oxford University Press.
Molina, M., & Rowland, F. S. (2000, December). Cfc-Ozone Puzzle: Lecture. The John H. Chafee Memorial Lecture on Science and the Environment 1st National Conference on Science, Policy and the Environment. Washington, DC; National Academy of Sciences.
Norton, S. (1999, October 11). Oral History Interviews - Joseph Farman. other. Retrieved from https://www.aip.org/history-programs/niels-bohr-library/oral-histories/33753-1.
Roan, S. L. (1989). Ozone crisis: The 15-Year Evolution of a Sudden Global Emergency. John Wiley & Sons.