NOVA travels to Antarctica with an emergency scientific expedition to study a baffling "hole" in the Earth's protective ozone layer.
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00:00Tonight on NOVA, Antarctica, a mysterious hole in the ozone layer over this frozen continent
00:15has summoned an emergency expedition here to uncover its cause.
00:19The actual size of it, you could compare it to the thickness of Mount Everest, the size
00:26of the United States.
00:28Is it a signal that something is dreadfully wrong with the global ozone layer?
00:33Join us tonight as the mystery unfolds, The Hole in the Sky.
00:43Major funding for NOVA is provided by this station and other public television stations
00:47nationwide.
00:51Additional funding was provided by the Johnson & Johnson family of companies, supplying health
00:55care products worldwide.
00:59And by Allied Signal, a technology leader in aerospace, electronics, automotive products
01:05and engineered materials.
01:25Looking up from Earth, the sky appears boundless, a celestial canopy of peace and beauty unmarked
01:37by human imprint.
01:41Viewed from space, the global atmosphere is eggshell thin, a delicate blue haze encircling
01:47the Earth.
01:49It is the domain of wind, clouds, the air we breathe, the roof of our world.
01:57Antarctica, the coldest place on Earth.
02:03Here a mysterious change has been detected in a vital element of the atmosphere, a piece
02:08of the sky has vanished.
02:11This may be an isolated event confined to this remote continent, or it may be nature's
02:16first warning that man is changing the global atmosphere in ways that will profoundly affect
02:21all life on Earth.
02:27What is at risk is a form of oxygen called ozone, which makes up a fraction of a millionth
02:32of the planet's atmosphere.
02:34This invisible layer, 15 miles high, acts as a sunscreen around the Earth, our only
02:40protection from deadly ultraviolet rays.
02:44All life, save that in the deep oceans, has evolved under it.
02:50Scientists warn that ozone depletion would affect every nation on the globe, with major
02:55effects on human health, including higher incidence of skin cancer, cataracts, and depression
03:00of the immune system.
03:04Losses of ozone would affect climate, damage the growth of plants, and disturb the food
03:08chain.
03:11The hole in Antarctica's sky may be the first signal of a threat to the entire world.
03:19Bob Watson directs NASA's program of upper atmospheric research.
03:23He is at the center of an international debate about how to protect the ozone layer.
03:28We can't change the rate at which ozone is produced, but we can change the rate at which
03:32ozone is destroyed.
03:33And so what we're worried is that we're slowly reducing the level of ozone constantly.
03:38In the past decade, scientists have come to realize the Earth's atmosphere is changing
03:42rapidly.
03:43For the first time, waste from industrial activity may be altering climate on a global
03:49scale.
03:53By the end of the century, an unnatural shift called the greenhouse effect is predicted
03:57to make the Earth warmer than it has been in the past 100,000 years.
04:03The same man-made gases involved in greenhouse warming also affect ozone.
04:09Climate fluctuates naturally on a grand scale, so it is difficult to separate out changes
04:14which may be human-induced.
04:17Antarctica's ozone hole provides a natural laboratory for studying a dramatic change
04:22which may or may not be of human origin.
04:26Only since the early 70s has man been able to look at Earth from a global perspective,
04:31with satellites in space and high-speed computers on the ground.
04:36But neither a satellite nor a computer detected the Antarctic hole.
04:41It was first noticed by a little-known British research group led by Joe Farman.
04:46We have been measuring ozone in Antarctica since 1957, and these are, in fact, the longest
04:51series in the southern hemisphere.
04:53We were, I suppose, like everyone else, looking for long-term trends which were going to be
04:57quite difficult to find.
04:59And then suddenly, before our eyes, we seemed to see something completely different, a seasonal
05:03variation of depletion.
05:06And this was so unexpected that we really felt we had to make quite certain our instruments
05:11were in good order and the calibrations were correct before we could announce this to the
05:15world.
05:17Farman's data revealed that October levels of ozone over Antarctica had dropped 50 percent
05:22in less than a decade.
05:26His measurements came from a simple ground-based instrument.
05:29If you have your hands on the data, and if you're actually writing things down, you almost
05:33have a tactile way of acquiring information.
05:36You get a feel for it.
05:37There's an experience alone can do.
05:40He found it strange that no one else had reported the ozone hole, and at first doubted his own
05:45findings.
05:46At the same time, we knew there were satellites flying over the world which should be seeing
05:50this, and it was very important not to set them off on a red herring if, in fact, we
05:55were wrong.
05:56So we had to go back, we had to check all the old observations with the instrument and
05:59make quite sure there were no calibration errors.
06:03Farman's findings opened an international investigation into one of the most puzzling
06:07mysteries ever to confront atmospheric science.
06:12But if Farman was right, why hadn't the global satellites seen the ozone hole?
06:18At the Goddard branch of NASA, scientists read the report and searched for evidence
06:22of the hole in the past six years of satellite data.
06:26Richard Stolarski.
06:29When the British first reported the ozone hole over Halley Bay, we went back and looked
06:34at our satellite data, which comes in at the rate of nearly 200,000 data points per day.
06:42To me, the data is sometimes overwhelming.
06:45When the instrument was first designed in the 1970s, it was thought that ozone values
06:52as low as are now being seen over the Antarctic would not occur.
06:57And thus, the computers which take this data and turn it into ozone values were programmed
07:07to simply drop values that low, assuming that they were in error.
07:12NASA had programmed its computers to ignore what was most interesting.
07:17When they sifted through the past seven years of Antarctica's October data, they found the
07:21hole.
07:23Shown here at the center of this projection, it is the size of the United States.
07:29We could confirm their results and we could extend the picture so that we could see the
07:33entire Antarctic region.
07:35That allowed us to see that it was not just a phenomenon of Halley Bay, but that it was
07:41a phenomenon of the entire region and it moved around and was not static.
07:47During part of October, the hole hovers over the American Research Station at McMurdo Bay.
07:52If you zoom in on McMurdo there, it looks like it's right on the wall of the hole again.
08:01The real issue here, I believe, is whether or not this is an isolated phenomenon specific
08:08to the region of the Antarctic or whether it is some indication of a miscalculation
08:15on our part as to what models are saying about the globe.
08:19Science has come to depend upon computer models to understand the atmosphere and its driving
08:24forces.
08:25The rotation of the earth, clouds, wind, temperature, precipitation, and the mighty engine of it
08:32all, the sun.
08:35The atmosphere is a complex chemical factory.
08:38Astronomers must simulate 200 known reactions, about 40 of which strongly affect ozone.
08:45The sun's ultraviolet light constantly creates and destroys ozone, which is a highly unstable
08:50gas.
08:53When molecular oxygen is struck by ultraviolet rays, its chemical bond is broken, releasing
08:59two highly reactive oxygen atoms.
09:02Each of these atoms joins with molecular oxygen, forming ozone, or O3.
09:08Ultraviolet light goes on to destroy its creation, striking ozone again.
09:13More molecular oxygen is formed, along with renegade single atoms of oxygen, which search
09:18for more molecules to destroy, including ozone.
09:24This pattern repeats over and over during the daytime, so ozone and oxygen are continuously
09:29created and destroyed.
09:32The relative amount of each substance remains the same, held in a delicate balance.
09:38This is how ozone works in most locations, but over Antarctica, the atmosphere is unique.
09:46Throughout the winter, which comes in July, August, and September, a high rotating mass
09:50called the polar vortex captures air in a kind of swirling chemical cauldron.
09:56The air inside this funnel gets cut off from replenishing global air currents.
10:01There is little sunlight during the long polar winter to generate new ozone, so the
10:05level remains the same.
10:09A month after the sun's return in Antarctic spring, the vortex collapses, allowing normal
10:14circulation to resume.
10:22In the last 10 years, the amount of ozone in the vortex has dropped a dramatic 50% below
10:27previous levels.
10:30No one knows why, but theories abound.
10:35Since the original paper appeared in Nature, we've really had a very good time, because
10:38we've had so little data to check ideas against, so everyone has taken the opportunity to wave
10:43their hands and produce all their pet ideas out of the cupboard and see if they can possibly
10:48be used towards this problem.
10:51There are two sets of ideas, those that attribute the hole in the sky to natural phenomena and
10:56those that blame it on man-made chemicals.
10:59One natural explanation invokes wind dynamics, pushing ozone up through the vortex in a kind
11:04of fountain effect.
11:07Another natural theory blames volcanic dust particles from the eruption of Mexico's El
11:11Chichon in 1983.
11:14Drifting south to the pole, these particles may provide a surface for chemical destruction
11:18of ozone.
11:21A solar theory suggests that a chain of natural chemical reactions triggered by abnormally
11:26strong solar flares may be destroying ozone.
11:32This same theory cites strange nitrogen gases produced during auroras, disturbances of the
11:37Earth's magnetic field, which are common in Antarctica.
11:43The leading suspect on the man-made side is a class of chemicals called chlorofluorocarbons,
11:48or CFCs, known to destroy ozone in the laboratory.
11:53CFCs are used as solvents for cleaning computer chips, refrigerants for car and building air
11:59conditioners, both as coolants and insulation for refrigerators, and as blowing agents used
12:05to make styrofoam egg cartons and fast food packaging.
12:10Outside the U.S., CFCs are used as aerosol propellants for anything from foot spray to
12:15hairspray.
12:18The CFC debate began in 1974, when Sherwood Rowland and Mario Molina of the University
12:24of California, Irvine calculated that chlorine in CFC chemicals posed a threat to the ozone
12:30layer all over the world.
12:32CFCs can last for a century in the atmosphere.
12:36Once they drift up into the stratosphere, they are bombarded with ultraviolet light,
12:40torn apart, and chlorine is released.
12:45This chlorine atom steals oxygen from the ozone molecule, beginning its cycle of destruction
12:49by forming chlorine monoxide, or CLO.
12:54The sun also strikes ozone, leaving free oxygen, which collides with CLO, releasing molecular
13:00oxygen and free chlorine.
13:04This process may repeat up to 100,000 times for every atom of chlorine.
13:11The groundwork for this understanding was laid by chemist Sherwood Rowland, who pointed
13:15out that CFCs do not break down in the lower atmosphere, but survive to destroy ozone in
13:21the stratosphere.
13:23He has since become an activist for CFC regulation.
13:27For a long time, the view was that if you put something into the atmosphere, it went
13:32away.
13:33And what we have found now is that it doesn't go away, it accumulates there.
13:38And it's accumulating very rapidly.
13:39And it's made it a very large-scale, global experiment, an experiment whose end we don't
13:46see, and one experiment which we probably ought to be ending as quickly as possible,
13:51get back to leaving the atmosphere alone.
13:55A different analysis of the problem comes from DuPont, a major producer of CFCs.
14:01I am very comfortable that based on our projections of the effect on the ozone layer of current
14:08levels of chlorofluorocarbons emissions, and modest growth in those levels, does not
14:14represent a threat to the health of our human race on out 50 to 100 years from now.
14:22The one thing which the lack of comprehension of the Antarctic ozone hole shows is indeed
14:28we understand very little about the atmosphere.
14:30We often congratulate ourselves on understanding a lot of it, but in fact we're really very
14:34ignorant.
14:36The theory behind ozone destruction is well established, but is the global ozone layer
14:40in fact being depleted?
14:42Are CFCs indeed to blame?
14:45Perhaps the Antarctic hole will provide some hard evidence.
14:49In that hope, an emergency national ozone expedition is launched in August of 1986.
14:55Four teams of scientists undertake a hazardous midwinter journey to McMurdo Bay.
15:02Halfway from New Zealand, the plane's wing ices up and the pilot is forced to turn back.
15:07The next day, they make it.
15:13It has taken 15 hours to clear the blowing snow off the runway.
15:18The plane must drop off its passengers and cargo and quickly take off again before it
15:22freezes.
15:23The temperature is 30 below.
15:28The expedition hopes to gather the hard data to answer questions both intriguing and urgent.
15:33Is the hole of man-made or natural origin?
15:37Is it the first signal that all is not well with the global ozone layer?
15:44Located on the edge of the Ross Ice Shelf, McMurdo Station has a winter population of
15:48100 people.
15:50The four U.S. bases in Antarctica are coordinated by the National Science Foundation, which
15:55has joined with NASA, NOAA, and the Chemical Manufacturers Association to launch this expedition.
16:02Leading the team is Susan Solomon, a young atmospheric chemist from Boulder, Colorado.
16:08Just getting a field experiment to work in Antarctica is a real challenge.
16:12The other thing that's challenging about the whole problem is that it's a mystery which
16:16has suddenly emerged, which we didn't expect, and which has caused us to re-examine everything
16:23that we thought we understood about atmospheric chemistry.
16:26I find that extremely exciting and challenging.
16:29In the commanding darkness of late winter, Solomon uses moonlight to take the world's
16:33first polar measurements of chlorine and nitrogen compounds.
16:37These will help to prove or disprove the CFC and the solar theories.
16:47The team tries to capture the moon in a mirror and aim its light down a hole in the roof.
16:54The conditions on the roof were extremely cold on many occasions.
16:59Temperatures could be as cold as minus 40, wind speeds of the order of 40 miles an hour,
17:04so it was very hard work staying up there for 10 or 15 minutes making an observation.
17:08What are we doing, blue or red?
17:10This is a red, 22nd red.
17:13Good.
17:14Well, when we first got here in late August, we observed ozone levels which were actually
17:19rather high, even though we were in the middle of the vortex.
17:23About three weeks later, we came back into the vortex and the ozone had dropped through
17:28the floor.
17:29It was lower than 200 Dobson units.
17:32And that was, at the same time, very frightening and at the same time extremely interesting.
17:39The hole's rapid appearance suggests a chemical mechanism to Solomon, but she continues to
17:43gather evidence, now in October, using the light of the sun.
17:47Yeah, it looks good.
17:49Let's go ahead then.
17:50I guess we'll take a couple of blues, take three blues and then a couple of reds.
17:54Okay.
17:55Incoming light carries a distinct signature of the atmosphere's chemical composition,
18:00revealing which chemicals have been encountered on the journey from the sun.
18:04Each molecule takes a characteristic bite out of the wavelengths of blue and red.
18:09Oh, real good, 52,000 pounds.
18:12Alright.
18:13If the vortex stays over McMurdo long enough, the expedition may be able to gather enough
18:18data to piece together this atmospheric puzzle.
18:22A team from the Stony Brook branch of the State University of New York searches for
18:26chlorine monoxide.
18:28Since there are few natural sources of chlorine, high levels of this molecule would strongly
18:32suggest that man-made CFCs are causing the hole.
18:36Bob DeZafra and Phil Solomon, no relation to Susan, use a microwave instrument they
18:41built themselves.
18:42Phil thinks the ozone hole may remain unique to Antarctica.
18:47Conditions in Antarctica are very peculiar in at least three ways.
18:51The air mass in the stratosphere over Antarctica is isolated for many months, it's dark for
18:57many months, and it's very much colder than any other place except the Arctic.
19:03The coldness probably produces clouds at altitudes where they're not produced in other parts
19:08of the world.
19:09All of these three phenomenon, combined with the fact that the ozone depletion is really
19:14only a springtime phenomenon and that there is a complete recovery, suggests to me at
19:18least that it may be a special problem to Antarctica.
19:22DeZafra and Solomon hope the chlorine monoxide measurement will deliver the definitive evidence
19:26on the controversial issue of CFC involvement.
19:32A University of Wyoming team launches a balloon-borne instrument to take the first direct measurements
19:37of ozone at various altitudes inside the hole.
19:40David Hoffman.
19:42Flying balloons in Antarctica in winter is something we've never done before, and the
19:47temperature extremes, minus 40, minus 50 degrees, are very severe on both the balloon and the
19:54people launching it.
19:55The winds can be very high, which makes ballooning very difficult.
19:58So it was a real challenge to find out if we could get these balloons off.
20:04And also in the stratosphere, the temperatures are even colder, like minus 120 degrees Fahrenheit,
20:09and we had no idea if the fabrics in the balloons would be able to withstand these temperatures.
20:14The first two months went very rapidly.
20:17We were very anxious to get to work, and we did a lot of work.
20:20We were never bored at any time.
20:22And I really enjoyed it as compared to the summer period down here when there's so many
20:27people.
20:28It was much easier working with fewer people.
20:31Liftoff is scheduled for 6 a.m.
20:33It's always a tense time just before the launch.
20:38The winds must be strong enough and traveling in the right direction so the balloon won't
20:42crash into buildings or telephone wires in town.
20:51Hey, beautiful.
20:57Great, looks good.
20:59The balloon detector will also count ice and dust particles, providing clues as to whether
21:03the volcanic or the wind dynamic theories may be correct.
21:07If the dynamic idea holds merit, Hoffman should see particles rising up through the hole in
21:12the fountain effect.
21:14When people talk about an ozone hole, you would think of a hole bored down into the
21:19atmosphere, perhaps, where there's no ozone.
21:22And what we find is that it's not that at all.
21:24It's more like the shape of a wafer.
21:27And the actual size of it, you could compare to the thickness of Mount Everest, the size
21:34of the United States.
21:36Hoffman uses telemetry to track the balloon, which sends electronic signals to receivers
21:41inside this dome.
21:44It's out of sight.
21:45It must be in the clouds.
21:49This is right at the base of the ozone hole.
21:51We're just getting into the region now where the ozone depletion has occurred.
21:56Internal temperature in the ozone package is 24 degrees, so it's nice and warm in there.
22:01The ozone pressure is now up to 50 nanobars, but these are very low values.
22:06And it's roughly half of what it would be at about 50,000 feet.
22:12While the Wyoming team samples ozone directly inside the hole, a team from the Jet Propulsion
22:17Laboratory in Pasadena, California, takes measurements from the ground.
22:22This remote hut was built especially for their $3 million instrument.
22:28Barney Farmer heads the research team running the infrared spectrometer, a version of which
22:32has flown on the space shuttle.
22:35Peering through a window directly at the sun, this instrument uses a laser to take precise
22:39readings of more than 30 different chemical molecules in the atmosphere.
22:43I can't tell yet, but the sun's not quite bright enough.
22:46What time does it rise today?
22:48Let's see. I think it's just after 3 o'clock, about 310.
22:52It gets earlier every day.
22:54I know. Less and less sleep, more and more work.
22:57I'm going to put heat on just for a few minutes, OK?
23:00All right.
23:04The sun emits radiation over a wide range of wavelengths.
23:08We're concerned with the infrared part, which is the region of wavelengths just longer than
23:13visible radiation.
23:14As the radiation is transmitted towards the surface of the earth, the atmospheric molecules
23:20absorb, remove rather specific frequencies.
23:24Each molecule removes its own radiation.
23:28And so we end up with a signature of the atmospheric composition.
23:34And this is rather like fingerprinting the atmosphere, so we have a simultaneous measurement
23:38of the whole infantry of species.
23:41Because of the sophistication of their instrument, Farmer's team won't be able to look at their
23:45data until they get back to the computers in California.
23:49But ultimately, their work will provide the most comprehensive picture of chemical elements
23:53inside the ozone hole.
23:58New information on the position of the hole carries disappointing news for the Stony Brook
24:02team. Bob DeSafra.
24:04I think the biggest surprise to everyone when we arrived here and began to see Dave Hoffman's
24:10balloon experiment results is that the ozone depletion is occurring in a lower level in
24:15the stratosphere than had been anticipated.
24:18That's particularly frustrating to our experiment because we're primarily sensitive to chlorine
24:25monoxide emission from the middle stratosphere.
24:29And what's happening is that if there is chlorine monoxide, it's going to be in the lower
24:33stratosphere. That poses a real problem for us to try to get the sensitivity needed to
24:39extract some information about that low layer of possible chlorine monoxide.
24:46And so the ozone hole does not give up its secrets quite so easily. The Stony Brook team
24:51has cheated of its prize, measuring the kingpin chlorine monoxide molecule inside the hole.
24:57Just in the context of this...
24:59Once a week, the four teams gather to put their findings together. Tonight, they try
25:03to fit what they are learning day by day into existing computer models.
25:07The problem that we're facing is that nobody has built a model that simulates these observations.
25:14For one thing, nobody knew about these observations until a couple days ago.
25:19Within the group, there are strong disagreements over interpretation of data.
25:24I don't think you can evaluate your data by comparing it against a model unless you really
25:29knew that the model would produce this.
25:31If we take what we heard from Dave just before, if it's 18 kilometers, 60 millibars, right
25:37now or in late September, that's fine.
25:40But even at 18 kilometers, Phil, the depletion is dying out.
25:44It's not dying out. He showed it. That's not what he showed at all, Susan.
25:48Emotions run high, partly because of the expectation that these scientists will come up with a
25:52definitive answer on the cause of the hole.
25:57Well, particularly when you're dealing with something as controversial as the ozone hole,
26:01the problem is that it can never be a purely objective judgment.
26:06So, of course we've had disagreements, but I think those have been healthy.
26:09They've caused us all to think.
26:12It soon becomes clear that another year of observations will be needed.
26:16Still, the expedition has learned enough to cast doubt on two key theories.
26:20As Susan's experiment showed, nitrogen dioxide levels are very low, ruling out solar activity.
26:26Dave's balloon found no evidence of particle uplifting.
26:29The fountain effect is not in sight, although other dynamic mechanisms cannot be ruled out.
26:35The altitude of the hole is between 12 and 20 kilometers, much lower than previously thought.
26:40The rapid appearance of the hole with the springtime sun suggests a photochemical process.
26:45Whether natural or man-made has yet to be determined.
26:48And what about chlorine from CFCs?
26:51It could very well be that the ozone hole is caused by something completely different from what's been proposed so far.
26:57But based on the existing theories, chlorine is the only one we can't rule out.
27:01Until we've analyzed all the data, it's going to be very difficult to make any statement about chlorine.
27:08Scientific caution sometimes conflicts with personal conviction.
27:11When is the evidence strong enough to take action?
27:15Given the stakes, Barney Farmer believes we have reached that point.
27:19There's no question in my mind that we have a problem.
27:21Since the days over ten years ago now, when we first measured hydrochloric acid in the atmosphere,
27:27in an amount that was almost exactly what you would expect from the destruction of the CFCs that we'd used up to that time,
27:35and then the hydrofluoric acid, and hydrofluoric acid, HF, has only man-made chemicals as its source.
27:43We've watched both of those species, those molecules, grow in the upper atmosphere to the point where they are today.
27:52It doesn't take a scientist to point out that we're doing something that we shouldn't be doing to the atmosphere,
27:57and that we'd better stop it if we don't want a real problem.
28:01Even if the hole remains confined to Antarctica, the region will be a test case of how ozone changes affect life.
28:08Many creatures live underwater, protected from ultraviolet rays.
28:12Birds may gain some protection from their feathers,
28:15but scientists have not yet begun to study what biological effects may happen here.
28:21We don't understand the cause of the depletion of the ozone layer.
28:24If a change like that were to pop up somewhere else, it would be extremely damaging to biological life.
28:31If it's happening here and we don't understand the causes of it, how can we be sure that it won't happen somewhere else?
28:37So it's imperative that we do the most we can to uncover the cause,
28:42so that we can understand whether it is something which is going to be restricted to Antarctica for the rest of eternity,
28:48or whether it has some real implications for other parts of the world.
28:53Joining a three-month mission to Antarctica requires a certain kind of spirit, and more than a few sacrifices.
29:01I had to give up Monday night football.
29:07We don't have any bathtubs in McMurdo, it's all showers.
29:23I rather enjoyed it here. I may get in trouble when I get home saying that, but...
29:38All right.
29:44Meanwhile, back home in Washington, the press was poised and waiting for the latest news from McMurdo.
29:51McMurdo, McMurdo, this is NSF Washington, this is NSF Washington, do you read me, over?
30:01Excuse me, this is the DROM operator, would you please speak closer to your microphone in Antarctica?
30:06I can't get much closer than I am. Can you hear me at all?
30:11Roger, David, we're getting you loud and clear now.
30:14The transmission was at times a little murky, and so was the message.
30:18The press corps looked puzzled, probably with good reason.
30:22Could you tell us what your experiments have told you?
30:25Do you think that these chlorofluorocarbons are causing this depletion and the ozone hole that you are studying?
30:31As I just said, we do not feel that we have established the cause of the hole at this time.
30:37However, we believe that a chemical mechanism is fundamentally responsible for the formation of the hole.
30:42Dr. Sullivan or anyone else who's there, many of us will be broadcasting to Americans all over America from the 8th grade on up.
30:50Could you possibly think in terms of instructing an 8th grader and describe your strong evidence against the proposed
30:57dynamical and solar models of the hole formation and define the dynamical and solar models? Simply.
31:05Okay, uh, how do you want that edited?
31:09Music
31:25Some new ideas held more promise than others.
31:28While the expedition took observations at McMurdo, Jerry Malmon of Princeton University was working up a new dynamics theory based on his computer model.
31:37Modeling the atmosphere is an extremely difficult thing.
31:40Effectively, what we're trying to do is stuff the entire atmosphere into a computer.
31:44You think about it, that's really quite preposterous that anyone would even try it.
31:48But what's amazing is that we've had stunning successes, but we have a long, long ways to go.
31:53It's a hard, hard problem.
31:56Which brings us to the story of the Chinese lunch.
32:00Well, last spring I was at a scientific meeting on the Antarctic ozone hole.
32:05And a few of my chemical colleagues and I were arguing on chemistry versus dynamics.
32:10So just for fun, I offered them a bet that the ozone hole would actually get less deep this year.
32:16And two of my prominent takers were Susan Solomon and Bob Watson.
32:21And it looks like I've won the bet.
32:25Latest NASA measurements reveal that both temperatures and ozone levels were up slightly in 1986.
32:31Malmon claims this supports his theory for how dynamics may be contributing to the Antarctic hole.
32:38Malmon's model holds that under normal conditions, atmospheric waves carry ozone and heat from the tropics to the South Pole.
32:47If for some reason these waves dropped off and temperatures fell, less ozone would reach the pole.
32:53Still, there is no explanation for why this may have happened or the speed with which the hole appeared.
33:00Malmon himself admits his theory may require a chemical mechanism as well.
33:06In my opinion, it's very common that unusual or singular events are often the result of a combination of improbable events.
33:16Every car accident you were ever in probably is in that category.
33:20Every hurricane, every severe storm, every hailstorm, every thunderstorm requires a confluence or superposition of unusual and somewhat rare events that add up to make a very impressive phenomenon.
33:35We scientists have spent a lot of time arguing with each other, is it chemistry or is it dynamics, and if so, what?
33:42And my suspicion is that after the smoke clears, that we will find that it indeed was a combination of chemistry and dynamics that really explain Antarctic ozone as it happened.
33:58And what do computer models say about global ozone? If they fail to predict the Antarctic hole, can they still be trusted?
34:06It's a good question to find out whether we believe in the models.
34:08We test them normally against the measurements of the normal atmosphere at mid-latitudes, and there they do a reasonably good job.
34:14They clearly have not done a very good job in the Antarctic region.
34:17However, that region may be very, very unique.
34:20We know it's dynamically unique and it's got very unique radiation properties.
34:24And so just because we failed miserably to understand Antarctic ozone doesn't necessarily mean to say that our understanding of the global ozone problem is equally as bad.
34:33As perplexing as the Antarctic ozone hole is, the real fear is that it may be the beginning of ozone depletion all over the globe.
34:41The satellite has detected a smaller hole over Spitsbergen, Norway, near the Arctic Circle.
34:46There are also ground-based indications of possible depletions above Switzerland.
34:51These may be natural fluctuations, but they must be closely watched.
34:56At NASA, Donald Heath.
34:59The satellite instruments now are telling us that the global levels of ozone are decreasing.
35:04These measurements only cover a six-year period, so they really should only be taken as a warning.
35:10This is not a final conclusive evidence that man's activities are indeed destroying the ozone.
35:17But it tells us that ozone is decreasing, and we may have a very serious problem in the future.
35:24Over the past six years, an instrument aboard the Nimbus 7 satellite has shown a drop of 3% in the total amount of global ozone.
35:32But satellite instruments cannot be recalibrated in space and do drift in sensitivity.
35:38Scientists believe they have corrected for this drift.
35:41However, they are not entirely sure.
35:43NASA is now assessing the validity of its findings.
35:46At this moment in time, there is no reason to believe the satellite data has been incorrectly interpreted.
35:52However, it is such a new finding with such importance that we just have to be especially careful.
35:57The problem with finding a trend in global ozone is that ozone is not a steady quantity.
36:03If you look at the ozone, particularly over any point, you see that it fluctuates on all time scales.
36:09So the ozone level may be going up and down daily, weekly, monthly, yearly, and in fact may have cycles of a number of years involved in it.
36:20So that picking out the trend is trying to see a very small slope in something that's actually going this way.
36:28Definitive answers about global ozone depletion will require many more years of observation.
36:34The stakes are high, but so is uncertainty.
36:37The stage is set for a policy debate at the World Resources Institute, Rafe Pomerantz.
36:43When you talk about uncertainty, it seems as though we know nothing.
36:47Actually, if you listen, there are many, many things that people are very confident about.
36:51We do know that chlorine will destroy ozone in the stratosphere.
36:55We know that more carbon dioxide or chlorofluorocarbons or nitrous oxide in the atmosphere will warm up the Earth.
37:03We don't know quite how much or how fast, but we know it will occur.
37:07We also know that the levels of these changes going on in the atmosphere are very, very large.
37:15What would life be like in an ozone-depleted world?
37:20If the ozone shield were seriously damaged, intense doses of the sun's deadly ultraviolet radiation could bring major increases in the rate of skin cancer.
37:29Dr. Darrell Regal.
37:31In terms of skin cancer, there are certain things we can do to cut down our risk of developing this disease.
37:37We can wear sunscreens, which will protect us from the ultraviolet light that hits our skin.
37:42We can avoid the midday sun, which will protect us from the sun's strongest rays.
37:47And we can wear clothes that cover our skin, again, to protect ourselves from damage.
37:52However, once the ozone layer is depleted, there's really not much more we can do to protect ourselves from the increased ultraviolet light that's going to be hitting the entire world, and the problem of skin cancer is going to increase.
38:06For every 1% decrease in ozone, there's a 2% increase in the amount of damaging UV light reaching us.
38:14Depletion in ozone may also have implications for global food production.
38:20In an attempt to simulate an ozone depletion, Alan Teramura of the University of Maryland is blasting this soybean crop with artificially enhanced ultraviolet light.
38:31Overall, plants are affected by ultraviolet light in terms of a reduction in the growth of the plant, and that includes a reduction in leaf area, or the size of the leaf, as well as a general stunting or reduction in height of the plant.
38:47In addition, we know that ultraviolet radiation can affect the yield that's produced by the plant, as well as the seed quality.
38:56In one of our soybean varieties, Essex soybean, we found that a 25% ozone depletion results in between a 20% to 25% decrease in seed yield.
39:08Large increases in ultraviolet light would also affect the ability of ocean plankton to reproduce.
39:14Since plankton anchor the sea's food chain, this could cause disruptions which would propagate up the chain.
39:20New studies show that higher levels of ultraviolet light increase hydrogen peroxide, a key ingredient in the formation of acid rain.
39:29The connection may stretch ordinary bounds of belief, but a trip to the beauty salon in Paris may contribute to Waldsturm, or forest death in West Germany.
39:39In a curious twist, ultraviolet light combines with car exhaust to create ozone smog, which causes major damage to crops, over $2 billion in the U.S. alone.
39:50Too much ozone on the ground, not enough up there.
39:55Maybe what the world needs is an ozone rezoning act.
40:01Unfortunately, it's impossible.
40:03Ozone plays a vital role in regulating heat in the stratosphere.
40:07Once it is disturbed, climate may change in ways science cannot yet predict.
40:13Better understood is the greenhouse effect, climate change on a grand scale.
40:18The same gases which affect ozone also accelerate this global warming.
40:23At the Goddard Institute for Space Studies, Jim Hansen's model predicts dramatic increases in temperature.
40:29People often think that the greenhouse effect is something that will only affect our great-grandchildren, but actually it's a lot closer than you think.
40:37We expect that the temperature will have increased to a level which hasn't been experienced in 100,000 years within the next 10 to 15 years.
40:45And by the time we get to year 2030, which is 43 years from now, the temperature will be 4 to 6 degrees.
40:52And by the time we get to year 2030, which is 43 years from now, the temperature will be 4 to 7 degrees Fahrenheit warmer than it is now.
41:02If greenhouse gases continue to increase, the world may warm 2 degrees by the year 2000, 3 degrees by 2010, and up to 7 degrees by 2030.
41:14In further predictions for the middle of the century, Denver may go from its current 33 days a year over 90 degrees to 86 days.
41:23Washington may jump from 1 month to nearly 3 months.
41:27Dallas may leap from 3 months over 90 to nearly half the year.
41:31Carbon dioxide from the burning of fossil fuels, nitrous oxide from automobiles, emissions from CFCs, and methane from farming all contribute to the greenhouse effect.
41:43These gases act as a thermal blanket around the Earth, trapping solar infrared radiation reflected from the surface.
41:51CFCs contribute 20% to greenhouse warming, second only to carbon dioxide.
41:57Michael Oppenheimer is an atmospheric scientist with the Environmental Defense Fund. He warns of major ecological shifts in the making.
42:06The greenhouse effect will bring about the largest climate change in the experience of humankind, and it will happen in a quicker time scale than any other change in climate.
42:17We have no idea really what this will be due to the biosphere, but we can guess.
42:22Plants, animals are used to responding to climate changes that happen over the course of hundreds or maybe thousands of years.
42:28This change will happen in the course of 50 or 100 years.
42:32Disruptions in agriculture and water shortages are predicted.
42:37With shifting rainfall patterns, the Midwest may return to the days of the Dust Bowl.
42:43Sea level is expected to rise 3 feet within the next century due to thermal expansion of the oceans.
42:50This may cause flooding of coastal cities and low-lying areas such as Bangladesh and Indonesia.
42:57There are long-range concerns about melting of the polar ice caps.
43:02Uncertainties are associated with all models, and exactly what will happen where remains in question.
43:09These dire predictions also leave out one factor, the human ability to change.
43:15The hole in Antarctica's sky, whether of natural or man-made origin, helped to bring a sober realization
43:22that man may be capable of causing dramatic changes in the natural conduct of the planet's atmosphere.
43:30Although conclusive proof is a long way off, a movement has begun even within the chlorofluorocarbon industry itself toward controlling these chemicals.
43:39Part of the reason is that CFC production is growing at 5% a year, and demand is on the rise.
43:45First invented in the 1930s, CFCs are safe, cheap, and efficient.
43:51The products they made possible became part of our vision of the good life.
44:13Southern cities like Miami were able to grow and flourish partly because of air conditioning.
44:21When it was discovered in the mid-70s that CFCs might be dangerous to ozone, the U.S. unilaterally banned their use in aerosols.
44:30Companies soon came out with new environmental formulas propelled by hydrocarbons.
44:36In the meantime, CFCs have quietly grown again to the peak levels of 1978.
44:43The U.S. accounts for about 30% of CFC emissions worldwide.
44:48Major producers are DuPont, Allied Signal, Penwalt, Kaiser Industries, and Raycon.
44:57Until recently, the CFC industry has opposed any new regulation.
45:03The industry point of view since 1974 has seemed to me that chlorofluorocarbons are like people.
45:12They should be considered innocent until proven guilty.
45:16And I don't think that that's the proper approach.
45:19What we really need to do is to protect the atmosphere and not the chlorofluorocarbon industry.
45:24Historically, there's been a marriage of convenience between the scientists' tendency to say,
45:31don't ask me for a conclusion until the last results are in,
45:35and industry's desire not to have to make changes in the way it operates.
45:38So, in the past, the industry has been using scientific uncertainty as an argument for delaying any regulatory action.
45:48But last fall, the relationship between uncertainty and industry's position on regulation shifted dramatically.
45:57To everyone's surprise, the Alliance for Responsible CFC Policy, an industry coalition group, changed its mind.
46:05At a September press conference, President Richard Barnett.
46:09Responsible policy dictates, given the scientific uncertainties,
46:15that the U.S. government work in cooperation with the world community
46:19to consider establishing a reasonable global limit on the future rate of growth of fully halogenated CFC production capacity.
46:28Barnett is vice president of York Air Conditioning.
46:31He argues that the industry can do a lot to conserve CFCs on a voluntary basis,
46:36through product leak testing and making sure that CFCs do not escape during the manufacturing process.
46:44At the end of a product's useful lifetime, CFCs could be recovered and recycled,
46:49instead of being emitted into the atmosphere.
46:53At present, there is no provision for such CFC recovery.
46:57In the fall of 1986, DuPont, too, changed its stance on regulation
47:02and called for an international limit on CFC growth.
47:06DuPont commands about half of the U.S. CFC market.
47:11The company had been at work developing alternatives,
47:14but in 1980, when the regulatory climate quieted down, it shelved its research.
47:21Existing alternatives are not only more costly,
47:23but in some cases flammable, corrosive, or carcinogenic.
47:28The company now estimates it would take five to ten years
47:31to complete toxicity testing on possible alternatives and to bring new products to market.
47:37Without the threat of regulation, however, DuPont frankly admits there is no incentive to take these steps.
47:45It may require regulation to bring about alternatives,
47:48or the threat of regulation.
47:51If we go back in history, you'll find that in the mid-seventies,
47:56when the chlorofluorocarbons ozone issue was first elevated
48:00and the threat of regulation to aerosol producers was announced,
48:06the aerosol producers moved away from chlorofluorocarbons
48:10long before the regulation was put in place.
48:13So a threat of regulation is a threat to the environment.
48:16So a threat of regulation may have the same effect at this time.
48:21Protection of the ozone layer is the legal responsibility of the Environmental Protection Agency.
48:28In May of 1986, David Doniger of the Natural Resources Defense Council
48:33took EPA to court to force it to move faster on the issue.
48:37Administrator Lee Thomas.
48:40Well, I don't think it took the lawsuit to get us there.
48:43I think the lawsuit, and we have a lot of lawsuits,
48:47certainly focused attention in the agency on time frames for making decisions.
48:54The agency, I believe, was moving in the same direction
48:58that the people who brought the lawsuit wanted us to move in.
49:01But I do think the lawsuit contributed to us making decisions very concretely
49:06about the time frame within which we were going to do that.
49:08EPA must decide by November 1987 if the risk to ozone warrants further CFC regulation.
49:16The U.S. can provide a leadership position today just as I think it did back in the late 70s.
49:22In 1978, we banned all aerosols with CFCs because of our concerns about ozone depletion.
49:28Today, we're going into an international negotiation
49:32proposing a very strong position on dealing with this issue of ozone depletion
49:38in the future. I think there's also the potential for us looking at what we can do domestically
49:43and what we can do with export and import controls to deal with the issue as well.
49:47Environmental groups argue that the U.S. could take unilateral action,
49:52perhaps by restricting the import of cars using CFC number 12 in their air conditioners
49:57or computer chips cleaned with CFC solvents.
50:00But U.S. industry is adamant that any regulation should be global.
50:05There is no way that we can solve a stratospheric problem
50:10by taking a unilateral action in the United States
50:14and have chlorofluorocarbons production and emissions continue to grow around the world.
50:19It all ends up in the same stratosphere.
50:22As a result, we have to approach the problem globally.
50:26Geneva in December 1986.
50:28The United Nations Environment Program convenes a negotiation
50:32on an international global ozone agreement.
50:35We are here today because we recognize that urgent action is necessary
50:40to prevent destruction of the atmosphere's protective ozone shield.
50:45The U.S. delegation proposes to freeze CFC production at current levels
50:50and to phase out certain CFCs within 10 years.
50:53The international agreement, which we hope to achieve
50:56in the negotiations beginning here this week,
50:59would serve in effect as an insurance policy
51:03to protect future generations from the damages that we see occurring to the ozone layer
51:09and from the resultant effects on human health and ecology.
51:13The U.S. position was greeted coolly by industry observers.
51:17John Mills of Imperial Chemical of England.
51:20There is no environmental case for limiting CFC emissions to present-day levels.
51:27We believe that production limits could be set at a level
51:31which allowed industry the time to develop the necessary alternatives
51:38and for those to be evaluated by the user industries.
51:41If an agreement is made, it will be decided by delegates from nations.
51:45The European Economic Community has been most conservative about taking any action.
51:50It has yet to ban the use of CFCs in aerosols.
51:54Japan has also been slow to move toward regulation.
51:57CFCs are used heavily in its automotive and computer industries.
52:01Climate will change.
52:04The only uncertainties are when and by how much.
52:08The type of protocol we agree will be a determinant in this equation.
52:13I'm optimistic for the first time in many years that we can reach an international agreement.
52:18Industries and governments seem to be taking a much more flexible approach this year
52:22than they did even one year ago, let alone two years ago.
52:25An informal consensus was reached at Geneva
52:29that production of certain CFCs should be frozen at current levels.
52:33But a binding international treaty may be years away.
52:37Meanwhile, science does not provide answers according to society's timetables.
52:42There is no final word yet on the cause of the Antarctic hole.
52:46Further analysis of the National Ozone Expedition's data may provide more clues as to the cause.
52:52A second expedition is planned for next season.
52:55With risks and uncertainties both so high,
52:58scientists have been unusually forthcoming about their personal views.
53:02Well, I think myself that we should look on the Antarctic ozone hole
53:07as nature's way of giving us a gentle warning
53:09on a rather restricted temporary stage.
53:12Until we know that this is some natural phenomenon,
53:15we should heed that warning and take some action
53:18to at least reduce the use of chlorine-containing chemicals.
53:22It's quite obvious that people will have to be licensed
53:26to put things into the sea or into the atmosphere in the future.
53:29It should be just like the pharmaceutical industry.
53:31It should be up to the releaser to prove that something is safe
53:34and not up to the scientists to prove that it is dangerous.
53:37Society certainly can't trust the models to provide a definitive answer
53:43which will enable them to quantitatively regulate the CFCs.
53:47But what I think is significant is the fact that the models were taken by surprise.
53:51The fact that we can fail to understand the ozone layer so completely
53:56that we've seen a 50% depletion that we don't understand
53:59has to be an indication that we need to consider very carefully
54:03what we're doing to this planet, in my opinion.
54:05There will always be something more to be learned
54:08by studying it for another three or four years.
54:10Primarily what we're learning now is that the ozone is going away
54:14and it's time to act on what we already know.
54:18This is an issue that affects not only us but our children.
54:22We should be concerned today.
54:24If we put large amounts of CFCs into the atmosphere,
54:27if they were to have an adverse effect on either the climate system
54:30or the ozone system, once we've recognized that concern,
54:32it would take decades to centuries for the system to recover.
54:36Therefore we can't simply say,
54:38let's put off decision-making for another decade or so
54:40insofar as if we do get a problem, that problem will last for centuries.
54:46Science cannot tell us for certain if or when the global ozone layer will be depleted.
54:52It has told us that CFCs remain for a century in the atmosphere,
54:56that they can destroy ozone,
54:58and that they make a substantial contribution to global warming.
55:02It is up to society to weigh these known risks,
55:06to search for a better understanding,
55:08and finally to decide if and when this global atmospheric experiment should cease.
55:32Transcription by ESO. Translation by —
56:02Transcription by ESO. Translation by —
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