Scientists vs. Hairspray: The Battle for the Ozone Layer

0:00 Speaker 1: Hello, dear listeners. Most disasters in history arrive loudly, cities burn,

0:05 Speaker 1: volcanoes erupt, armies march across borders, and entire civilizations collapse

0:11 Speaker 1: in dramatic fashion. But occasionally, a threat to humanity begins quietly,

0:17 Speaker 1: buried inside a research paper, hidden within chemical equations, and

0:22 Speaker 1: unnoticed by nearly everyone outside a laboratory. The realization that

0:27 Speaker 1: human beings might be damaging the very sky above them

0:30 Speaker 1: began exactly this way, not with explosions or disasters, but

0:35 Speaker 1: with two chemists asking a simple question about a group

0:38 Speaker 1: of seemingly harmless chemicals. On March twentieth, nineteen seventy four,

0:44 Speaker 1: two atmospheric chemists Mario Molina and F. Sherwood Rowland published

0:49 Speaker 1: research that sounded almost unbelievable at the time. Their work

0:53 Speaker 1: suggested that chemicals widely used in refrigerators, air conditioners, and

0:57 Speaker 1: aerosol spray cans might be slow full destroying the ozone

1:01 Speaker 1: layer high above Earth's surface. The idea seemed almost absurd

1:05 Speaker 1: to many people, after all, how could something as small

1:09 Speaker 1: as a spray can possibly influence the chemistry of the

1:12 Speaker 1: entire atmosphere. But Molina and Roland had discovered a chemical

1:16 Speaker 1: chain reaction that suggested something far stranger was happening, a

1:20 Speaker 1: process where human made molecules could drift silently into the

1:24 Speaker 1: upper atmosphere and begin dismantling the planet's protective shield molecule

1:30 Speaker 1: by molecule. To understand why this discovery was so alarming,

1:35 Speaker 1: we need to travel about fifteen miles above the surface

1:38 Speaker 1: of Earth into the stratosphere. There, spread across a thin

1:43 Speaker 1: band of atmosphere exists the ozone layer. Ozone is a

1:47 Speaker 1: form of oxygen made of three atoms bonded together instead

1:51 Speaker 1: of the usual two. Although this layer is extremely thin,

1:56 Speaker 1: if compressed to ground level it would be only a

1:59 Speaker 1: few millimeters There, it performs one of the most important

2:02 Speaker 1: jobs on the planet. It absorbs the majority of the

2:06 Speaker 1: Sun's harmful ultraviolet radiation before it reaches the surface. Without it,

2:13 Speaker 1: life on Earth would look dramatically different. Plants would struggle

2:18 Speaker 1: to grow, marine ecosystems would collapse, and the risk of

2:22 Speaker 1: skin cancer would skyrocket. For billions of years, this thin

2:27 Speaker 1: atmospheric shield had quietly protected life without anyone noticing it existed.

2:33 Speaker 1: The chemicals that concerned Molina and Roland were called chlorofluorocarbons,

2:38 Speaker 1: usually shortened to CFCs. These compounds had become extremely popular

2:44 Speaker 1: during the mid twentieth century because they were considered miracle chemicals.

2:48 Speaker 1: They were stable, non flammable, non toxic at ground level,

2:53 Speaker 1: and chemically inert in most everyday situations. Because of those properties,

2:58 Speaker 1: they were used everywhere refrigerators, air conditioners, foam packaging, and

3:04 Speaker 1: especially aerosol spray cans. Millions of households used products containing

3:09 Speaker 1: CFCs every single day. In fact, if you lived in

3:13 Speaker 1: the nineteen seventies, there was a very good chance that

3:17 Speaker 1: every morning routine involved at least one quick blast of

3:20 Speaker 1: a CFC powered aerosol spray. Hair sprays were especially famous

3:25 Speaker 1: for this, and if you grew up in that era,

3:28 Speaker 1: you may remember a certain legendary brand whose aerosol clouds

3:31 Speaker 1: could practically withstand a hurricane. Yes, the towering helmet hairstyles

3:36 Speaker 1: of the late twentieth century were often held in place

3:39 Speaker 1: with heroic amounts of hairspray, and more than one scientist

3:43 Speaker 1: jokingly suggested that half the ozone layer might have been

3:46 Speaker 1: sacrificed in the name of perfect bangs. If one brand

3:51 Speaker 1: had to be nominated as the unofficial mascot of the

3:53 Speaker 1: aerosol age. Many people would quietly point toward AquaNet, the

3:59 Speaker 1: hair spray so powerful it could freeze a hair style

4:02 Speaker 1: in place for days and possibly alert passing satellites. The

4:07 Speaker 1: problem with CFCs was not what they did near the ground.

4:11 Speaker 1: The problem was what happened decades later after those chemicals

4:14 Speaker 1: slowly drifted upward through the atmosphere. Because CFC molecules were

4:19 Speaker 1: so stable, they could remain intact for years, sometimes even decades,

4:24 Speaker 1: as they gradually rose into the stratosphere. Once they reached

4:28 Speaker 1: those higher altitudes, however, intense ultraviolet radiation from the sun

4:33 Speaker 1: began to break the molecules apart. When that happened, the

4:37 Speaker 1: chlorine atoms inside the molecules were released, and chlorine, as

4:42 Speaker 1: it turns out, is extremely efficient at destroying ozone. A

4:46 Speaker 1: single chlorine atom can trigger a chemical chain reaction that

4:50 Speaker 1: breaks apart thousands of ozone molecules before the chlorine finally

4:55 Speaker 1: becomes neutralized. This meant that even relatively small amounts of

4:59 Speaker 1: cf sea pollution could have enormous effects on atmospheric chemistry

5:04 Speaker 1: over time. When Molina and Roland published their findings in

5:07 Speaker 1: nineteen seventy four. The reaction from the scientific community was mixed.

5:13 Speaker 1: Some researchers immediately recognized the seriousness of the problem, but

5:17 Speaker 1: others were skeptical. The atmosphere is vast, after all, and

5:22 Speaker 1: many people believed it was simply too large for human

5:25 Speaker 1: activity to influence on a global scale. Chemical companies were

5:29 Speaker 1: particularly critical of the research, arguing that the calculations were

5:33 Speaker 1: speculative and that the atmosphere's complexity made such predictions unreliable.

5:39 Speaker 1: Yet the scientists continued studying the problem, running more models

5:44 Speaker 1: and examining atmospheric data. Their calculations suggested that if CFC

5:50 Speaker 1: production continued to grow at the same rate, the ozone

5:53 Speaker 1: layer could thin dramatically over the coming decades. At first,

5:57 Speaker 1: the warning seemed theoretical. There was no visible hole in

6:01 Speaker 1: the sky and no obvious sign that anything was wrong.

6:05 Speaker 1: But as the years passed, atmospheric measurements began to reveal

6:08 Speaker 1: subtle changes in the chemistry of the stratosphere. Then, in

6:13 Speaker 1: the mid nineteen eighties, scientists studying Antarctica made a shocking discovery.

6:19 Speaker 1: Each spring, ozone levels above the continent were collapsing dramatically,

6:24 Speaker 1: creating what became known as the Antarctic ozone hole. Satellite

6:29 Speaker 1: observations confirmed the phenomenon and showed that the thinning was

6:33 Speaker 1: far more severe than scientists had predicted. The invisible chemical

6:37 Speaker 1: process Molina and Rowland had warned about was actually happening.

6:41 Speaker 1: The discovery triggered a rare moment of global cooperation. Governments

6:45 Speaker 1: around the world realized that the problem required a coordinated

6:49 Speaker 1: international response. In nineteen eighty seven, dozens of nations signed

6:54 Speaker 1: the Montreal Protocol, an agreement designed to phase out the

6:57 Speaker 1: production of CFC's and other ozone depleting substances. The treaty

7:02 Speaker 1: forced industries to develop alternative chemicals and dramatically reduced the

7:07 Speaker 1: global use of the compounds responsible for the damage. Remarkably,

7:11 Speaker 1: the agreement worked over the following decades. Measurements showed that

7:16 Speaker 1: ozone depletion began slowing and that the atmosphere was gradually

7:20 Speaker 1: beginning to heal. The entire episode remains one of the

7:23 Speaker 1: strangest environmental stories in history. Humanity accidentally damaged the protective

7:30 Speaker 1: chemistry of the planet simply by inventing useful household products.

7:34 Speaker 1: A combination of refrigerators, industrial processes, and an impressive amount

7:39 Speaker 1: of hair spray had quietly altered the atmosphere itself. Yet

7:44 Speaker 1: the story also contains an unusual note of optimism. Once

7:49 Speaker 1: scientists understood the problem, governments and industries actually worked together

7:54 Speaker 1: to solve it. Today, researchers believe the ozone layer is

7:58 Speaker 1: slowly recovering, though the process will take many decades to complete.

8:04 Speaker 1: In nineteen ninety five, the importance of the discovery was

8:07 Speaker 1: formally recognized when Mario Molina, F. Sherwood Rowland and atmospheric

8:13 Speaker 1: chemist Paul Krutson received the Nobel Prize in Chemistry for

8:17 Speaker 1: their work explaining how human activity could alter the atmosphere.

8:22 Speaker 1: Their research revealed something both alarming and hopeful at the

8:25 Speaker 1: same time. Humanity had the power to change the chemistry

8:29 Speaker 1: of the sky itself, but it also had the ability

8:32 Speaker 1: to recognize the problem and correct it. A brief word

8:36 Speaker 1: from our sponsor.

8:38 Speaker 2: This episode is brought to you by nineteen eighties hair technology.

8:42 Speaker 2: Do you want a hairstyle that can survive rainstorms, high winds,

8:45 Speaker 2: and possibly low orbit Try our revolutionary industrial strength aerosol hairspray.

8:52 Speaker 2: One quick blast and your hair will remain perfectly frozen

8:55 Speaker 2: in place until the next geological epic. Scientists say the

8:59 Speaker 2: ozone layer they recover slowly over the next few decades,

9:02 Speaker 2: but your bangs will remain absolutely unchanged. Nineteen eighties hair

9:07 Speaker 2: technology because nothing says style quite like a hairstyle that

9:11 Speaker 2: can deflect small asteroids.

9:14 Speaker 1: Dear listeners, March twentieth reminds us that history is not

9:17 Speaker 1: always shaped by dramatic events we can see unfolding before

9:21 Speaker 1: our eyes. Sometimes it is shaped by invisible chemistry happening

9:25 Speaker 1: miles above our heads, discovered by scientists asking questions that

9:30 Speaker 1: most people never thought to ask. And occasionally it is

9:34 Speaker 1: shaped by something as ordinary as the contents of a

9:36 Speaker 1: spray can sitting quietly on a bathroom shelf. Until next time,

9:41 Speaker 1: stay curious and maybe go easy on the hairspray.

10:02 Speaker 2: B b

10:27 Speaker 1: B eight