This is an edited transcript of a program broadcast on Channel
4 (UK) in 1990. It is interesting because it is one of the few
documentaries which questions the whole idea of the Greenhouse
Effect. This is unusual because, for some years now, it seems
to have been mostly reported as established, proven scientific
fact. It seems clear from the evidence gathered below that
is more a fashion than a fact!
Whilst it seems unwise to suggest something like the Greenhouse
Effect does not exist, or that manufacturing industry and the
human race's astonishing level of exploitation of natural resources
needs to be reduced, it must be pointed out that there are many
who have sought to use the Greenhouse Effect to present their
own agendas - both political and scientific.
It has all the hallmarks of a good disaster movie: an impending
crisis that threatens to engulf the world. From an almost benign
start a hardly perceptible change in global temperature the earth's
climate could suddenly topple into crisis, reducing large tracts
of land to desert, and wreaking havoc on our culture.
For the proponents of the greenhouse effect it heralds something
akin to an apocalypse: an earth scorched and burnt by the sun,
a climate in chaos. Nor is it a theory supported by a few cranks
it has been endorsed by the great and the good, by politicians
and academics alike. Nonetheless, there is mounting evidence that
it is not true.
Certainly, when it comes to the weather, our impression of what
is going on is often wrong:
An Earth Day conference was held at the University of Missouri
in the heart of the United States. One of the speakers at the
conference was Pat Michaels, a professor of environmental science
from the University of Virginia. He began his lecture by asking
the predominantly scientific audience how far the summer of1988
differed from the normal in Missouri.
PROF. PAT MICHAELS (Head of Department of Environmental Sciences,
University of Virginia, Charlottesville, USA) : The group estimate
is that Missouri averaged 2.2 degrees Fahrenheit above normal
for the calendar year 1988.
In fact it was below average.
PROF. PAT MICHAELS: You not only got the magnitude wrong, you
got the plus or minus sign wrong. I've given this talk about 120
times in places that were colder than normal in 1988 which was
much of the United States every crowd has estimated that it has
been warmer than normal. I believe you are all very intelligent
individuals that's why you are here so where did you get that
perception? I would like to know.
PROF. RICHARD LINDZEN (Professor of Dynamic Meteorology, Massachusetts
Institute of Technology, Boston, USA): The notion that a warming
is catastrophic is drilled into people, to the point where it
seems surprising that anyone would question it, and yet underlying
it is very little evidence at all. In fact, there is ample evidence
to the contrary.
NBC NEWS (23rd June 1988):
Some experts are saying now that the whole world is heating
up because of a global 'greenhouse effect' that is, heat caught
in the atmosphere by air pollution that prevents its escape.
NBC REPORTER: In Washington a senate committee heard some scientists
say the phenomenon called the greenhouse effect is here:
UNIDENTIFIED SCIENTIST. The problems, if not addressed, have
the potential for causing a form of chaos not greatly different
from that produced by global war.
ITN NEWS AT TEN (11th April 1989):
Information from satellites has convinced most scientists that
average temperatures will rise by two to five degrees Celsius
over the next one hundred years.
But is there any real evidence of a forthcoming disaster?
PROF. REGINALD NEWELL (Professor of Meteorology, MIT, Boston,
USA): No. I would not think there is any evidence for a catastrophic
change in our climate at the present time.
INTERVIEWER:No evidence at all?
PROF. REGINALD NEWELL There is no evidence at all.
The case for the greenhouse theory rests on four pillars. On the
one hand there's the factual evidence: firstly, that the Earth's
climate record shows temperature has increased and sea levels
have risen. Secondly, that carbon dioxide has been the primary
cause of these changes.
Then there is the third pillar which is not based on evidence
from the past or the present but on predictions of climate models
that the doubling of carbon dioxide will result in increases in
global temperature of between two and five degrees.
And finally, there is the underlying physics which it is widely
assumed proves that carbon dioxide is a greenhouse gas and that
further increases will result in increases in global temperature.
So let's start with pillar one and the facts about the Earth's
climate record.
It's far from easy to get an accurate picture of what's happening
to the world's weather. Our evidence is dependent on thousands
of individual measurements taken every hour of every day at weather
stations throughout the world. It may be Basildon or Phoenix,
Calcutta or Buenos Aires, but the techniques are the same. In
addition to temperature measurements, each weather station collects
data recording the hours of sunshine and the amount of rain. From
these measurements, sixty thousand every day, twenty-two million
a year, meteorologists try to discern what's happening to the
Earth's climate.
Analysis of temperature change over the last one hundred years
carried out by the team at East Anglia University in England has
played an important role in support of the greenhouse case.
PROF TOM WIGLEY (Head of Climatic Research Unit, University
of East Anglia, Norwich, UK): In the recent past the last century
or so global mean temperature has increased by about half a degree
Celsius. That doesn't 8Ound like a large amount, but it is a very
significant and important change.
But such claims are not universally accepted.
PROF. RICHARD LINDZEN: I think most scientists I know would
find it difficult to say anything about this record as it stands.
I'm reasonably confident that, given that record alone, few people
would plausibly say that this indicates that man has created warming.
There are a number problems with the data, the first of which
is that the weather stations are not evenly distributed around
the globe.
PROF. RICHARD LINDZEN: Land is only about 32 per cent of the
Earth's surface. If you want to take a global average, you're
already hoping that this 32 per cent will be representative of
the whole. For instance, St Helena Island represents one third
of the Atlantic Ocean, which is a bit questionable.
The weather stations may not be uniformly spread over the Earth
but in addition often tend to be situated in towns. In Phoenix,
for example, not only is the weather station in the middle of
the city, it is also next to the airport runways surrounded by
acres of tarmac. where overnight temperature can be ten degrees
hotter than the surrounding area because the asphalt retains heat.
Phoenix is like every other city: as it has grown, the temperatures
have gone up. Because many of the world's weather stations are
situated in towns, the temperature record is potentially threatened
by the urban heat island phenomenon.
DR ROBERT BALLING (Director of the Laboratory of Climatology,
Arizona State University, Phoenix, USA): We've been able to detect
heat islands in cities with populations as small as three hundred
people. As soon as you begin to replace natural vegetation with
concrete you create something of a distortion in the temperature
pattern.
It' s an effect that can add up to two or three degrees. If
we look at the issue of global warming and we ask, how much warming
do we think we should see in the future, it' s also something
in the region of one or two or three degrees.
Dr Balling has studied urban heat island effects in hundreds of
cities throughout the United States.
DR ROBERT BALLING: We have to be careful when we look at people
who say they have detected global warming because what they may
have detected is urban warming.
Professor Wigley defends his data and plays down the urban heat
island effect.
PROF.TOM WIGLEY: You can estimate what that residual effect
might be. We believe that it's quite small.
PROF. ROBERT BALLING: I agree it is a small effect in terms
of the total area of the globe that' s being affected by urbanisation.
The problem is that most of our measurements come from these areas.
INTERVIEWER:An awful lot of weather stations are in towns,
aren't they?
PROF. TOM WIGLEY: A number of them are. There are a number
of ways of accounting for the problem: the obvious way is to eliminate
those stations from the data set you use to calculate the large
area temperature values.
INTERVIEWER: But presumably there must be lots of towns where
you don't have data from around them, so it's very difficult to
tell whether there' s been an urban effect or not.
PROF. TOM WIGLEY: Oh yes. This is an area of on-going research
and still of some concern.
Dr Balling's results would seem to justify that concern.
DR ROBERT BALLING: We looked at a thousand stations in the
United States that came from very small towns averaging no more
than about 5,800 people. We looked at the temperature patterns
over this century and found that most of the United States has
cooled this century, not warmed.
Furthermore, new data from space has made the land record more
doubtful. Until recently we have had no alternative but to rely
on thermometers and weather balloons, but now, for the first time,
satellites are giving us another source of information.
Dr Spencer at the N ASA space centre has been able to analyse
the satellite data to produce snapshots of global temperature,
each one equivalent to tens of thousands of separate thermometer
readings taken by hand.
DR ROY SPENCER (Physicist, NASA Marshall Space Flight Centre,
University of Alabama, Huntsville): We've found that we can monitor
globally averaged atmosphere temperatures with a high level of
precision even on a monthly basis. We estimate the precision at
about one hundredth of a degree per month.
Unlike the thermometer data, the satellite information is evenly
spread and does not suffer from the urban heat island effect.
Over the last ten years, the thermometer record has shown an .
underlying upward trend but according to the satellite information
the Earth was rather warmer in the first half of the 1980s and
rather cooler in the second half.
DR ROY SPENCER: The trend of the thermometer data is only about
one to two tenths of a degree, which doesn't sound like much,
but it's enough to be significantly different from the satellite
indication of no trend.
Over the entire ten year period there was no net warming or cooling.
For the first time, satellites have given us an alternative to
the land-based data and they show no increase.
So there is a flaw in the first pillar that supports the greenhouse
theory - the urban heat island effect and the satellite information
point to question marks over the data on which claims of warming
have been based.
But even if we accept the thermometer data as accurate, whether
or not there has been a temperature increase depends on the time
scale you choose.
INTERVIEWER: Would you accept that over the past ten years
there has been no overall increase in global temperature?
PROF. TOM WIGLEY: No, I wouldn't accept that but that is a
question that may be irrelevant in the greenhouse context. The
greenhouse effect is a warming over a period of a century .
The warming Professor Wigley is referring to comes from a graph
of temperature over the last one hundred years which shows an
underlying increase of half a degree Celsius. The problem is that
the trend depends on the period you choose to examine.
PROF. RICHARD LINDZEN: If you started or ended it some place
else the trend changes. It' s clearly not a record you draw a
straight line through and say, 'This is warming'.
INTERVIEWER:
You mean if we took the last fifty years then it would tell a
different story.
PROFESSOR RICHARD LINDZEN: Yes, absolutely. In the last fifty
years it did nothing it went down and then up.
And if we choose the years from 1930 to 1970 the average temperature
actually falls fairly sharply.
We don't have the data to extend the graph back much beyond the
last one hundred years but there is evidence that there have been
periods in the past when it has been warmer than it is today.
Medieval records show that vines were grown throughout Britain,
and remains of a beetle, a species of neetle bug, have been found
in York, one thousand miles north of its current habitat in the
Mediterranean.
So, if we had thermometer records going back for a thousand fears
they could well show a fall in temperature.
Doubts over the data and problems with the time base have lead
Dr Idso, who has studied the effects of carbon dioxide on the
climate for the past twenty years, to be dismissive of claims
that the world is warming.
DR SHERWOOD IDSO (Scientist, United States Water Conservation
Laboratories, Phoenix, Arizona, USA): Some people claim that there
may have been a half a degree Celsius warming over the last one
hundred years. This is really tenuous.
If we look at the real world, let's say over the last 100-
150 years, you find no significant warming.
But perhaps, more than global temperature rise, it has been predictions
of increases in sea level that have encouraged impressions of
impending catastrophe.
Entire cultures are apparently faced with disaster.
CHANNEL 4 NEWS (4th April 1990):
(Scene of children playing on the beaches of a small island
in the Maldives). As the children play, year by year the waters
are rising around them. They will be adults by the time the Pacific
swamps the nine sandy stubs that are the Islands of Tuvalu. If
forecasts are correct the seas around here will rise by about
two feet over the next fifty years.
It is not only the media, the scientists themselves are not averse
to making the situation appear dramatic. Steve Schneider is one
of the United States' leading global warming theorists.
DR STEPHEN SCHNEIDER (Greenhouse theorist and modeller National
Centre for Atmospheric Research, Boulder, Colorado, USA): If the
sea level rises (the predictions range from a few tens of centimetres
to maybe a metre or so over the next one hundred years), that
by itself is not that serious, except to places that are low-lying
such as the Maldives, Venice and probably London. What really
is serious is of the warming of the ocean causes an increase in
the energy source for severe storms. Then you get a higher probability
if more intense hurricanes or other severe storms driven by ocean
evaporation.
PROF.TOM WIGLEY: That's particularly important in countries
like Bangladesh where there are tropical cyclones that, even today,
kill many thousands of people. In some parts of the world I think
there is every reason to believe that consequences would be severe.
But as with the temperature changes, the facts about sea level
rise tell a different story.
The Oceanographic Institute near Cape Cod, 250 miles north of
Manhattan, is one of the most influential organisations studying
the sea. For many years Dr Aubrey, who beads coastal research
at the Institute, bas travelled the globe investigating changes
in sea level.
INTERVIEWER: Can you tell whether the sea level bas gone up
or not over the last one hundred years?
DR DAVE AUBREY (Director of the Coastal Research Centre, Woods
Hole Oceanographic Institute, Massachusetts, USA) : No, you can't
say unambiguously say exactly bow much the ocean has risen over
the entire globe. Some tide gauge stations show sea level rising
over long periods of time, others show sea level falling.
The problem is that the land is also moving up and down - in
some places it subsides fairly fast. You are therefore measuring
sea level against another level which is also moving up and down
so you are left with a lot of uncertainty.
If you look at the British Isles you see the same thing in
a small portion: in the northern part of the British Isles the
sea level is falling, in the southern part the sea level is rising.
People have taken the average from different stations and different
periods and come up with different answers. In effect, you can
come up with any answer you want.
No useful conclusions about the future can be drawn from the
record.
We may not be able to predict what will happen in the future but
Aubrey bas no doubts about the evidence so far.
DR DAVE AUBREY: There is no evidence that sea level rise has
accelerated due to global warming.
We may not be able to confirm that the sea level is rising by
direct measurements, but in 1989 there appeared to be evidence
of sea ice melt when submarines passing under the pole reported
that the ice at specific points was less deep than it had been
ten years earlier. But Julian Paren at the British Antarctic Survey
is sceptical :
DR JULIAN PAREN (Scientist, British Antarctic Survey, Cambridge,
UK): Just two snapshots ten years apart, even if they did show
a thinning, would not be significant compared with long-term monitoring
of sea ice extent.
The submarine observations are contradicted by the only reliable
evidence, coming once again from satellites, which for the last
twelve years have given a daily picture of sea ice extent in the
Arctic and Antarctic
DR JULIAN PAREN: It shows no change. There have been changes
from year to year but taken as a whole you cannot say, statistically
speaking, that there has been any significant change in sea ice
concentration around the Antarctic.
The satellite data has only been with us since the late 1970s,
but recently analysis of the amount of salt in samples of ice
created from snow that has fallen over the last few hundred years,
taken from the edge of the Antarctic, has indicated that the present
levels of sea ice extent are far from exceptional.
DR JULIAN PAREN: The closer the open water comes to where you
take measurements, the more contaminated with sea s alt the ice
cores become.
It is quite clear that there have been periods of five to ten
years at a time when the sea ice level has been less than it is
today.
So, changes in the amount of sea ice do not support the idea that
the world is getting warmer.
It' s not surprising therefore that supporters of the greenhouse
effect back off from the actual data under scrutiny.
PROF. TOM WIGLEY: What we know about the greenhouse effect
is not just based on the data. The data is the ultimate way of
proving whether the models are right or wrong but because of the
natural variability of the system we cannot say yes or no.
DR STEPHEN SCHEINDER: Looking at every bump and wiggle of the
record is a waste of time it's like trying to figure out the probability
of a pair of dice by looking at the individual rolls. You've got
to look at averages. So, I don't set very much store by looking
at the direct evidence.
So, from the actual climate record of the earth, from the thermometer
measurements on land and changes in sea level and ice extent,
there is no convincing evidence of an increase in temperature
or of a rise in sea level.
The first pillar of the greenhouse theory proof of global warming
from the climate record turns out to have no substance.
Like the first pillar, the second pillar relies on our past evidence
of the climate, but this time to support the claim that carbon
dioxide causes an increase in temperature.
DR STEPHEN SCHEINDER: We know that when the earth Was colder,
20,000 years ago in the last ice age, there was 25 per cent less
carbon dioxide than during the present warm period, since the
industrial revolution. We also know there was 50 per cent less
methane. So we know cold times tend to be associated with less
greenhouse gases, warm times with more.
But that's only part of the story. Our knowledge of ice age temperature
and levels of carbon dioxide come once again from ice buried within
the Antarctic plateau.
Ice cores taken two thousand metres below the surface have enabled
us to look at the last 160,000 years.
There is no doubt from the record that for the last couple of
hundred thousand years temperature and carbon dioxide levels do
appear to follow each other. But it is far from clear that carbon
dioxide causes temperature to change.
DR JULIAN PAREN: We certainly know that the temperature falls
long before the carbon dioxide levels.
It's clear that declining temperature causes a decline in carbon
dioxide in the end. It's quite a straightforward effect.
So, if the record from the distant past tells us that, if anything,
it's temperature that causes carbon dioxide levels to change and
not the other way round, what does the recent past tell us?
One matter over which there is no dispute is that levels of carbon
dioxide in the atmosphere have increased substantially. But it
has not been a steady increase.
Carbon dioxide levels rose slowly from the middle of the last
century but it was only in the 1950s that levels started to increase
rapidly.
But, even if we accept the thermometer data, the temperature change
which is supposed to have been caused by carbon dioxide does not
coincide with the increases in carbon dioxide.
PROF. PAT MICHAELS: It's pretty apparent that the lion's share
of the warming occurred before the lion' s share of the trace
gases went in.
PROF. TOM WIGLEY: Yes that's a remarkable puzzle.
So how does he solve it?
PROF. TOM WIGLEY: In the first part of the century you see
a large natural warming. Natural variability has to go both ways,
so why is it strange that in the next forty years or so there
was a large natural cooling which was large enough to offset the
greenhouse effect?
Michaels has a more straightforward explanation:
PROF. PAT MICHAELS: Only so m any things can go against a simplistic
theory before you have to admit that the theory is simplistic
and needs revision.
So, not only does the climate record fail to prove that carbon
dioxide causes temperature change : if anything, it suggests the
reverse may be true. The second pillar supporting the greenhouse
theory turns out to be as insubstantial as the first.
The third pillar supporting the theory is constructed from the
climate models - perhaps more than anything else it is the predictions
of the models that doubling of carbon dioxide will lead to increases
in temperature of between three and five degrees by the end of
the next century that have sustained fears of an impending crisis.
But can we rely on these predictions?
Although superficially similar, the climate models are radically
different in character from the models used to provide daily weather
forecasts, which start from information about the current situation
and try to calculate what will be happening over the next few
hours and days. The complexity of the mathematics involved means
that the models cannot predict with any accuracy beyond five days.
Changes in climate take place over decades and centuries so these
weather forecasting models are of no use for estimating climate
change. So, instead of starting from current weather information,
the climate models try to simulate the entire climate of the Earth
from first principles.
The computer is given the amount of heat arriving from the sun,
the laws of physics which describe how heat radiates, and the
radiation properties of the atmosphere. With these starting points
the computer then calculates the temperature of the earth, the
wind speeds, the rainfall and so forth. The models then simulate
the Earth's climate over a number of years and produce an average
annual temperature cycle.
With a doubling of carbon dioxide large areas become hotter than
the current average.
Schneider's model, produced at the US National Centre for Atmospheric
Research, is one of about five influential current models of the
world's climate. But if we are to believe the predictions we must
first be convinced they can accurately simulate our current climate.
Dr Mitchell heads the team at the Met Office in Britain that has
developed another of the world' s major climate models.
DR JOHN MITCHELL (Modeller, Meteorological Office, Bracknell,
UK): We get a picture of not just the north-south distribution
of temperature but also of large-scale variation across the continents.
And this is very much as observed.
DR STEPHEN SCHNEIDER: We do very well: we let the sun go up
and it gets hotter; take the sun away and it gets colder. I remember
talking to a US Congressional hearing and one of the senators
said to me: 'you mean to tell me you've spent a billion dollars
of our money to tell us it gets hotter in summer and colder in
winter? ' My answer was: 'yes sir and we are very proud of that.'
Some scientists however are less impressed.
PROF. RICHARD LINDZEN: I don't think we can speak of these
models as being accurate at this point. They are experimental
tools. We're trying to forge these tools. To use them to forecast
delicate things like warming is calling for an accuracy these
models simply do not have.
PROF. REGINALD NEWELL: We certainly don't understand the models
well enough to take the predictions seriously.
One criticism of the models is that they fail to take account
of all the so-called feedback effects. Some of the most important
of these are related to clouds.
Professor Jonas is a world expert on how clouds affect climate.
His experiments are designed to find out how different types of
cloud reflect the sun's rays.
PROF.PETER JONAS (Head of Atmospheric Physics Group, UMIST,
Manchester, UK): The climate models are treating clouds in a very
simplistic manner and this makes it very difficult to include
the true magnitude of the feedback effects within those models.
As the temperature rises evaporation increases and more clouds
are created. But in turn the clouds then reflect the sun's radiation
away.
PROF. PETER JONAS: This causes less warming at the Earth's
surface so that the increase in temperature produces by carbon
dioxide is reduced by the presence of clouds.
These effects are not small.
PROF. PAT MICHAELS: The energy balance equation tells us that
everything else being equal, if you change the reflectivity of
the globe a mere two per cent or so, you compensate for the doubling
of carbon dioxide because you reflect away more solar radiation.
Slight changes in cloudiness can drastically influence how
the world responds to trace gases.
So, given the simplified character of the models, we should be
wise to treat their results cautiously.
PROF. TOMWIGLEY. They give roughly the right seasonal cycle of
temperature, they show it's warmer at the Equator than at the
Poles.
INTERVIEWER: These are pretty gross descriptions aren't they?
If they didn't show it WAS warmer at the Equator there' d be something
seriously the matter!
PROF. TOM WIGLEY. Yes, but it's more important that a model
used for climate studies predicts storm tracts over the North
Atlantic or shows you that the Sahara ought to be a desert.
But showing that the Sahara is a desert was precisely what the
Met Office model had failed to do according to its published findings.
If you look at the predictions for current rainfall they show
that as much rain falls on Central Sahara in summer as on Ireland
or Scotland.
DR JOHN MITCHELL: There's no doubt that on regional scales
of 2,000 kilometres or less, one cannot have a lot of confidence
in the model predictions.
Others go further.
DR SHERWOOD IDSO: I don't believe there is any good evidence
to lead us to believe what the models are telling us. Right now
they are predicting that for the carbon dioxide rise we have experienced
over the last century or so, there should have been a couple of
degrees Celsius warming, but there has been nothing like that.
There is the possibility of a half a degree warming but that maybe
due to other causes or it may not be a real warming . at all it
may Just be a figment. of the data due to problems such as the
urban heat island effect.
INTERVIEWER: Overall, are you confident that the models give
an outcome for global change that we can rely on?
DR JOHN MITCHELL: I am convinced that models are the best way
to determine what the outcome of the increases in trace gases
is.
INTERVIEWER: That's a different answer. The question is, can
we at the moment believe with any confidence in the predictions
they are making?
DR JOHN MITCHELL: Can you be more specific about what you mean
by predictions?
INTERVIEWER: The most obvious one is the effect of carbon dioxide
on temperature.
DR JOHN MITCHELL: I'm not sure how you quantify confidence.
PROF. PAT MICHAELS: We should caution here that it's not that
the modellers are incompetent bumbling people, they are limited
by the speed of light. That's why simplifications are made in
models.
INTERVIEWER: Why do you think people are taking the models
seriously?
PROF. REGINALD NEWELL: I don't know. It's very difficult for
me to understand how you could possibly take the aggregate of
these models seriously. You look at the differences of predictions
for one region at one time.
The third pillar supporting the greenhouse theory turns out to
be as flimsy as the first two.
So there is only one remaining support for the theory: the underlying
physics.
DR STEPHEN SCHNEIDER: The reason I believe there is a high
probability of unprecedented change in the next century is not
based on the performance of the planet in the last one hundred
years - there are just too many unknown and unknowable factors.
It's based on the greenhouse physics.
The greenhouse physics is supposed to show that carbon dioxide
is a greenhouse gas : that it absorbs radiation reflected from
the Earth's surface and emits that radiation again, causing an
increase in radiation, or heat flux, arriving on the surface on
the Earth, and a w arming of the planet.
DR JOHN HOUGHTON (Chief Executive of The Meteorological Office,
Bracknell, UK): We know how much greenhouse gas has gone into
the atmosphere : we know how much more methane there has been
over the last one hundred years, we know about CFCs (they're greenhouse
gases too). So, we know there will be some warming.
But the assumption that the basic physics necessarily implies
a warming is not accepted by some atmospheric physicists.
INTERVIEWER: There are a lot of scientists around, not only
members of the public, who are categorically saying that if you
increase carbon dioxide in the atmosphere you get heating.
PROF. REGINALD NEWELL: I'm saying that is not at all evident.
Carbon dioxide is not the only greenhouse gas, nor the most important.
Water vapour and ozone are the primary greenhouse gases. A number
of other trace gases such as methane play a minor role. These
gases do not simply absorb radiation, they also emit it - in fact
they emit as much as they absorb. Furthermore, the way they absorb
and emit radiation changes throughout the atmosphere. The radiative
process is therefore highly complex and the effect of any one
gas is not the same throughout the atmosphere and is linked to
all the other gases.
PROF. REGINALD NEWELL: Additions of carbon dioxide into the
atmosphere will certainly cause an increase in the downward flux
of energy at the surface but that will not necessarily change
the temperature of the lower layers of the atmosphere. I think
it will cause more water to evaporate, which will have a lot of
ramifications, one of which will be the radiative effects. These
will tend to produce more cooling, and also more clouds which
will reflect the solar radiation. So it's not at all obvious that
increasing the carbon dioxide in the system will make the temperature
rise.
Professor Newell is not alone in this view. In a recent paper
on the effects of carbon dioxide, Professor Ellsaesser of the
Lawrence Livermore Laboratories, a major US research establishment
in California, concluded that a doubling of carbon dioxide would
have little or no effect on the temperature at the surface and,
if anything, might cause the surface to cool'.
The radiation effects of the greenhouse gases are further complicated
by convection currents which carry warm air at the surface to
higher altitudes.
PROF .RICHARD LINDZEN: If you put greenhouse gases near the
surface and convection currents short circuit them, they won't
contribute to warming. If you put a lot in at the surface and
take a little away near the top where the heat is deposited by
convection, that could lead to cooling, even if you had a net
increase in the amount of greenhouse gas. There is no simple uniform
relation between the amount of greenhouse gas in the atmosphere
and the temperature at the surface. We just don't understand enough
about the behaviour of the atmosphere to predict the effect of
a change in the level of carbon dioxide with any certainty.
Even the final pillar supporting the greenhouse theory, the underlying
physics, turns out to be as insubstantial as the rest.
Although there is no convincing evidence that increases in carbon
dioxide are bad for us, it's still easy to think of it as a pollutant.
But carbon dioxide is the equivalent of oxygen for plants : the
essential life-giving gas. It may well be that the increase in
carbon dioxide levels turns out to be a good thing.
DR SHERWOOD IDSO: The vegetation of this planet developed and
acquired its basic characteristics in an atmosphere that had much
more carbon dioxide than at present. Logic will therefore tell
you that if you have more carbon dioxide in the atmosphere, plants
will do better and this is exactly true.
For the past three years Dr Idso has been growing sour orange
trees in enclosures containing double the amount of carbon dioxide
to normal. The carbon dioxide enriched air is continuously pumped
into the chambers and escapes at the top.
At the same time identical trees are kept in exactly the same
conditions but are fed normal air. These enriched trees have 180
per cent more volume, have more leaves, more primary branches,
more higher-order branches, more blossoms.
DR SHERWOOD IDSO : An interesting question is how much carbon
dioxide we can possibly put into the atmosphere if we bum all
the fossil fuels the crust of the earth. It has been estimated
that the maximum would be ten times the present level, which would
do no harm to animal life and would still be beneficial to plant
life.
It's very likely we will need the added benefit of carbon dioxide
enrichment to feed future the generations.
If there is concrete evidence of the benefits of carbon dioxide,
and the detrimental effects are at the very least questionable,
how is it that we have been led to take talk of catastrophe seriously?
After all, it was only some fifteen years ago when a rather different
global climate catastrophe was in vogue.
"THE WEATHER MACHINE" (BBC 1, November 1974):
There's the ever-present threat of a big freeze. Will a new
ice age claim our lands and bury our northern cities? It's buried
Manhattan Island before when great glaciers half a mile thick
filled the valley of New York's Hudson River.
INTERVIEWER: You do accept that ten to fifteen years ago people
were talking about global cooling, not warming?
DR STEPHEN SCHNEIDER: Not everybody - I was one who was not
sure.
INTERVIEWER: You say you didn't believe in global cooling but
in your first book you said, 'I have cited many examples of recent
climatic variability and repeated the warnings of several well-known
climatologists that a cooling trend has set in, perhaps one akin
to the Little Ice Age. Well, that was just fourteen years ago.
DR STEPHEN SCHNEIDER: I said that because at the time it was
true. But you've got to be honest, you've got to tell things the
way they are. I don't mind people quoting what I said in the 1970s.
INTERVIEWER: Doesn't all of that add up to saying that you're
asking governments to spend billions of dollars on a view which
is different from one you held a decade ago?
DR STEPHEN SCHNEIDER: I don't see any problem in saying that
people learn. I'm not embarrassed about a view I held a decade
ago.
PROF. PAT MICHAELS: You should remember, when I was going to
graduate school, it was gospel that the ice age was about to start.
I had trouble warming up to that one too. This is not the first
climatic apocalypse, but it' s certainly the loudest.
There may be many reasons why we might want to believe in a apocalypse
but for the scientists involved it's very straightforward.
DR ROY SPENCER: It's easier to get funding if you can show
some evidence for impending climate disasters. In the late 1970s
it was the coming ice age and now it's the coming global warming.
Who knows what it will be ten years from now. Sure, science benefits
from scary scenarios.
DR SHERWOOD IDSO: A lot of people are getting very famous and
very well funded as a result of promoting the disastrous scenario
of greenhouse warming.
PROF. REGINALD NEWELL: My suspicion is that if you have a crisis
like this it' s easier to gain funds for the profession as a whole.
PROF. TOMWIGLEY: I don't think funding directly influences
the nature of the research or the approach. .
INTERVIEWER: But indirectly?
PROF.TOMWIGLEY. Using my organisation as an example, we have
only one permanently-funded university scientist that's me. I
have a dozen research workers with Ph.D.s who are working in the
climatic research unit and they are all funded on so-called soft
money. Their existence requires me, or us jointly, to get external
support.
Funding may have encouraged support of the greenhouse theory,
but if you oppose the theory, life can get difficult.
PROF. REGINALD NEWELL: I was warned when I wrote my first paper
which discussed the difference between the climate models and
some figures I was looking at for the Tropics that it would be
very difficult and my funding would probably be cut. In fact it
has been cut.
INTERVIEWER: Did you believe that at the time?
PROF. REGINALD NEWELL: No, I thought that the system was so
straightforward and honest - that bringing in a new perspective
to the whole thing which I thought I did in 1979 would be considered
to be a positive thing: people could hear both sides of the argument
and then have a debate.
INTERVIEWER: Perhaps the greenhouse theory has been successful
in terms of raising funds : by saying there' s a crisis around
the corner, people are talking about putting in more funds.
PROF. REGINALD NEWELL: Perhaps it has worked; perhaps I was
wrong but I think it's going to backfire.
DR ROY SPENCER: Richard Lindzen has recently said that this
whole area has become a new McCarthyism. If you don't jump on
the environmental bandwagon to stop the inevitable warming of
the Earth, then you will be ostracised from the scientific community
and from everybody else's community , because it's not fashionable
to disagree with the environmentalists these days.
PROF. PAT MICHAELS : People who have a point of view which
may not be politically acceptable are going to have problems.
That's not surprising. I have had experiences with editors of
more than one journal who have said that my papers have been rejected
because they are held to a higher standard of review than others.
I believe this is because what they say is not popular. That's
OK: I'm a big boy. I know I would have been more successful if
I had said the world is coming to an end, but I can't bring myself
to do that.
Of course it's not only been the scientists. The media also benefits
from a good disaster story.
'THE BIG HEAT' (Panorama, May 1990):
Storms, cyclones, drought, high winds and floods: a foretaste
of global warming, a change in global climate caused by man's
pollution of the planet.
To say that the climate is OK does not usually make the headlines.
And the best prophets of doom are the ones filmed most. (Shot
of Stephen Schneider being interviewed in front of the cameras).
DR STEPHEN SCHNEIDER: The rate of change is so fast that I
don't hesitate to call it potentially catastrophic for ecosystems.
PROF RICHARD LINDZEN: There. are statements made of such overt
unrealism that I feel embarrassed. I feel it discredits my science.
I think problems will arise when one will need to depend On scientific
judgement and by ruining our credibility now You leave society
with a resource of some importance diminished.
DR STEPHEN SCHNEIDER: Of course you always tell the truth,
but how many people get more than a few seconds in the evening
news? So you use information selectively.
And if the scientists and the media have connived to make a good
story, the politicians have not been slow to see the advantages.
MARGARET THATCHER (BBC News, 25th May 1990):
We would be taking a great risk with future generations if,
having received this early warning, we did nothing about it Or
took the attitude, Well, it will see me out.'
INTERVIEWER: Why do you think it is that politicians, and indeed
Congress, have been convinced that there has been global warming?
PROF.PATMICHAELS: I don't know that they have been convinced,
but their business is to be responsive to their constituents and
their constituents are convinced. It would certainly not be in
their best political interests not to act convinced, would it?
So, the people want to believe this and the politicians can't
say to their constituents, {You are stupid,' can they?
It may not quite add up to a conspiracy, but certainly a coalition
of interests has promoted the greenhouse theory : scientists have
needed funds, the media a story, and governments a worthy cause.
And beyond that, is it the millennium that encourages notions
of an apocalypse, or simply that in a world without belief we
need a catastrophe to give us something to believe in; where for
once, in a battle between nature and humankind, we can line up
on the side of good against the forces of evil.
PROF. PAT MICHAELS: There's a lot of blood in this battle;
people hate each other about this issue. Haven't you noticed that?
Have you ever seen a nastier scientific issue? I guess it' s because
people passionately feel that it' s a battle between good and
evil.
If the consequences of the greenhouse theory did not extend beyond
a moral crusade it could be left to those of a religious turn.
of mind. But it cannot be so lightly ignored.
PROF. PAT MICHAELS: Would you walk down the road towards a policy which people have rightly said requires an economic restructuring of the world, knowing that the world was doing the opposite to what the basis for that policy said?