
GLWAOOOK "What's Up With the Weather?"
Air date: April 11, 2000
A NOVA/FRONTLINE Special Report
What's Up With the Weather?
Written, produced and directed by Jon Palfreman
NARRATOR: From record heat to raging storms, something strange is
happening with the weather.
Vice Pres. AL GORE: Global warming is real.
NARRATOR: Or is it?
FRED PALMER, Western Fuels Association, Inc.: There is no basis to say
that more CO2 in the air is going to lead to catastrophic global warming.
NARRATOR: But what do we really know about the greenhouse effect?
JAMES TREFIL, George Mason University: You're dealing with something
where there is legitimate uncertainty in the science.
NARRATOR: Is there a real solution to our dependency on fossil
fuels?
MARTY HOFFERT, New York University: If humankind is going to have a
future on this planet, it is absolutely inevitable that we are going to have to
find another energy source.
NARRATOR: And does America and the world have the political will to
tackle what could become the most troubling issue of the 21st century?
FRED PALMER: The notion of reducing carbon dioxide emission levels by
the year 2010 is a complete fantasy. We are not going to do it, as a
society.
NARRATOR: Tonight PBS's premier science and investigative series join
forces to investigate the truth about global warming.
For most of history, humans believed that the weather was governed by forces
outside their control, but today we're no longer so sure. Something weird,
it's claimed, is going on with the weather, from storms and hurricanes to
droughts.
Vice Pres. AL GORE: Withering heat waves in Texas and in Florida,
cities that are setting thousand-year records for high temperatures- how much
more proof do we need that global warming is real?
NARRATOR: And the future, some argue, could be apocalyptic, as ice caps
melt and sea levels rise as much as 20 feet.
DAN LASHOF, Natural Resources Defense Council: Over the last few years,
you begin to get increased probability of extreme events. You're beginning to
get a sense that these are happening more than they used to. And people are
beginning to connect that with global warming.
NARRATOR: Vice President Gore is so convinced humans are warming the
planet, he advocated an international treaty committing America to drastically
reduce emissions from oil, gas and coal.
Burning these fossil fuels, he argues, puts greenhouse gases into the
atmosphere which trap heat and warm the globe. His opponents object that the
risks are exaggerated and any attempt to limit or get rid of oil, gas and coal
-which provide 90 percent of our energy - will cause an economic apocalypse,
from job losses to recession.
FRED PALMER, Western Fuels Association, Inc.: This is the United States
government identifying with a policy that would be devastating. What the
long-term goal of the vice president of the United States is to ultimately
eliminate all fossil fuel use in the United States. That is their goal.
NARRATOR: At the heart of this contentious issue is a battle for the
truth. When we strip away the rhetoric and politics, what does science really
know about global warming? The question has pushed the once obscure science of
climatology into the spotlight. But the climate system has turned out to be
very complex.
TOM M.L. WIGLEY, Nat'l Center for Atmospheric Research: Now we're
getting near the end of the run, where the CO2 level is much more than double
present day, and-
NARRATOR: And scientists' pronouncements about the future of the planet
vary widely as they struggle to determine whether the changes in the climate
are natural or caused by human beings.
TOM M.L. WIGLEY: A 5-degree warming will just change the whole climate
system radically. Precipitation patterns will be entirely different. The
amounts of precipitation will be entirely different.
PAT MICHAELS, Cato Institute: The climate changes, whether or not human
beings have something to do with it. You know, there's- there's this little
anomaly called the Ice Age. The Earth's climate naturally goes from its
current state to having 5,000 feet of ice over Chicago. The climate is
unstable.
NARRATOR: Tonight NOVA and FRONTLINE set out to uncover the truth about
global warming. A lot is at stake.
SEN. FRANK MURKOWSKI, (R) Alaska: Any new climate treaty must not
result in serious economic harm to the United States. What could be more basic
than that?
NARRATOR: From the wealth of nations to the future of the planet: Are
humans warming the globe? Or are we an insignificant influence compared with
the natural forces which have determined the climate for millions of years?
JAMES TREFIL, George Mason University: If you sat down and said, "I'm
going to design a public issue that is the absolute worst nightmare of every
scientist, of every communicator in the world," you couldn't do better than the
greenhouse effect.
You're dealing with something that's very complicated. You're dealing with
something where there's legitimate uncertainty in the science. It's not that
people are trying to pull the wool over anybody's eyes. There's legitimate
uncertainty. You're dealing with something that has enormous consequences for
people. And you're dealing with something whose effects will happen 30 years
down the road, you know, when they happen.
And then you say- you give people this and say, "Okay, do something about
it."
TOM BROKAW, NBC News: It is, in fact, a heat wave of global and
historic proportions, more than-
NARRATOR: The issue is typically framed in the media as a simple
question: Is it getting warmer?
DAN RATHER, CBS News: Final figures in from Canada today show October
'98, was the warmest October on Earth on record.
JAMES TREFIL: Unfortunately, when people talk about global warming,
it's always in terms of, "Oh, gosh, it was hot last summer." And that doesn't
work because weather and climate are two very different things. Climate is
sort of long-term things. Weather is short-term- daily, hourly, monthly,
whatever. And what we're talking about when we talk about the greenhouse
effect is we're talking about climate.
NARRATOR: James Trefil is a physicist and science writer who has
followed the global warming issue closely.
JAMES TREFIL: In order to say it is actually getting warmer now, you
have to know what it's been in the past and you have to know that what you're
seeing is not just a fluctuation. I mean, I remember when I was a kid, in the
50's, hearing stuff about the coming ice age because there was- we were in a
kind of a little cold snap then. And people- I remember pictures on the covers
of magazines showing glaciers moving down across American cities.
So if you take any short-term timeline, any short-term database for temperature
and extrapolate it, you can get crazy results. In order to make an
incontrovertible case for global warming, you'd have to have a long-term
temperature record, centuries, that was over a large part of the globe. And so
you have to look over a long term and say "What's the average been for several
hundred years, and is this a significant departure from that?" And that's
what's very difficult to do.
NARRATOR: Bad weather in one place at one time does not prove the
climate is changing. To prove humans are warming the globe requires detailed
knowledge of the entire Earth's weather over long stretches of history. And
this has turned out to be an enormously complex scientific challenge.
The Earth is a big place. Three quarters of it is covered by water. There are
giant ice caps and deserts and mountains. But climate scientists somehow need
to take the Earth's global temperature.
Today the Earth's weather is measured daily all over the globe by an
international network of stations on land and sea which report temperature,
pressure, rainfall, humidity and a host of other variables. Such global
measurements are the prime data base for climatology.
Millions and millions of figures have been collated, corrected, adjusted and
synthesized. The problem is, these measurements have only been taken
systematically for a century. When averaged, a pattern emerges. During the
past 100 years, the global surface temperature has risen by one degree
Fahrenheit, or about half a degree Celsius.
This is a temperature record of the entire Earth's surface, not just the
weather in one place. But is a 1-degree rise over a century a little or a
lot?
JONATHAN OVERPECK, Nat'l Oceanic and Atmospheric Adm.: What's really
remarkable about the warming over the last century is both its magnitude, in
terms of half a degree Celsius, and it's the fact that it has been almost
worldwide. Almost every site you look at has warmed dramatically since the
middle of the last century. [www.pbs.org: The debate on man's impact on
warming]
NARRATOR: But not everyone's convinced this is evidence that humans are
warming the globe. Fred Singer, an atmospheric physicist, is one of a small
band of scientists who have become known as greenhouse skeptics. He argues
that the 100-year record is not what it appears to be.
FRED SINGER, George Mason University: The data are ambiguous. For
example, the data show that the climate warmed between 1900 and 1940, long
before humanity used much energy. But then the climate cooled between 1940 and
1975.
NARRATOR: Only in the last few decades do rising global temperatures
seem to coincide with the greenhouse gases we put into the atmosphere.
Skeptics like Singer have also argued that long before the industrial
revolution, the climate warmed naturally. For example, records show that in
the Middle Ages, parts of the world, like Greenland, were warmer than today.
The Vikings built settlements there and farmed the land.
FRED SINGER: The Vikings were able to grow crops, and life was good in
Europe. Cathedrals were being built. There was plenty of food.
Climate change is a natural phenomenon. Climate keeps changing all the time.
It's either warming or cooling.
NARRATOR: But records of one place, like Greenland, during one time,
the Middle Ages, may not prove anything. Only by knowing the average global
temperature 1,000 years ago can scientists know whether the Earth back then was
warmer or colder than today.
JONATHAN OVERPECK: What we're looking for is a period in the past - or
periods - that are as warm or warmer than today because, of course, if they
were that warm, they were probably that warm due to natural processes. And
that might give us some clues about what natural processes, as distinct from
human ones, could be causing the warming today.
NARRATOR: Long before thermometers were invented, human beings recorded
the weather, sometimes in great detail. And these records are now being
scrutinized by climate historians.
CHRISTIAN PFISTER, Environmental Historian, Univ. of Bern: Weather was
an extremely important variable in daily life, and most people worked outdoors
and they were outdoors for most of the day. They were much more vulnerable,
and they knew it. And for this reason, there was extreme interest in any kind
of predictions.
NARRATOR: Throughout history there have been people who documented
events regularly and meticulously- physicians, artisans, and the monks here at
Einsiedeln in Switzerland. They recorded the time the cherry blossom appeared,
the freezing and thawing of lakes, the state of the wine harvest.
CHRISTIAN PFISTER: For instance, a very early cherry blossom is always
related to a very warm month of March. If the Lake of Zurich is completely
frozen, we know it is the equivalent of two extremely cold months always
because we know it from the period when we have both the observations and the
measurements.
NARRATOR: From these diverse records, climate historians can glean a
lot about the past climate. By combining data from many sites, this clever
forensic work can yield a detailed picture of areas like central Europe going
back more than 1,000 years. Has Pfister found any period in the past as warm
as the 1980s and '90s?
CHRISTIAN PFISTER: We had other periods which was also very warm, but
it was equivalent to the 20th century prior to 1988. I would say this was a
period of warm climate, but I would say it was a period of warm natural
climate. With the period between 1988 and 1997, there's absolutely no
equivalent as far as I can look back.
NARRATOR: But this technique, too, is limited. Only a few areas, like
Europe, have long-term records which survive. To get a handle on the global
climate, scientists have been forced to go beyond human accounts of the
weather.
Five hundred miles from the North Pole, a frozen lake will be home to a team of
scientists for the next few weeks. It's part of an international effort to try
and reconstruct the climates of the past.
RAYMOND S. BRADLEY, University of Massachusetts: We are here in the
Canadian high Arctic, on Ellsmere Island, about 500 miles from the North Pole.
And it might seem strange that we would come to this kind of environment to
study the problem of global warming. But what we need to do is try to
reconstruct the longer-term history of climate, and we do that by using
so-called natural archives of climate, things that in some way retain in their
structure a measure of how the climate has varied in the past.
NARRATOR: Bradley and his team will spend the brief Arctic summer
drilling through the ice and sampling the pristine sediments at the bottom of
Lake Tuborg.
RAYMOND S. BRADLEY: Because the lake is frozen over for most of the
winter, what we have is a very brief period during the summer when the snow
melts and the sediments are carried into the lake. And that settles out into
the lake, and it forms these layers, just like the layers you see in a tree
ring or in an ice core. Year by year, we get a nice sedimentary record.
NARRATOR: These year-by-year variations in thickness will be used to
estimate past temperatures at Lake Tuborg. A thicker layer means there was a
warm spring which melted more snow and produced more mud. This expedition
yields temperature information going back hundreds of years, but in just one
location. To estimate the past average global temperature, such measurements
must be made all over the Earth's surface.
Thirty-five hundred miles to the south, a team from Scripps Institution of
Oceanography are examining the trees in Mammoth Park, California. Franco
Biondi and his colleagues have done this many times.
FRANCO BIONDI, Scripps Institution of Oceanography: The way the trees
grow, they will cover themselves entirely every year with a new layer of wood.
And if you take a horizontal section, you're going to see the width of each one
of these layers.
NARRATOR: Because trees grow all over the world, they are one of the
most powerful natural recorders. Their annual rings not only give scientists a
built-in date, they also contain a record of past temperature and
precipitation.
FRANCO BIONDI: Each one of these layers is an annual layer seen in
cross-section. The annual layer is formed by these two portions together, the
early wood and the late wood. And the width of the layer is our first
indication of a climate pattern. So the narrow band that you see here
indicates a year when the winter and spring were drier than normal. And then
the larger layers that you see here indicate a period when winter and spring
precipitation were more abundant than normal.
NARRATOR: Trees are very common on land, but for the three quarters of
the planet covered by ocean, scientists need other recorders. Like trees,
corals can live for hundreds of years and grow at different rates, depending on
the temperature at the sea surface. The Earth's temperature is also preserved
in the chemistry of ice layers extracted from glaciers all around the world.
Each natural recorder produces estimates of temperature and rainfall for a
given place and time. Combining them all, scientists have been able to extend
back the temperature record for the northern hemisphere about 1,000 years.
According to this graph published in 1999, the 20th century's one degree
warming stands out dramatically. [www.pbs.org: Visit the "stories in the
ice"]
But what about Greenland and its controversial medieval warm period? According
to the combined data, there was no medieval warm period. Specific regions like
Greenland may have been warm, but the average global temperature back then was
cooler than today.
Even though the data is preliminary, Bradley is convinced the climate of the
20th century is unprecedented.
RAYMOND S. BRADLEY: We think this warm period 1,000 years ago was just
a regional anomaly. We find almost no period in that whole 1,000 years which
has temperatures as high as we've seen in the last part of the 20th century.
And in particular, the 1990s were exceptionally warm. It was an incredibly
unusual decade, and we have no evidence that there was a decade quite like the
1990s all the way back 1,000 years.
NARRATOR: If this finding holds up, does it prove humans are causing
global warming? Some greenhouse skeptics like MIT's Richard Lindzen urge
caution.
RICHARD S. LINDZEN, Mass. Institute of Technology: Well, it leaves out
a couple of things. First of all, one has to distinguish the statement
"warming," meaning temperature has gone up, from "warming," meaning man has
caused temperature or something has caused temperature to increase.
NARRATOR: How can we be sure that recent warming is man-made rather
than natural? And what evidence is there to link this temperature increase to
human activity?
Perhaps no man has done more to help answer this question than Charles David
Keeling. Forty years ago, nobody knew for sure whether industrial greenhouse
gases like carbon dioxide were increasing in the atmosphere or whether they
were being absorbed by the oceans. In 1957, Keeling set out to discover which
was right. Taking advantage of the special funding available in the
International Geophysical Year, he set out with the latest analyzers to begin
what would become his life's work.
CHARLES D. KEELING, Scripps Institution of Oceanography: This program
afforded me an opportunity, even though I was just out of school, practically,
and a very young man, to, commandeer enough resources to see that these
analyzers were put in several places, and rather quickly at that. One analyzer
was put in Little America Antarctica, and shortly after, another one was placed
on a mountain in Hawaii called Mauna Loa.
NARRATOR: The ideal place to measure carbon dioxide is away from
cities, which produce it and distant from vegetation, which absorbs it. On the
Hawaiian mountain of Mauna Loa, Keeling found the ideal spot. Located at
11,000 feet in the midst of a barren lava field, he began to sample the Earth's
air.
CHARLES D. KEELING: At Mauna Loa Observatory we started the
measurements in March, 1957, and I expected the concentration would be perhaps
almost dead constant, knowing nothing else as a hypothesis, but that wasn't
what happened. The concentration rose for several months, and then it dropped.
And it dropped all during the period from May until September. And then it
started to rise again.
As soon as we saw that much information, less than a year's worth of data, it
was pretty obvious that we were looking at the breathing of the plants in the
northern hemisphere because they absorb carbon dioxide during their growing
period in temperate and high latitudes, and then it's released again in a
cyclic process in the wintertime.
NARRATOR: Keeling's sensitive measurements had picked up the Earth's
respiration. Every spring, plants bloomed, sucking carbon dioxide out of the
air. Every fall, CO2 was released back into the air as the plants decayed.
But Keeling noticed that year by year, the total concentration of CO2
increased. Superimposed on the annual cycle was a rising curve. Each year,
more CO2 was inhaled and exhaled by the biosphere. Over 40 years, the
concentrations rose from 330 parts per million to almost 370 parts per million.
The Keeling curve appeared to prove what many had suspected, that humans were
changing the composition of the atmosphere.
But why should adding an invisible, non-toxic gas be cause for concern?
Compared to the major atmospheric gases - oxygen and nitrogen - the amount of
CO2 is minuscule, but through an accident of physics - the greenhouse effect
-its consequences are significant.
Perhaps the most dramatic example of the greenhouse effect is the Earth
itself. But for this effect, the Earth would be frigidly cold. Of the energy
coming from the sun, about half of the light gets scattered and absorbed before
it reaches the surface. The rest is radiated back as heat or infrared
radiation.
In the absence of a greenhouse effect, this heat energy would escape back into
space, leaving the Earth with an average temperature of zero degrees
Fahrenheit. All water would freeze. The reason this doesn't happen is that
greenhouse substances - gases like carbon dioxide and methane - and water vapor
and clouds - all act to trap escaping infrared radiation. The net effect is
to cause the Earth's surface to warm up to an average of 59 degrees.
RICHARD C. J. SOMERVILLE, Scripps Institution of Oceanography: It's as
real as gravity, and it keeps the planet habitable. We'd have an average
surface temperature on the Earth below the freezing point of water were it not
for the greenhouse effect.
NARRATOR: But since the industrial revolution, there has been a new and
growing source of CO2: fossil fuels like coal, oil and natural gas. When
fossil fuels are burned, their carbon atoms combine with oxygen in the air to
make CO2. Every time we turn on a light or drive our cars, we are adding CO2
to the atmosphere. [www.pbs.org: What's your carbon diet?]
CHARLES D. KEELING: It's hard for people to understand how much carbon
dioxide is being put into the atmosphere in absolute terms, but in relative
terms we can say as follows: At the end of World War II, about a billion metric
tons of carbon, in the form of CO2, was being emitted to the atmosphere. When
I started my measurements, it had risen to two and a half. At the present
time, it's almost seven.
NARRATOR: According to the theory of the greenhouse effect, adding more
greenhouse gases like CO2 to the atmosphere should cause the average global
temperature to rise for as long as we continue burning fossil fuels.
The climates of Mars and Venus were also shaped by the greenhouse effect.
PIETER TANS, Nat'l Oceanic and Atmospheric Adm.: Venus has an extremely
high concentration of CO2 in its atmosphere, and it's blazing, boiling hot at
the surface of Venus. And the Martian atmosphere, for instance, is very, very
thin. And also within that thin atmosphere, there's only very small amount of
CO2. And water vapor is also very, very low. And the surface temperature of
Mars is frigid- very, very cold.
NARRATOR: In the contentious debate about man-made global warming, all
sides agree on the physics of the greenhouse effect. It can even be
demonstrated in the lab using a FLIR thermaCAM, a special infrared camera.
PIETER TANS: So we're going to demonstrate to you how the CO2 absorbs
infrared radiation, which causes the Earth's greenhouse effect. Infrared
radiation is another word for heat radiation, which is coming off of my face,
and which is picked up by a camera that I'm looking at. The camera is
sensitive to heat radiation. Between me and the camera is a volume that we
will fill with CO2 gas, and as we turn on the gas, my image will slowly
fade.
NARRATOR: This physical property of CO2, known to physicists for a
century, is the bedrock of the concern about global warming. Because the
ordinary air in the tube, composed mainly of nitrogen and oxygen, does not
block infrared radiation, the camera sees the heat coming off the scientist's
face clearly.
PIETER TANS: And as we turn on the gas, my image will slowly fade.
NARRATOR: But when the tube is filled with CO2, or any greenhouse gas,
their molecules absorb the heat radiating off his face, blocking its path. As
less and less heat reaches the camera, the image fades. If the scientist were
surrounded on all sides by CO2, then the effect would be for him to get warmer,
like the Earth in space.
Today the atmosphere is sampled at many sites on land and sea. Flasks are
filled and sent to central laboratories like the National Oceanic and
Atmospheric Administration lab in Boulder, Colorado, to be analyzed for CO2 and
other greenhouse gases. Even though most of the CO2 is put into the atmosphere
in the industrial northern hemisphere, analysis reveals it pretty soon shows up
everywhere.
PIETER TANS: If you burn, say, a gallon of gasoline that is turned into
CO2 molecules, it will spread throughout the entire atmosphere. So what you
burn today in your car will show up in Antarctica by next year.
NARRATOR: The other important fact scientists have discovered about CO2
is its permanence. Unlike water vapor, which stays around only for days, CO2
remains in the atmosphere for, on average, 100 years before being absorbed by
the oceans. Our CO2 emissions are therefore changing the atmosphere not just
for us but for future generations.
The measurements at Mauna Loa had produced clear evidence that humans were
changing the composition of the atmosphere. But the data went back only 40
years, while we've been burning fossil fuels for more than 150 years, all
during the industrial revolution. Just as scientists had used natural
recorders to get at past temperatures, they now wondered if the giant ice
sheets in Greenland and Antarctica might have captured past CO2 levels during
and before the industrial revolution.
And what they found was remarkable. Trapped in the ice cores are bubbles of
air, time capsules preserving the atmosphere of the past. With care, these
bubbles of fossilized air can be analyzed for carbon dioxide and other gases.
Sensitive analysis of the air bubbles reveals that before 1957, the atmosphere
had less CO2. Indeed, CO2's rapid rise starts at the beginning of the
industrial revolution.
Subsequent research has extended the curve far back in time. It's now
established that current levels of CO2 are higher than at any time for the past
450,000 years.
MICHAEL B. McELROY, Harvard University: When you look at a 450,000-year
record, and the last 100 years, 150 years, stands out like a sore thumb,
there's not much question that we're involved in some way or another. And
truly, that's not surprising. I mean, we are such an incredibly powerful force
on this planet- our species. I mean, most of the land area of the Earth that
is habitable, that is cultivable, we've cultivated or we've inhabited. We've
moved mountains. We've redirected rivers. We've mined all this coal. We're a
global force.
FRED SINGER, George Mason University: I have no doubt that an increase
in carbon dioxide in the atmosphere should lead to some increase in global
temperatures. The question is, how much? And how can we be sure that any
temperature increase that we do find in the record is, in fact, due to this
additional carbon dioxide? Since we know that the climate also changes
naturally - it warms, it cools - how can you distinguish a warming produced by
an increase in carbon dioxide from a warming produced by some other cause,
let's say by the sun?
NARRATOR: The argument that fossil fuels are changing the climate has
alarmed coal, gas and oil producers. Because so much is at stake, the energy
industry have been following the scientific arguments closely.
FRED PALMER, Western Fuels Assn., Inc: I understand that people get
uneasy over the concept of more CO2 going into the air, but you can't live your
life based on speculation. And we know today that using fossil fuels is a good
thing. It leads to economic growth. It allows more people to live longer on
Earth. These are- there are positive goods that come from using fossil fuels.
There's a speculative "bad" that people are holding out there, saying,
"Therefore. let's stop using fossil fuels." And I think that's an imprudent
approach.
NARRATOR: The coal industry has mounted an aggressive challenge to the
whole idea of human-induced climate change. Its high-powered public relations
campaign argues that CO2 has been unfairly characterized as a pollutant.
FRED PALMER: In the past, we've had these great struggles over
pollution in the United States. Sulfur dioxide is a pollutant. Nox (sic) is a
pollutant. Carbon dioxide is a benign gas required for life on Earth. It is
not a pollutant. It is not regulated. There are no state laws dealing with
CO2. There are no congressional laws that give an agency the right to regulate
based on CO2.
NARRATOR: Far from being a pollutant, the coal industry argues, CO2 is
a powerful plant fertilizer, so producing more of it will green rather than
pollute the planet. Its video The Greening of Planet Earth maintains
that industrial CO2 will fertilize the Earth, and the enhanced forests will
eventually soak up the excess greenhouse gas.
ANNOUNCER: ["The Greening of Planet Earth"] Grasses will grow
where none grow now, and great tracks of barren land will be reclaimed.
NARRATOR: It argues that horticulturists pump CO2 into their
greenhouses - time times current atmospheric levels - to make the flowers and
vegetables grow faster. And indeed, the plants thrive. The industry believes
that characterizing CO2 as a fertilizer rather than a pollutant turns the
controversy on its head.
FRED SINGER: The only thing we are concerned about is carbon dioxide
levels becoming too low because if carbon dioxide levels were to fall below,
let's say, one half of the present level, as they almost did during the last
ice age- if they were to fall below one half of the present level, then plants
would be in real trouble. After all, carbon dioxide is plant food. Without
carbon dioxide in the atmosphere, plants would disappear.
NARRATOR: While it's accepted that CO2 is a plant fertilizer, it's not
known just how the world's forests will react. Will they be able to keep up
with ever-increasing CO2 emissions? In a remarkable series of federally funded
experiments, scientists are trying to test the greening hypothesis. In 50
years, if current trends continue, CO2 concentrations will be double the
pre-industrial level. And that's just what this forest is getting.
WILLIAM H. SCHLESINGER, Duke University: Our experiment is an attempt
to grow an entire forest at 560 parts per million. In other words, we're
replicating the growth of forest 50 years from now around the world, when all
forests will be bathed in that atmosphere. We're essentially jetting CO2 into
the forest.
NARRATOR: Doing science on this scale is a massive undertaking.
WILLIAM H. SCHLESINGER: Each of the experimental plots consists of a
row of towers that inject carbon dioxide 24 hours a day, 365 days a year.
NARRATOR: As the trees grow, carbon dioxide flows in and out of the
forest, some carbon getting locked up as wood, some decaying back into the
atmosphere. So everything in this forest of the future must be carefully
measured.
Only two years into the experiment, the scientists can already see some
changes.
WILLIAM H. SCHLESINGER: As a result of the first two years of the
experiment, the 1997 and 1998 growing seasons, we found a 25 percent growth
rate increase in the loblolly pine exposed to high carbon dioxide in the
forest. Whether or not that continues is a real source of interest to us.
NARRATOR: So is the coal industry right? Will this enhanced growth
help suck up the excess CO2? Only, say scientists, if the CO2 stays out of the
atmosphere.
PIETER TANS, Nat'l Oceanic and Atmospheric Adm.: The forests might
sequester CO2 for 50 years, 100 years. And then at a certain point, it comes
more or less into balance because enough organic matter in the forest has been
built up that decay starts to catch up with photosynthesis. If we chop down
the old tree, we have to make sure that most of that tree is put into a usable
product that has a long life. And what happens then? Eventually the lumber
rots or gets burned.
NARRATOR: Eventually, within a century or less, the carbon locked in
wood will find its way back into the atmosphere as CO2. And there's another
reason for believing that plants alone can't absorb all the CO2: the vast size
of the fossil fuel reserves.
PIETER TANS: When you look at the amount that is potentially available
in coal, it's such an overwhelming amount. If you were to store all that in
plants, the terrestrial biosphere would be four or five times the mass that it
is now. Hard to conceive how plants could keep this up, you know, over
centuries.
NARRATOR: But even without the "Greening of Planet Earth" theory, the
fossil industry is unwilling to concede that increased CO2 will translate into
major climate change.
FRED PALMER: There are reasonable people that have speculative fears
about more and more CO2 going into the air and impacting climate. But there is
no basis, no mechanism that anybody can point to or look at to say that more
CO2 in the air is going to lead to catastrophic global warming or apocalyptic
global warming, as opposed to some mild warming, which is nothing to be
concerned about at all.
NARRATOR: It's not disputed that CO2 levels are a third higher today
than before the industrial revolution and will double and perhaps triple in the
next 100 years. The real crux of the issue is how precisely this rapid rise
will affect the Earth's climate and whether those changes will be bad or
good.
The National Center for Atmospheric Research, NCAR, in Boulder, Colorado, is
one of the world's top centers for climatology. Inside, there are scientists
whose job is far harder than any weather forecaster. They must try to predict
the climate a century into the future.
Tom Wigley is one of NCAR's climatologists. Wearing special 3-D goggles,
Wigley and colleagues can look at models of possible future climates.
RESEARCHER: The white is showing cloud ice and the colored surface in
the center is relative vorticity, and it's being colored for temperature. So
we have an iso-surface vorticity, and then temperature colored on top of it.
NARRATOR: The pictures on the screen are conjured up by supercomputers.
These high-tech crystal balls offer the only means of thinking through the
climate consequences of a world in which CO2 levels are double or triple what
they are today.
A climate model starts by trying to capture all the many factors, natural and
human, which can affect or force the climate system, either trapping or
reflecting energy.
TOM M.L. WIGLEY, Nat'l Center for Atmospheric Research: There are
really three categories of factor that one has to consider. One is the
influence of human activities, the build-up of carbon dioxide in the atmosphere
and other greenhouse gases, and also the effect of sulfate aerosols. Aerosols
are very small droplets that are primarily made of sulfuric acid or ammonia
sulfate that are suspended in the air. And they arise from fossil fuel
combustion, and those particles have a cooling effect.
The next important issue is what about natural external factors that might
cause temperature to change on a global basis. We know from satellite
measurements that the sun changes on a decadal time scale. The other external
influence is volcanic eruptions, and the prime example there was Mount
Pinatubo, that erupted and caused for a year or two a substantial amount of
cooling.
In addition, there are other interactions that are going on purely internally
within the climate system. As the amount of heat in the atmosphere is
transferred to ice masses or to the ocean, that could cause, for example, the
globe to warm by one or two tenths of a degree or cool by one or two tenths of
a degree over a 100-year period.
NARRATOR: The many processes which push and pull the climate system are
fed into the supercomputers. Then things get even more complicated. The
climate's ultimate response depends on a complicated chain of feedbacks that
can either amplify or diminish the original warming or cooling.
TOM M.L. WIGLEY: We are at the point now where the amount of carbon
dioxide is roughly double the present level and-
If we were to add carbon dioxide to the Earth's atmosphere and cause warming,
then the oceans would warm, and the amount of water evaporating from the oceans
would increase. And it happens that water vapor is also a powerful greenhouse
gas. So that by putting carbon dioxide into the atmosphere, we increase the
amount of water vapor, and so we increase the total amount of greenhouse gases
in the atmosphere and amplify the effect of carbon dioxide alone.
RICHARD C. J. SOMERVILLE, Scripps Institution of Oceanography: Here's a
straightforward example. You first warm the climate for whatever reason, and
then the chain is, snow and ice melt, a darker surface is exposed. That darker
absorbs more sunlight than did the snow and ice that was there before, and
therefore the climate warms even more. It's a positive feedback. It's as
though you had the thermostat in your house set so that when the house warmed
up, it turned on the furnace and warmed it up still more.
NARRATOR: But some feedbacks, like clouds, are more complex.
WARREN M. WASHINGTON, Nat'l Center for Atmospheric Research: If a
low-level cloud is generated, then that shields the surface from the sun, so
that you get less solar radiation arriving at the Earth's surface. So that's a
negative feedback. However, if you generate more high clouds, then those
higher clouds can actually help to trap the infrared radiation leaving from
the surface and warm up the system.
NARRATOR: NCAR is just one of a dozen scientific groups who have tried
to incorporate all these feedbacks into their computer models. Under pressure
from policy makers, they have tried to predict what will happen to the Earth's
climate when CO2 doubles in the atmosphere. All the models predict the Earth
will warm, but the wide range of predicted temperature increases has drawn
criticism from greenhouse skeptics.
FRED SINGER, George Mason University: These models are all produced by
very competent people, excellent meteorologists, fantastic computers. Why do
they not agree? Why do some models predict a warming for a doubling of CO2 of,
let's say, 5 degrees centigrade, which is 8 degrees Fahrenheit, and why do
other models predict something like 1 degree?
NARRATOR: The different predictions reflect real gaps in knowledge
about the Earth's climate. If the water vapor and cloud feedbacks are strongly
positive, as some modelers assert, then a huge climate change of up to 8
degrees Fahrenheit is to be expected. If this feedback is weak, as some
skeptics argue, then a rise of only a degree or so will occur.
RICHARD S. LINDZEN, Mass. Institute of Technology: If you didn't
amplify what CO2 did with having water vapor and clouds go along with it, you'd
only at most get a degree or so.
INTERVIEWER: With a doubling?
RICHARD S. LINDZEN: With a doubling. And tripling would not do much
more. And people have pretty much accepted this would not be a major change in
the world as we know it.
NARRATOR: The computer models tell of possible futures, some scary,
some less so. Which is true? Currently, there's no way to know.
JAMES TREFIL, George Mason University: Computer models of climate are
the most complicated, ingenious computer systems I've ever seen. I mean, they
really are good. But in the end, you have to just face the fact that they are
not going to be able to give you precise, certain answers. They're going to
give you, "We think this is what's going to happen, and here's the limits of
error." And that's the uncertainty, and you have to choose.
NARRATOR: If the scientists are uncertain about the precise global
temperature increases, they know even less about the specific effects the
warming will produce. Of greatest concern is sea-level rise caused by melting
glaciers and thermal expansion of warmer water. Coastal areas from Venice to
California would then be vulnerable.
KEVIN E. TRENBERTH, Nat'l Center for Atmospheric Research: Off the
coast of California during El Nino events, the sea level rises. And in the
last El Nino event, it was about eight inches above the normal value. And what
we saw was a lot of coastal erosion, houses toppling into the sea. And so
that's sort of an indication as to what increases in sea level can do.
We can adapt to a climate change, as long as it occurs slowly enough. But if
it occurs too rapidly, then it disrupts the assumptions that we've built into
the way in which society works, whether we are planning agriculture, whether
we're planning a building with its heating requirements, whether we're planning
a dam.
NARRATOR: If such human-induced climate effects occur, rich nations may
be able to adapt and build sea walls. But for some countries, this isn't an
option, like the 1200 low-lying Maldives Islands, isolated in the Indian
Ocean.
ISMAIL SHAFEEU, Gov't Official, Republic of Maldives: All of these
islands are totally flat. The average height above sea level is about a meter.
And they're totally exposed to the sea. If there is even a minute change in
the level of the sea, or a change in the size of the waves that come into our
shores because of increased incidence of hurricanes, typhoons, we are all dead.
The impact of global warming and climate change can effectively kill us off,
make us refugees, lose every bit of land that we have available to us right
now. [www.pbs.org: What other land could be submerged?]
NARRATOR: But greenhouse skeptics think such scenarios are alarmist.
Modest warming, they argue, may even be good.
FRED SINGER: We have to ask what are the impacts of a warmer climate?
What is the impact on agriculture? The answer is, it's positive. It's good.
What's the impact on forests of greater levels of CO2 and greater temperatures?
It's good. What is the impact on water supplies? It's neutral. What is the
impact on recreation? It's mixed. You get, on the one hand, perhaps less
skiing. On the other hand, you get more sunshine and maybe better beach
weather.
Let's face it, people like warmer climates. There's a good reason why much of
the U.S. population is moving into sun belt, and not just people who are
retiring.
NARRATOR: But most climate scientists are less optimistic.
STEPHEN H. SCHNEIDER, Stanford University: We're talking about humans
modifying the climate so that, if we're lucky, we only get another degree in
the next century. And it could be several degrees per century, is our best
guess.
Compare that to the degree per millennium of history, and now ask one more
factor. How are the species of trees, for example, and birds and so forth- how
are they going to migrate? In history, they just migrated. Now they have to
cross factories, farms, freeways and urban settlements.
So if you have the combination of fragmented habitats with nature getting into
smaller and smaller patches, now you've changed the climate 10 times faster
than the history for which they have experience. This seems to me an absolute
prescription for an extinction crisis.
NARRATOR: And some scientists caution there's a possibility that even
modest warming might trigger major climatic changes by destabilizing the
currents of the oceans.
The oceans are the wild card in the climate system. By carrying warm water
from the equator to the north Atlantic, currents like the Gulf stream have a
tremendous impact on the Earth's climate. By the time the Gulf stream has
reached the north Atlantic, the water has given up its heat. The now cold and
salty water is so heavy it sinks to the bottom and returns to the equator to
form a closed circulation.
RON PRINN, Mass. Institute of Technology: These circulations are
responsible for taking water from the top of the ocean down to deep levels in
the ocean, in some cases right to the bottom. In doing so, in the present
circumstances, this is a way of getting heat into the ocean and also a way of
getting carbon dioxide buried in the deep ocean. So it's doubly important,
this circulation, for the climate issue.
NARRATOR: But for this, the climate in Europe would be very
different.
MICHAEL B. McELROY, Harvard University: Think of the climate in the
British Isles or in southern Norway. It's a mild climate. You can play golf
in Scotland in January. But what's the latitude of northern Scotland? I mean,
bring it over to the United States and you're are sitting in the middle of
Hudson's Bay.
NARRATOR: What worries some scientists is that in the past, this
circulation appears to have stopped. A close examination of polar ice cores
reveals about 10,000 years ago, while the Earth warmed up from the last ice
age, the climate suddenly switched back into a cold state. Temperatures fell
nearly 10 degrees in a decade. Some scientists believe it was caused when
fresh water from melting glaciers flowed into the north Atlantic and disrupted
the ocean circulation.
What might happen if today's global warming caused the circulation to stop?
RON PRINN: First, the north Atlantic would get much colder than it is
today. That would mean Europe, northern Europe, would cool down very rapidly.
If that kept up over time, one would get more and more snowfall over time. And
one of the hypotheses for going into an ice age is a shutdown of just that
circulation, leading to more and more snowfall. Then it accumulates. It lasts
over the summer. And steadily, over hundreds, thousands of years, you can
build up glaciers on land that was previously, you know, vegetation-covered.
Paradoxically, a warming, in that case, would be leading to a catastrophic
cooling of some parts of the world.
NARRATOR: The mighty oceans, some scientists argue, are the biggest
uncertainty in the climate system, capable of dramatic climate surprises.
After decades of research, climate scientists have presented many possible
scenarios for the future of the planet. Because of uncertainties about effects
of all the feedbacks - involving atmosphere, ice caps and oceans - they still
can't say precisely what will happen.
STEPHEN H. SCHNEIDER, Stanford University: I can imagine so called
feedback processes where you if you warm up the Earth, you melt snow and ice,
which adds further warming. If you do that, it makes the clouds taller, which
makes them trap more heat, instead of wider. And if I conjure up these
feedbacks, I can end up expecting that we could have climate change that's
catastrophic in the next century.
I can also conjure up another set of feedbacks, the clouds get wider, that it
gets drier in between the clouds. There are a number of feedbacks that we can
conjure up which makes it warm up only a degree or so, at the relatively mild
end of the spectrum.
Well, most scientists would argue that these very mild and very catastrophic
outcomes are plausible, maybe even a 10 percent of each of them. But the bulk
of the likelihood is somewhere in between the end of the world and the "good
for you" scenarios that you see all the time in the newspapers and in the
congressional debates.
NARRATOR: While scientists remain unsure of how the climate will change
if CO2 continues to rise, they're certain we have already altered the
composition of the atmosphere. Continued burning of fossil fuels now poses a
credible threat to the climate. And since there are vast untapped supplies of
fossil fuels in the Earth's crust just waiting to be exploited, today's
greenhouse emissions might be eclipsed by what is to come.
PIETER TANS, Nat'l Oceanic and Atmospheric Adm: If we burned all the
coal in a couple hundred years, we would very likely increase the atmosphere in
CO2 concentration by more than a factor of 10. That's huge. There would be no
debate about anthroprogenic climate change, man-made climate change. It would
be clear as a bell.
Once we have driven up CO2 levels in the atmosphere, for it to come back down,
it would take a very long time. My timescale for that is thousands of years.
RICHARD C. J. SOMERVILLE, Scripps Institution of Oceanography: If a
skeptic says that he or she is not worried about doubling, ask them about
tripling or quadrupling. And ask them about all the other gases besides carbon
dioxide, some of which are increasing faster then CO2. There comes a point
when you can't escape the idea that you're having serious climatic
consequences. And so the issue becomes one of guessing whether we get wise
before that day, or whether we have to wait for some perhaps quite
unanticipated climate surprise that wakes us all up.
NARRATOR: The emerging consensus among climate scientists that global
warming was real became the fuel for a growing political movement to reduce
greenhouse gas emissions. The White House was at the center of this movement.
In October, 1997, Clinton and Gore invited 110 T.V. meteorologists to a global
warming briefing, hoping to recruit them as foot soldiers in the campaign.
Pres. BILL CLINTON: We have to say there's a challenge out there. We
have to respond to it. Here's the principles we want in our response. And
then we have to get after it. But we can't do it until we build the awareness
of the American people.
NARRATOR: But the White House point man on the issue, who had
championed it for decades, is Vice President Gore.
Vice Pres. AL GORE: This is coming, and we've got to do something about
it. Are we going to be a part of the problem or a part of the solution? If we
sit back and do nothing and allow this to happen without change, then what the
mainstream scientists from every country in the world are telling us is that
it's going to have profound changes in the pattern of climate and-
NARRATOR: Gore was trying to build public support because international
negotiations about global warming had reached a critical stage. In December,
1997, representatives from 160 countries met in Kyoto, Japan to attempt to
limit world greenhouse gas emissions. Environmental groups were out in force,
hoping that this meeting would begin a radical transformation.
DAN LASHOF, Natural Resources Defense Council: If we're going to solve
the problem of global warming, the United States has got to be a world leader,
just as we are on just about every other international issue. It's not a
problem we're going to solve overnight, but what we can do is change the
direction. Now every year emissions are higher than they were the year before.
We've got to turn that around and get into a situation where gradually but
steadily we're reducing our emissions of carbon pollution and other
heat-trapping gases. I think we can do that.
NARRATOR: Out of this meeting, it was hoped, would come binding
agreements to limit greenhouse gas emissions.
CONFERENCE DELEGATE: We know what we must do. We know it can only be
done together. So let us get on with-
NARRATOR: The fundamental issue at stake was the world's use of fossil
energy. Because the United States uses more energy than any other nation, it
would come under the greatest scrutiny. More than any other country, the U.S.
is accustomed to cheap energy on demand.
FRED PALMER, Western Fuels Assn, Inc: We are criticized for being the
highest per capita consumers of fossil fuels in the world. It's a positive
good. There's a correlation between our energy consumption and our success.
We don't succeed in the United States in spite of energy consumption, we
succeed in the United States because of energy consumption.
NARRATOR: Americans use one quarter of the world's energy. A vast
infrastructure delivers energy whenever and wherever it's needed. It works so
seamlessly that Americans have stopped thinking about where energy comes
from.
Most of it, in fact, comes from burning fossil fuels. Every time we turn on a
light, the odds are that the energy comes from burning coal. Close to 60
percent of all U.S. electricity comes from coal, so power stations must be
supplied 365 days a year with this most abundant fossil fuel.
FRED PALMER: People don't think a lot about coal, and they are not
required to think about coal. But Coal in the United States is the major
driver of our economy, in that it supplies 56 percent of electricity. One
1,500-megawatt coal unit supplies electricity for a million and a half
people.
NARRATOR: Coal generation is supplemented with other carbon-emitting
fossil fuels like oil and natural gas. Some sources of electricity produce no
greenhouse gases- hydroelectric power, solar energy, the power of the wind, and
the largest carbon-free source of energy, nuclear power, which currently
supplies over 20 percent of U.S. electricity. All these sources flow into
electricity grids, like this one managed by Northern States Power in
Minneapolis.
What few people realize is how much energy is being consumed 24 hours a day.
Even at 3:00 in the morning, 55 percent of the load is operating.
AUDREY ZIBELMAN, President, NSP Energy Marketing: Nothing totally shuts
down, and even at 3:00 o'clock, you have the street lights on. You have
factories that are working on a 24-hour period. And what we'll do at the night
time is run our cheapest units, our coal and our nuclear units. And those are
the units we call our baseload units that we use all the time. And they produce
the lowest-cost energy.
About 7:00 o'clock, our load will start to pick up as people get up and go to
work, and buildings start opening up and air conditioners go on. What we'll do
is turn on different generating plants as demand increases.
NARRATOR: All over America, the scene is the same. As the day gets
going, the demand for energy ramps up. And since most of this energy comes
from fossil fuel, it all adds greenhouse gases to the atmosphere.
Take the simple act of making toast. Over the course of a year, a toaster on
average consumes about 39 kilowatt hours of electricity. And each one of those
kilowatt hours sends about half a pound of carbon into the air.
JONATHAN G. KOOMEY, Lawrence Berkeley Nat'l Laboratory: When you
multiply that out, what you get is about 8 kilograms of carbon per year for
toasting bread every day. And if we convert it to pounds by multiplying by
2.2, we get about 20, 20 pounds of carbon per year associated with using a
toaster.
NARRATOR: Or consider central air conditioning.
JONATHAN G. KOOMEY: A typical home in the South would use about 4,000
kilowatt hours for air conditioning. If we convert that to carbon emitted, we
get about 800 kilograms of carbon emitted per year for a central air
conditioner. And that's about 1,800 pounds, which is more than the weight of a
small car like a Toyota Corolla.
NARRATOR: Since each pound of carbon entering the atmosphere combines
with oxygen to form nearly four pounds of carbon dioxide, America's
contribution to greenhouse gas build-up is even more striking.
Taking a shower each morning produces 550 pounds of CO2 in a year. Using a
computer 40 hours a week produces 600 pounds of CO2. Lighting an average house
for a year emits 2,000 pounds. Lighting an large office building not
surprisingly produces much more, 2.5 million pounds of CO2.
And about one third of all American greenhouse emissions come from
automobiles.
JONATHAN G. KOOMEY: People drive, on average, about 12,000 miles per
year, and a typical new car gets roughly 28 miles per gallon. That means that
you will use about 430 gallons per year. And so over the course of a year, the
person driving this new car will emit roughly 2,200 pounds of carbon per year.
That's roughly the weight of the car itself. Now, if you have an SUV, which
only gets 14 miles per gallon, you're emitting 4,400 pounds per year,
essentially the same as having two cars on the road instead of one.
NARRATOR: Apart from the energy we use to live, enormous amounts of
power are required to manufacture all the things we buy. Grede Foundries in
Minnesota needs as much electricity as a small town. And it needs this power
on demand.
WILLIAM NESTEL, Grede Foundries: Grede makes all steel and iron parts.
We make the rear end for the Dodge pickup trucks, and we make approximately
3,200 of those a day. We also make a powertrain component for the G.M.
vehicles, and we make about 10,000 of those a day. If we loose electricity, we
are dead in the water and we can't do anything.
NARRATOR: On any given day, Minneapolis-based Northern States Power
directs up to 8 billion watts of power to homes and businesses. It's the same
in most U.S. cities. Because of this energy consumption, each American on
average, directly or indirectly, puts over 20 tons of CO2 into the air each
year, collectively one quarter of the world total.
The energy use of industrialized nations like the US is responsible for the
dramatic one third increase of CO2 in the atmosphere. But that's nothing
compared with what is to come. The future of global warming will be determined
by what happens in the developing world, nations like Brazil, India and China,
where three quarters of the world's people live.
HENRY JACOBY, Mass. Institute of Technology: In the developing world,
you have both higher rates of population and higher rates of economic growth,
which means that they have a huge potential growth in greenhouse emissions, as
they develop their electric power systems, their transportation systems and the
like.
If you're living in a hot Chinese city, first you want a television set, and
then you want a fan, and then you want an air conditioner as you get more
wealthy. And you would want to do that. I would want to do that. And once
you have an air conditioner, then, and a television set, then you'd like to
have a car. And it's going to be very difficult for those countries to take a
path that is dramatically different from the one we took.
NARRATOR: In India, each person currently produces only one 40th as
much CO2 as an American. But India's population is so large and its growth so
rapid that it will soon surpass the U.S. in greenhouse emissions.
R. K. PACHAURI, Tata Energy Research Institute, Delhi: The country
today has about a billion people, and it's growing. In fact, the expectation
is, by about the middle of the next century, India will have the largest
population of any country in the world, larger than China.
We must remember that this is still a very, very poor country. You're talking
about people essentially earning a dollar a day. And given the fact that 70
percent of our population lives in rural areas, we have a long way to go.
NARRATOR: India has aspirations. Indians like Mr. Audyah want their
children to have the possibility to leave the villages. Over the next century,
India plans to transform itself from a largely rural agricultural society into
an industrial powerhouse. And the energy driving that transformation will come
largely from fossil fuels- in countries like India and China, mainly coal.
R. K. PACHAURI: Even to produce the basics of life, whether it's food
or steel or automobiles, whatever, you need large factories. And those large
factories need large power plants that would need large refineries and the
like. And you know, those are things that we can't get away from. They have
to grow if this country is to get rid of poverty.
NARRATOR: If rapidly growing developing countries like India simply
follow in the footsteps of the West, greenhouse emissions will soar as their
populations and energy consumption increase. To solve the global warming
problem, therefore, would clearly require the cooperation of the developing
world.
RON PRINN, Mass. Institute of Technology: What if the developing
countries did not take part, and we wanted to achieve this target of twice
pre-industrial levels? Then it would require the rich countries to have
negative emissions by about the year 2045 or 2050. In other words, they would
have to be pulling carbon dioxide out of the atmosphere to make up for the
growth in carbon dioxide emissions in the developing world.
NARRATOR: Back at Kyoto, confronting these issues polarized the
conference, pitching rich nations against poor. What was being negotiated was
nothing less than a greenhouse gas allowance for each country which they could
not exceed. But the developing nations argued that since they didn't create
the problem, they should be exempt.
R.K. PACHAURI: It's essential that the developed countries take the
first steps. They consume huge quantities of energy. They have the
technological and financial resources to start doing something about this
problem. This is the kind of leadership one expects the most powerful country
in the world to show.
HENRY JACOBY, Mass. Institute of Technology: They don't want to do
anything unless we go first. They didn't create the problem. They're poor,
we're rich. The gases that are up there are not their gases, they're our
gases. But it is also reasonable for us to say, "Hey, wait a minute. It
doesn't help for us to do this unless we have some kind of an agreement with
you that when you get to particular levels of income and ability, you will also
join in."
NARRATOR: The arguments went on for days. As time started running out,
it began to look like there would be no agreement. Still missing from the
negotiations was global warming's greatest champion, Vice President Gore.
RICHARD BERKE, "The New York Times": There was a real question of
whether Al Gore should go or not because there was the sense that this whole
thing could collapse. Some of his advisers were saying, "Don't go." Yet, on
the other hand, if he hadn't gone, it might have looked like he was scared or
shirking an issue that he's talked about throughout his career.
NARRATOR: At the last minute, Gore arrived to try and broker a deal.
After a day of intense negotiations, Gore managed to keep the Kyoto Protocol
from collapsing. And in an uncompromising speech, he reminded the delegates of
what he believed was at stake.
Vice Pres. AL GORE: The human consequences and the economic costs of
failing to act are unthinkable- more record floods and droughts, diseases and
pests spreading to new areas, crop failures and famines, melting glaciers and
stronger storms and rising seas.
Our first step should be to set realistic and achievable binding emissions
limits. For our part, the United States remains firmly committed to a strong
and binding target that will reduce our own emissions by nearly 30 percent from
what they would otherwise be, a commitment as strong or stronger than any we
have heard here from any country.
The imperative here is to do what we promise, rather than to promise what we
cannot do. For example, in my country, we remember-
NARRATOR: But in brokering the Kyoto treaty, Gore had agreed to let the
developing nations off the hook. They made no binding commitments to reduce
greenhouse gases. Most developed nations, however, committed to binding
cutbacks, with the U.S. agreeing to roll back greenhouse emissions to 7 percent
below what they were in 1990, about 20 percent below what they are today.
Reaction in the U.S. was swift
FRED PALMER, Western Fuels Association, Inc.: What the long-term goal
of the vice president of the United States is, is to ultimately eliminate all
fossil fuel use in the United States. President Clinton, in connection with
Kyoto said it was - his words - a "good first step." A first step to what? A
first step to eliminating fossil fuel utilization in the United States.
NARRATOR: As Gore left for home, he knew he faced a hard fight on
Capitol Hill. The Senate, who would have to ratify the controversial treaty,
were far from happy with the deal.
SEN. FRANK MURKOWSKI, (R) Alaska: My problem with Kyoto is there's no
net gain. In other words, if you allow the developing nations to have a free
ride, and if you buy their argument, well. they deserve a chance to catch up as
the industrialized nations have advanced, then when we're through, have we got
any significant net gain? Have we reduced emissions?
NARRATOR: Ironically, most climate scientists were also underwhelmed by
the Kyoto treaty.
TOM M.L. WIGLEY, Nat'l Center for Atmospheric Research: If everybody
were to come on board with the Kyoto Protocol, then that would slow down the
rate of climate change by a very, very small amount. As a best guess, we think
that the concentration of carbon dioxide in the year 2100 would be about 700
parts per million, which is roughly double what it is today.
If we enact and follow the Kyoto protocol, then we might reduce the buildup by
a few tens of parts per million carbon dioxide. In other words, instead of
doubling the amount of carbon dioxide, we might only increase it by 90
percent.
NARRATOR: Computer models show that the provisions of the Kyoto treaty
would not stop the rise in atmospheric concentrations. To do this means
eventually going way beyond Kyoto and cutting world fossil emissions by a half
or more.
How could this be done? Scientists and environmentalists could imagine a whole
range of potential solutions, from developing alternative energy sources to
expanding nuclear power to simply increasing energy efficiency.
STEPHEN H. SCHNEIDER, Stanford University: The first major thing to do
is to get efficiency improved. We are not anywhere near as efficient as we
could be. We don't all have the best motors, the best light bulbs and the most
efficient cars and industrial processes. We're not perfect. And therefore, if
climate policy forced us to be more efficient, we actually would be replacing
inefficient technologies with more efficient ones that would cost us less money
to buy them than the money we're saving in fuels.
NARRATOR: A lot of energy is simply wasted. If we made our energy go
further, we would need less and therefore emit less greenhouse gas.
JONATHAN G. KOOMEY, Lawrence Berkeley Nat'l Laboratory: An important
distinction to make in dealing with any of these issues is that there is energy
conservation, which is typically defined as deprivation- essentially putting on
a sweater, you know, dealing with discomfort in some way. And then there's
energy efficiency, using new technologies to do the same thing with less
energy.
NARRATOR: Many electronic devices leak energy. Televisions are a prime
example. When they operate, they draw about 100 watts of power. But even
after they are turned off, they may still draw energy.
JONATHAN G. KOOMEY: Some of my folks actually went to Circuit City and
measured all of the T.V.s there. And what they found was a huge range in the
stand-by power of these devices. And some of them, not just televisions, but
other kinds of appliances, were leaking as much as 20 to 25 watts. And you
found other televisions that were less than 2 watts, and there was no
difference in price for these devices. It was just that the manufacturers
hadn't really thought about it for a long time.
NARRATOR: But as even proponents of energy efficiency admit, human
behavior seems to be moving in the other direction. Americans are buying
larger homes and larger vehicles.
JOHN B. HEYWOOD, Sloan Automotive Laboratory, MIT: We are buying
larger, heavier vehicles, so the average weight and size has gone up. The
engines and transmissions we use have got a little more efficient, and the two
things are roughly canceling out. So the technology is getting more efficient,
but the miles per gallon aren't getting better because we're steadily buying
larger- more larger and heavier vehicles. So we have this choice. We could
all drive smaller vehicles, and they would use less fuel and put less CO2 into
the atmosphere. But that's not our current choice.
NARRATOR: But perhaps the biggest barrier to reducing greenhouse gases
is economic growth. American industry uses energy more efficiently than at any
time in history. The Andersen Window Company, which makes the top-of-the-line
energy-efficient window, is no exception. But ironically, because business is
booming, they use more energy than ever before. Because of the economic boom
of the 1990s, America enters the new millennium nearly 20 percent above its
Kyoto target.
RICHARD L. LAWSON, Pres /CEO, National Mining Assn: In the next 20
years, the nation's electricity requirements will be in creased by 60 percent.
We'll go from 3 trillion kilowatt hours presently to about 4.6 trillion
kilowatt hours in 2020.
INTERVIEWER: You're talking about America?
RICHARD L. LAWSON: That's the United States.
INTERVIEWER: Why does a rich country like America need to consume more
energy?
RICHARD L. LAWSON: It is a matter of all of the things that you and I
see around us. A computer on the Internet uses one kilowatt per hour in use.
And you think about the explosion of all of those computers not only in the
country but in modernized and developing countries around the world, you begin
to get an idea of what tomorrow looks like.
MARTY HOFFERT, New York University: The total energy consumption of all
of humankind at this point in time is about 10 terawatts. That's 10 trillion
watts. That's the rate at which primary energy is used. That's the rate at
which we are burning gas and oil and coal. That's 10 trillion watts. The
projections - the so-called "business as usual" projection - is that over the
next 100 years. the demand for energy will increase roughly by a factor of
4.
NARRATOR: These projections reveal just how stark the problem really
is. The world must somehow stabilize greenhouse gas emissions in the
atmosphere at the same time as it is planning to triple, even quadruple, its
energy use. By 2100, the world that these children's children will inhabit may
need 30 or 40 trillion watts. And to prevent massive greenhouse build-up, most
of this must be carbon-free.
MARTY HOFFERT: The magnitude of the job is massive. If you confront
the problem honestly - I mean, if you really look at the problem, and you say,
"What I want to do is I want to stabilize the amount of carbon dioxide in the
atmosphere at some level twice the pre-industrial level of CO2 - it's almost
impossible to do that unless there is a truly massive transition in the global
energy system away from fossil fuels. That is the bitter pill at the bottom of
all of these discussions.
NARRATOR: If America consumes ever larger amounts of energy, and if the
developing nations follow in its footsteps, then the world must sooner or later
confront an awesome challenge: to find a carbon-free replacement for fossil
fuels. Where will this energy come from? Some say the technology has already
been invented- renewable energy. Solar power, the energy of the wind, and
biomass, the growing of vegetable matter to use for fuel.
DAN LASHOF, Natural Resources Defense Council: I think it is very
credible that over a longer period of time, we can get the majority of our
electricity from new renewable energy sources.
NARRATOR: Others argue that what we need is an expansion of nuclear
energy, which also produces no greenhouse gases. But environmental groups do
not want carbon-free energy at that price.
ALEXANDRA McPHERSON, Greenpeace: Nuclear energy has no role in this
debate. We have no safe way of putting away radioactive waste. There are
cleaner alternatives, and Greenpeace firmly disagrees with the use of nuclear
power.
NARRATOR: Hydroelectric power has also recently come under attack.
ALEXANDRA McPHERSON: Large-scale hydropower has been very disruptive in
our rivers, specifically in the Pacific Northwest. We want to put an end to
hydropower, and cleaner energy solutions are there. Solar and wind power.
INTERVIEWER: So you don't want coal. You don't want nuclear. You
don't want hydro.
ALEXANDRA McPHERSON: Right.
INTERVIEWER: So what's left?
ALEXANDRA McPHERSON: Renewable energy technologies.
NARRATOR: In recent decades, great strides have been made to develop
sources like wind power. Buffalo Ridge in North Dakota is one of the windiest
locations in the United Sates. This wind farm has been sending electricity to
the Minneapolis grid for over two years now.
LARRY TAYLOR, President, NSP Electric: Southwestern Minnesota has some
of the best wind characteristics of any site in the United States. The problem
with wind is that the wind, on the average, blows 25 percent of the time. And
it blows the strongest in the spring and the fall, when our loads are the
lowest. At our peak times, in the peak summer, peak winter, it generally- a
lot of times it produces zero. We can't count on it being there. We have to
wait for the wind. If the wind's there, great. If it isn't, then we'll have
to open the throttles on something else.
DAN LASHOF, Natural Resources Defense Council: They're not going to all
be in one place. They're going to be spread around. So the wind may not blow
in North Dakota, but it'll blow in northern California. And that's when it
will start to become predictable, as the utilities get more experience with
it.
ALEXANDRA McPHERSON: The experts that we have been working with have
quoted that South Dakota, North Dakota and Texas have enough wind power
annually to meet the United States' electricity demands. Now, if the wind
starts blowing, then we would have, you know, back up resources, you know,
solar energy.
NARRATOR: In business for 15 years, Sunray, in southern California, is
one of the longest-running solar plants in the world. Its 30-acre field of
mirrors captures the energy of the sun and turns it into electricity without
emitting greenhouse gases. But it can only generate power when the sun
shines.
BRETT HOOVER, Sunray Energy, Inc.: The coal plant can generate year
'round, 24 hours a day. You know, here, you know,, we can just kind of run
when the sun's out, which is out quite a bit. You know, we get about 265 days
of sunshine here. But if you get any kind of high stratus clouds or anything
like that, you'll see your power just go right off the grid.
NARRATOR: When the sun's out, Sunray produces 30 megawatts of
electricity. While impressive, it can't yet compete with the coal plant next
door, which produces nearly 800 megawatts, 24 hours a day, 365 days a year for
a quarter of the cost.
Solar power has shown that it can play a valuable role in specific locations
where the sun is plentiful, especially in the developing world, in areas remote
from the electrical grid. The issue is whether renewables can be scaled up to
generate the massive amounts of energy that coal and nuclear do, whether they
can one day produce the trillions of watts the world's cities need, whether
they can ever replace fossil fuels.
MARTY HOFFERT, New York University: Most people want to turn on the
lights at night, and the sun isn't shining at night. Renewables tend to be
very episodic. That is, they're not always there. And the power density is
low. That is, the number of watts per square meter is pretty low.
NARRATOR: And this may be a crucial weakness. Because the energy
density of solar, wind and biomass is low, very large areas of land will be
needed to produce significant amounts of power.
MARTY HOFFERT: There's going to be a certain inevitable amount of land
use issues associated with renewable energy, in that you're going to need a lot
of area. If you wanted to supply 10 terrawatts of power and you wanted to do
it with biomass energy, you would need an area of the Earth equal approximately
10 percent of the Earth's surface, land surface area. And that's a huge amount
of land. That's all the land that's used in human agriculture right now.
Now, if you needed 30 terrawatts and you wanted to do it with biomass, you
would need three times as much. So you could sort of imagine a world where the
only things on the planet would be human beings and wheat, and we would eat the
wheat and we would use the wheat to make alcohol for our vehicles, but there
wouldn't be any other biological diversity because we would have appropriated
all of the land surfaces to do that. That's the kind of issue that you have to
deal with when you seriously talk about stabilizing CO2 in the atmosphere.
NARRATOR: Land use and siting issues have even tempered some
environmental groups' enthusiasm for wind energy. Recently, the National
Audubon Society opposed the expansion of wind farms in certain parts of
southern California because of threats to bird populations.
ALEXANDRA MCPHERSON: Greenpeace would not want to see, you know, every
bit of open space covered with windmills. That's not the issue, and that's not
the case that needs to be. The effects of building wind farms on our land,
compared to drilling in our oceans for oil or drilling- taking off mountain
tops for coal, is nothing compared to building wind farms or looking at solar
plants.
NARRATOR: The challenge of replacing fossil fuels in power stations is
hard enough, but roughly a third of fossil emissions come from our vehicles.
Because every gallon of gas releases 20 pounds of CO2, engineers have looked
for alternatives to petroleum. Some manufacturers imagine one day cars might
work like this model and run on hydrogen.
Instead of an internal combustion engine, this car uses a fuel cell, a kind of
battery, which combines hydrogen with oxygen to make electricity. The waste
product is simply water. Prototype vehicles already exist which can run on
hydrogen. The challenge to this vision of the future is where, exactly, will
we find the hydrogen.
JOHN B. HEYWOOD, Sloan Automotive Laboratory, MIT: Well, petroleum
comes out of the ground. Coal comes out of the ground. Natural gas comes out
of the ground. It's down in the ground, and we bring it out and use it.
There's no hydrogen stored in the ground. We have to make it.
NARRATOR: The good news is that you can extract hydrogen from natural
gas. The bad news is that CO2 is released in the process.
JOHN B. HEYWOOD: So if you take natural gas and you produce hydrogen,
you've taken the hydrogens from the natural gas, the hydrogen atoms, but the
carbon atom is going to come off as CO2.
NARRATOR: To mitigate the greenhouse gas problem, the hydrogen would
need to be made not from fossil fuels, but by splitting water molecules, using
carbon-free energy. And it's hard to see how renewable sources like solar and
wind can do this on the scale required, especially if they're expected to
generate the world's electricity at the same time.
RON PRINN, Mass. Institute of Technology: We need to think of the
renewables as nice augmentations. They're not going to fill the great demand.
The sensible thing to be doing now is to broaden all of the energy options that
we have. We need to look much more carefully at nuclear as a serious option
going into the future.
NARRATOR: While enthusiasts once dreamed nuclear energy would run the
world, no new plants have been built in the U.S. since the '70s. Plagued with
controversy, many of the nation's plants will be decommissioned in the next 20
years. But given the grim realities of greenhouse gas build-up, some climate
scientists are saying we should give nuclear another chance.
MICHAEL B. McELROY, Harvard University: I think that the mistake that
we have made is, again, we've made an irrational choice. The public has
decided that nuclear power is somehow or another dangerous, and more dangerous
compared to other forms of energy that we use. They are confused about the
differences between generating electricity with nuclear power, as compared to
building bombs and killing people with nuclear energy.
NARRATOR: But even assuming public fears could be erased, could a
greatly expanded nuclear program replace fossil fuels? Nuclear reactors use
uranium, a naturally occurring metal. How long would current reserves last if
they had to run the world at the current rate of 10 trillion watts?
MARTY HOFFERT, New York University: You only have about 10 years of
U235 power from all of the cost-effective uranium reserves. Even if you look
at reserves which are more expensive now, by this time, the nuclear power would
be getting considerably more expensive. You might have 30 or 40 years at 10
terrawatts. And what if we need 20 or 30 or 40 terrawatts for 100 years? Now
you're done.
NARRATOR: Conventional reactors cannot solve the problem. But there is
one possibility. Breeder reactors, which turn a more abundant form of uranium
into plutonium, can potentially extend nuclear's lifespan as a fuel source for
hundreds of years. But breeders are a very complex technology, and because
they produce plutonium, they raise serious issues about nuclear proliferation.
So today virtually no research is being done. [www.pbs.org: More on the
nuclear alternative]
HENRY JACOBY, Mass. Institute of Technology: A high priority, and one
that's now not being followed in the United States, is to find a socially
acceptable version of nuclear power. I think one of the great tragedies of the
current R&D- it's not a tragedy in that necessarily we are not building
more nuclear power because there is a lot of social reasons to worry about
nuclear power. The problem is we're not doing the research that would be
needed to search for a nuclear power option that would be socially
acceptable.
NARRATOR: Today there is no known energy technology capable of
delivering the amounts of carbon-free energy to stabilize greenhouse gases in
the atmosphere. The most commonly cited cures for global warming - efficiency
improvements, renewable energy and nuclear power - appear not to be up to the
challenge. But not everyone's demoralized.
MARTY HOFFERT: Try to imagine what the world was like in 1899 compared
to today and what the technologies were that were being envisioned by even
scientists and engineers and what actually happened. They missed the movies.
They missed airplanes. They missed automobiles. They certainly missed space
travel with nuclear power and radar and lasers. And so there's really an issue
of sort of timidity in the way that we've been projecting the technologies that
might mitigate the fossil fuel greenhouse effect.
NARRATOR: Hoffert argues that many of today's energy technologies -
like nuclear and solar - came out of government-funded military and space
research. So perhaps we need a Manhattan Project to find the technologies to
combat global warming, technologies which might capture the sun's energy in
space and beam it to Earth, technologies like nuclear fusion, offering
limitless carbon-free energy, even technologies which extract the carbon from
burning fossil fuels and sequester it back into the ground, and other
technologies which today are simply unimaginable. [www.pbs.org: Technologies
"beyond fossil fuels"]
MARTY HOFFERT: But we haven't been doing any serious research on this
problem. When I say "this problem," on the problem of how do we power the
world on a long-term basis with carbon-free energy?
NARRATOR: If the technological obstacles to combatting greenhouse gases
seem difficult, the political challenges might be even greater. Even before
the Kyoto conference started, the idea of U.S. cutbacks was in trouble in the
Senate.
SEN. CHARLES HAGEL, (R) Nebraska: It is the developing nations which
will be the biggest emitters of greenhouse gases during the next 25 years. It
is complete folly to exclude them from legally binding emission mandates. How
could any treaty aimed at reducing global emissions of greenhouse gases be at
all effective when it excludes these 130 nations?
NARRATOR: Remarkably, even liberal Senators concerned about global
warming had concluded that voting for Kyoto was political suicide.
SEN. RON WYDEN, (D) Oregon: The fact is, our country can control global
warming without causing an economic meltdown! Now, there are really three
approaches-
RICHARD BERKE, The New York Times: You can't underestimate that power
of interests on Capitol Hill that are opposed to this, between the business
interests and the labor interests and so forth. Even Republicans these days
are much more apt to call themselves green and to say they're fighting for
environmental issues, but they'll only go so far because you don't want to run
into danger with the business groups that are crucial to funding a lot of these
campaigns.
NARRATOR: In a rare display of unity, the Senate voted 95 to nothing
declaring their opposition to Kyoto.
SENATE PRESIDENT PRO TEM: The yeas are 95, and the nays are 0, and the
resolution is approved.
NARRATOR: Climate scientists, who had seen the treaty as a small first
step, were stunned.
MICHAEL B. McELROY, Harvard University: I can't imagine that 95 United
States senators believe that a rich country like the United States should take
no leadership role unless poor countries like India and China have taken equal
responsibility. I can't believe that 95 United States senators really believe
that. I mean, if you believe that, then you would have to say that we have
embarked on an incredibly selfish view of leadership.
NARRATOR: In the two years since Kyoto, nothing has happened. Facing
certain defeat, the White House has not even submitted the treaty to the Senate
for ratification.
FRED PALMER, Western Fuels Assn, Inc.: There is no chance of Kyoto
being ratified. We are not going to do it as a society. The notion of
reducing carbon dioxide emission levels in the United States 7 percent below
1990 levels by the year 2010 is a complete fantasy.
NARRATOR: While the Senate and the White House are stalemated, what do
the American people think - and what do they know - about global warming?
HANK C. JENKINS-SMITH, University of New Mexico: People in general tend
to know relatively little about this question. They know that auto emissions
or coal emissions generate greenhouse gas in fairly large percentages. But
there's an enormous amount of confusion, as well. Our own studies show that 50
percent of the populace, approximately, would attribute some global warming
cost to nuclear energy, for example, which is kind of a scary finding in this
particular context.
NARRATOR: Hank Jenkins-Smith is a political scientist who studies
public opinion on environmental issues.
HANK C. JENKINS-SMITH: If you ask people in general, "What do most
scientists believe?" majorities get it right. On the other hand, it doesn't
take much to upset it. One or two cogent arguments about the problems with the
science associated with climate change is enough to create substantial
skepticism.
FOCUS GROUP PARTICIPANT: There's so much range in the natural
fluctuations of all of the attributes of the Earth that I don't think they can
get a computer model to handle all of it.
FOCUS GROUP PARTICIPANT: You know, you can't predict what's going to
happen, you know, with the climate. Nobody can. That's my opinion. It's
like, they say one thing one day, and the next day something else happens.
FOCUS GROUP PARTICIPANT: The Iraq war, with the oil wells burning out
of control- they were telling us we're going to have a nuclear winter because
of all of this soot.
HANK C. JENKINS-SMITH: It appears that it's going to take some
convincing to get people to believe that this is a serious issue to which they
should devote some attention, let alone resources.
FOCUS GROUP PARTICIPANT: What, are you kidding?
FOCUS GROUP LEADER: Suppose that you were able to vote on a national
referendum to impose a tax on- just to keep it simple, let's put it on gasoline
- which would put money into a fund to study this question. Would any of you
vote for that kind of a referendum?
FOCUS GROUP PARTICIPANT: Absolutely not.
FOCUS GROUP LEADER: You would not vote for it at any price.
FOCUS GROUP PARTICIPANT: I would want to know why the average consumer
was being asked to pay for that. I mean, that would be my question. "Is this
the only place that this funding can come from?" It's a question we need to
answer, but do we need to pay for it?
FOCUS GROUP PARTICIPANT: For a mother with four children, 50 cents, you
know, or even anything on the dollar adds up really quickly.
FOCUS GROUP PARTICIPANT: And then you don't really know if it would get
used on that. I'm kind of skeptical as to where it is going to be used.
NARRATOR: The argument that the rich nations should take the first step
had not swayed the U.S. Senate. Does it resonate any better with the average
U.S. voter?
HANK C. JENKINS-SMITH, University of New Mexico: It doesn't seem to.
First off, remember that people can quickly retreat to the idea that, "Well, we
don't really know that it's that bad." And as long as they can retreat there,
then you don't have much moral point. You can make a moral point if they begin
to accept that these things are, in fact, having these potentially harmful
effects. And we're just not there yet.
NARRATOR: During the presidential primary campaign, some observers
began to wonder whether even global warming's most ardent advocate was backing
off from the issue. In his presidential announcement speech, for example, Gore
uttered only one brief sentence about global warming.
RICHARD BERKE, The New York Times: He hasn't really talked about it
hardly at all since Kyoto. There is some talk that his advisers fear it's a
no-win issue politically. This is the practical reality of running for
president. When you're a lone U.S. Senator writing a book, you can do more of
what you want and say what you want and say, "This is what I'm fighting for.
We got to have it. Win or loose, this is what I want."
But when you're in a position where you can make things happen, when the
spotlight is on you, when you want to be the next president of the United
States, you have to be a lot more careful.
NARRATOR: Then just last week, Gore suddenly seemed to openly embrace
global warming once again, reissuing his controversial 1992 book on the subject
and saying we must now take urgent action.
At Mauna Loa in Hawaii, scientists continue measuring the greenhouse gas
buildup in the atmosphere. Most climate scientists are now resigned that Kyoto
has failed. One thing, however, is certain: The amount of CO2 entering the
atmosphere will continue to rise. And in time, the impact on the climate will
become clear.
TOM M.L. WIGLEY, Nat'l Center for Atmospheric Research: What we are
afraid of is that if the planet warms too much, we're going into unknown
territory. If we were to warm the world by five degrees, then I strongly
believe that large parts of the Antarctic ice sheet would flow into the ocean
and melt and cause sea level to rise by many meters.
NARRATOR: Beyond sea level rise, many other serious effects may occur.
Increased frequency of intense storms, the spread of infectious diseases
throughout the world, major droughts, crop failures and famines, the
destruction of species and habitats- all these things are possible.
But it's equally likely that change will be more modest.
KEVIN E. TRENBERTH, Nat'l Center for Atmospheric Research: I certainly
think 50 years from now we will be seeing clear evidence of human climate
change. We will have a better knowledge of where it is in this range that
we've been talking about as to whether it is going to be huge or smaller.
Whether we will have clear evidence 20 years from now is not so clear to me. I
still think there will be substantial arguments. There will still be people
who will argue that this is natural variability, for one reason or another.
But gradually, with time, I think people will recognize that something weird is
going on with the weather, and maybe we should do something about it.
HENRY JACOBY, Mass. Institute of Technology: It is distant, and for
that reason difficult. But it's not so distant. If I have a grandchild today,
my grandchild born today will not be as old as I am until 2062. It's not that
far away, in terms of generations of people around. So you can care about this
issue because of people you know.
MARTY HOFFERT, New York University: We're in the fossil-fuel era of
human history. If humankind is going to have a future on this planet, it is
absolutely inevitable that we are going to have to find another energy source.
The thing that's happening to us now is that we have to make that decision in
the 21st century, whereas we may have been able to postpone it to the 22nd
century, if not for the greenhouse effect.
HENRY JACOBY: I think this is a very difficult problem, and I wouldn't
bet we can solve it. I think it is extremely, extremely difficult, but it's
worth our effort to really work hard to try to find a way to solve it because
the potential is that we're changing the face of the Earth for all future
generations.
A FRONTLINE/NOVA coproduction with
The Palfreman Film Group
copyright 2000
WGBH EDUCATIONAL FOUNDATION
ALL RIGHTS RESERVED
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