| Since antiquity, people had speculated about the consequences of
cutting down forests or draining swamps to create farmland. Renaissance
and later scholars who pored over ancient manuscripts saw that deforestation,
irrigation, and grazing had altered the lands around the Mediterranean.
Surely these human interventions had affected the local weather? The
scholars thought it plausible, and common people adopted the notion.(1)
|| - LINKS
| Human and Planetary Forces
| The most striking change, obvious within a single lifetime, was
the conversion of Eastern North America from forest to croplands.
By the early 19th century many believed the transformation was altering
the region's climate probably for the better. When sodbusters
took over the Great Plains they were told that "rain follows the plough."
| Not everyone agreed, and the topic could always raise a lively
discussion. Some experts reported that where forests were cut down,
the flow of water in rivers did not rise but actually fell. Deforestation
not only caused rainwater to run off rapidly in useless floods, they
said, but reduced rainfall itself. European professors, alert to any
proof that their nations were wiser than others, explained that the
Orientals of the Ancient Near East had heedlessly converted their
once lush lands into impoverished deserts.
| In the latter 19th century, official commissions in several European
countries studied the question of whether reforestation should be
encouraged probably the first government concern for human
effects on climate, a century ahead of its time. These inquiries could
not lead to action, when scientists disagreed on whether a given change
in land use brought more rain or less. "It seems almost a psychological
puzzle," an expert complained in 1890, "that for one and the same
country serious scientists have at every step insisted on climate
changes which are mutually exclusive.... We have to admit that even
today we are still far from a definite answer..."(2) The farmers and other concerned people who paid attention
to these debates could readily see that science had nothing reliable
to say about climate change.
| Meanwhile, national weather agencies had begun
to compile masses of reliable observations of temperature, rainfall,
and the like. When the figures were analyzed they showed many rises
and dips, but no steady long-term change. Toward the end of the 19th
century, scientific opinion turned decisively against the belief that
human actions could affect local climates.
| Whatever the local effects, few had imagined humans could affect
the climate of the planet as a whole. Today, in the 21st century,
"wilderness" is something we imagine as a preserve of trees and animals
surrounded by the fuming machinery of civilization. Earlier people
saw the world the other way around, themselves living in a village
surrounded by endless expanses of wild nature. At the start of the
20th century, civilization still seemed like an enclave, a patch of
hopeful technology amid wastelands only partly explored. Barely a
billion people populated the world, mostly ignorant peasants living
like medieval serfs. If people chopped down stands of trees and plowed
up a prairie for farming, those were local improvements, which
nobody imagined could affect the planet as a whole. The atmosphere
in particular was controlled by geochemical forces that were surely
indifferent to any human activity
| These planetary forces,
however, could bring devastating changes. Everyone had seen illustrations
of the old ice ages, with cavemen hunting wooly mammoths through the
snow. Looking farther back, scientists described a tropical age of
dinosaurs basking in balmy swamps, even in regions that were now arctic.
A popular theory held that the dinosaurs had perished because gradually,
over millions of years, the world had become too cold for them. Or
geological forces, such as a long series of volcanic eruptions, might
impose a world desert like the one where the last dinosaurs lay down
to die in the 1940 Disney movie Fantasia. Even Bible fundamentalists
accepted climate change, arguing that our sorrowful world of storms
and snows had replaced an originally temperate, Edenic climate. Consider,
they said, how mammoths had been found frozen intact with grass in
their stomachs, apparently felled when the climate changed in a single
night.(3*) Turning to historical times, scientists
and popular writers proposed theories about how gradual natural shifts
between rainy times and dry times had caused the rise or fall of ancient
Full discussion in
| All these theories were chiefly a matter for
geologists and historians of antiquity. In the foreseeable future
of human society, the next few hundred years, people expected the
climate to stay near its "normal" state the state congenial
to human civilization. Of course there could be deviations from the
normal. From Noah's Flood to the Dust Bowl drought of the 1930s, ideas
about climate included a dose of catastrophe. But a catastrophe was
by definition transient, passing away after a few years. As for long-term
climate shifts of the sort that some believed had laid low Near Eastern
civilizations, if such shifts existed at all they had been too gradual
to be noticeable except over several generations. Anyway the climate
changes that people thought about affected only this or that local
region. People scarcely imagined that their own doings, so puny among
the vast natural powers, could upset the "balance of nature" that
governed the planet as a whole.
| This view of Nature as supra human
and inherently stable lay deep in most human cultures. In Western
thinking this belief was traditionally tied up with religious faith:
the God-given order of the universe would stand in flawless and imperturbable
harmony until the Last Days. Indeed clerics might point to examples
of natural regulatory mechanisms as proofs of Divine Providence. Darwin's
theory of evolution shook this faith only a little. Even those who
acknowledged evolution believed that changes in the planet’s
inventory of living creatures must be so gradual and progressive that
harmony would prevail at every stage.
| Scientists too believed in the balance of
nature. By the end of the 19th century, geologists had become convinced
that nature operates through steady and uniform processes. They held
that view all the more strongly because of vehement opposition from
people who tried to explain geological features by abrupt, supernatural
catastrophes like Noah's Flood. Modern geology declared that many
millions of years of Earth's geological history showed that biological
and geophysical systems had maintained an overall equilibrium.
| This was a serious obstacle for G.S. Callendar
when, in 1938, he presented sketchy evidence that humanity's use of
fossil fuels could be causing global warming through the greenhouse
effect of carbon dioxide gas (CO2). Callendar
recalled how nearly every expert on climate rejected his arguments.
"The idea that man's actions could influence so vast a complex," he
wrote, "is very repugnant to some."(4) What scientists did find plausible were simple hand-waving
arguments that seemed to prove that emissions of CO2,
or any other human intervention, could not possibly change global
climate. Since this was the answer they expected, few tried to probe
deeper. When journalists reported what scientists said, the confidence
in natural self-regulation not only echoed but reinforced the public's
| Human industry was in fact too small in the
first half of the 20th century to noticeably affect the climate. Hardly
anyone expected much greater impact during the next century or two.
People did not grasp the prodigious fact that both population and
industrialization were exploding in a pattern of exponential growth.
Between the start of the 20th century and its end the world's population
would quadruple, and the use of energy by an average person would
quadruple, making a 16-fold increase in the rate of emission of CO2. Yet the First World War and Great Depression led industrialized
nations to worry about a possible decline in their populations.
Their industries seemed to be plodding ahead in linear growth, that
is, expanding no faster in the current decade than last decade. As
for "backward" regions like China or Brazil, industrialization scarcely
entered anyone's calculations except as a possibility for the remote
| Even if human activity could have global effects some day, was
that a problem? Nearly everyone saw technology as benign. People believed
that in the centuries to come, scientists and engineers would turn
deserts into gardens, poverty and ignorance would decline, and everyone
would become steadily happier. Typical was the attitude of Svante
Arrhenius, the first scientist to suggest that sometime (thousands
of years from now) we might have produced enough CO2
by burning fossil fuels to warm the atmosphere. In a popularizing
book of 1908 he wrote, "we may hope to enjoy ages with more equable
and better climates, especially as regards the colder regions of the
Earth, ages when the Earth will bring forth much more abundant crops
than at present, for the benefit of rapidly propagating mankind."(6) Callendar, when he presented his evidence
that greenhouse effect warming was already underway, likewise looked
forward to it. Not only would the warmth and extra carbon help crops
to grow more abundantly, he said, but "the return of the deadly glaciers
[of the ice ages] should be delayed indefinitely."(7) A Swedish meteorologist and friend of
Arrhenius, Nils Ekholm, was still more sanguine. Writing in 1901 in
the heyday of optimism for technology and progress, he exclaimed that
"it seems possible that Man will be able efficaciously to regulate
the future climate of the Earth." Man could release natural gas, Ekholm
explained, or if desired absorb CO2 by "ruling
the growth of plants according to his wants and purposes."(8)
|The public heard little of this. Only an educated minority of a
few millions were attentive to science at all. These people might
notice a rare mention of greenhouse warming buried as a paragraph
or two in some popularizing article about climate. To them, as to
most scientists, that was just one of the many barely plausible stories
about a distant, science fiction future, a subject for crackpot speculations
and outright fantasy. One example was a popular Japanese children's
tale of 1932 in which the hero set off a volcanic eruption to warm
the Earth with carbon dioxide emissions.(8a) The vast majority of the world’s people, even educated
people, suspected that rain-makers might manipulate local weather,
but never imagined that we had already begun to alter the entire planet’s
| From Grandfathers' Tales to Nuclear
TOP OF PAGE
| The first hint of actual global warming came
from public memory. In the 1930s, grandfathers were heard to say that
when it came to weather, the younger generation had it easy. Gone
were the early frosts and daunting blizzards of their own youth. The
popular press began to publish articles, pointing out that in fact
rivers were not freezing over as formerly and so forth. Science reporters
found experts who confirmed that crops and codfish were now harvested
in northern zones where they had not been seen for centuries. When
meteorologists scrutinized the records, they confirmed that a warming
trend was underway. As Time magazine put it in 1939, "gaffers
who claim that winters were harder when they were boys are quite right...
weather men have no doubt that the world at least for the time being
is growing warmer."(9)
| Nobody was much concerned. The meteorologists
thought it likely that temperatures rose and fell modestly in centuries-long
cycles. The grander and slower cycle of ice ages might also be on
a warming upswing ("But you can work up a cycle for anything," as
one expert told a reporter).(10)
If the 20th century happened to be a time of warming, so much the
better. A typical popular article of 1950 promised that "vast new
food-producing areas will be put under cultivation." It was reminiscent
of old familiar theories about how ancient civilizations had risen
and fallen in obedience to gradual shifts of rainfall and other regional
| Some reports were more sensational. If warming
continued, new deserts might appear, and the oceans might rise to
flood coastal cities "another deluge, such as the catastrophe
recorded in the Bible."(11) People recalled also the old Euro-centric belief, repeated
by some scientists, that heat is enervating. Many Europeans thought
it was a scientific fact that the temperate zones inhabited by the
"Caucasian race" were naturally superior for the spread of civilization.
Life magazine warned that a warmed-up climate might make
everyone as lazy as the natives of the tropics were supposed to be.
And then there was the fact that sex crimes rose at the start of summer!(12)
| As prediction, all this was plainly nothing but colorful speculation
about the remote future. Time magazine explained that
"Meteorologists do not know whether the present warm trend is likely
to last 20 years or 20,000 years." Many professional meteorologists
doubted that there was in fact any world-wide warming trend. They
saw only normal, temporary, regional fluctuations. In 1952 the New
York Times remarked that thirty years from now, people might
look back fondly on the mild winters of the 1950s.(13)
| The future was all the
more obscure since the cause of the supposed warming trend was unknown.
Some articles mentioned the possibility of a CO2
greenhouse effect, but they only listed it along with more widely
accepted theories of climate change erratic volcanoes, solar
variations, and so forth.(14)
At times even good journalists would also report some half-baked theory
of climate change advocated by someone with a Ph.D. Further speculations
came from amateur meteorologists, who were not yet easy to distinguish
from professionals. As one writer put it, "Everyone has his own theory
and each sounds good until the next lad comes along
with his theory and knocks the others into smithereens."(15) In short, the science-attentive public was well informed
that climate theory was in a dismal state. That scarcely seemed to
matter, if nothing we could do would change the climate anyway. It
took barely a decade for public attitudes to reverse. The reversal
was not because of any changes in what scientists knew about global
warming. The public's rising concern for human impacts came from far
more visible connections between technology and the atmosphere.
| One of these was a growing
awareness of the dangers of atmospheric pollution. In the 1930s, citizens
had been happy to see smoke rising from factories: dirty skies meant
jobs. But in the 1950s, as the economy soared and life expectancy
lengthened, in industrialized countries a historic shift began from
worries about poverty to worries about chronic health conditions.
Doctors were learning that air pollution was mortally dangerous for
some people. Meanwhile, on top of smoke from coal-burning factories
came exhaust from the rapidly proliferating automobiles. A "killer
smog" that smothered London in 1953 demonstrated that the stuff we
put into the air could actually slay several thousand people in a
few days. Effects on health also became evident in Los Angeles during
the 1950s. Many Americans did not take the problem seriously, however,
until a deadly smog assaulted New York City in 1966. Events in New
York always had a disproportionate influence on the media headquartered
| Another thing that drew the public's attention
to the air was exciting news about manipulating weather. During the
1950s, the press prominently reported attempts to make rain by "seeding"
clouds with silver iodide smoke. Scientists openly speculated about
other technical tricks, such as spreading a cloud of particles at
a selected level in the atmosphere to interfere with solar radiation.
Journalists and science-fiction authors explained that in a not distant
future we might alter climates over entire nations to their benefit.
Or perhaps to their harm. Scientists publicly warned about the approach
of "climatological warfare." Might the Russians someday inflict deadly
blizzards on the United States in a truly Cold War?
| It had become plausible that by putting materials into the air,
humans could alter climate on the largest scale. The frequent and
colorful press coverage of cloud seeding and so forth helped convince
the public that it was possible for humanity to alter the climate.
Even decades later, when poll-takers asked people about causes of
climate change, many thought first not of industrial emissions but
of technical feats such as spaceship launches and nuclear explosions.(17)
| The astonishing advent of nuclear energy was central to the change
in thinking. Suddenly nothing seemed beyond human power. To many people
the news of a limitless energy source was hopeful, even utopian. For
example, experts speculated that we would soon be able to use salvoes
of atomic bombs to control weather patterns, bringing rain exactly
where it was needed. At the same time, scientists warned that a nuclear
war could destroy civilization. Science-fiction stories, like the
widely seen 1959 movie On the Beach, pictured the extinction
of all life by radioactive fallout, carried around the world on the
winds after a nuclear war. Many among the public suspected that dust
from atomic bomb tests was already affecting the weather. From about
1953 until open-air testing ceased in the mid 1960s, as opponents
of nuclear armaments pointed with horror to the invisible dangers
of fallout, some people blamed the faraway tests for almost any unseasonable
heat or cold, drought or flood. In a magazine article laying out the
evidence that global temperatures were rising, the authors remarked
that "Large numbers of people wonder whether the atomic bomb is responsible
for it all."(18)
| The new threats awoke images and feelings that most people had
scarcely experienced outside their dreams and nightmares. Humans were
introducing unnatural technologies, meddling with the very winds and
rain, spreading pollution everywhere. Would we provoke retribution?
Would "Mother Nature" pay us back for our attacks upon "her"? At the
deepest level, horror movies about radioactive monsters hinted at
infantile fantasies of filth and incest, attack and punishment.(19) Such veiled anxieties were not detectable
in the sober discussions of subjects like climate change. But the
public did develop a vague feeling that natural disasters followed
not only scientific law but moral law a punishment for unhallowed
| Of course, this was nothing new. Many tribal peoples attributed
climate disasters, such as an unusually severe winter, to human misdeeds.
Somebody's "polluting" transgression of rules was to blame. The community
was being punished because someone had carelessly bungled a ceremony,
violated an incest taboo, or the like. Just so was the Flood of Noah
called down upon humanity by our sins. It was not only primitive tribes,
but sophisticated civilizations too, that saw the natural order as
so intrinsically benign and harmonious that any severe disruption
must be due to human misdeeds. Chinese dynasties were shaken when
people held the corruption of the Emperor and his mandarins to blame
for devastating floods; European communities until quite recently
declared days of public penance as an answer to droughts.
| During the 1950s, human-caused disruptions of nature all the way
up to global destruction took on a veneer of scientific plausibility.
As the nuclear arsenals grew, Bible fundamentalists got a wider hearing
than ever for their prophecies of rivers of blood, rains of fire,
and the like. Told that our depravity would bring apocalyptic wars
and the end of all things, the listener might be uncertain whether
the warning came from a moralizing preacher or a concerned atomic
| In this mental environment, people increasingly
saw the natural world itself as unreliable, quite aside from human
sin or divine punishment. Immanuel Velikovsky and several other would-be
scientists were writing popular books that declared that the Earth
had suffered extremely swift and cataclysmic changes not long ago.
The poles had shifted thousands of miles in only a few years, bringing
sudden floods and ice ages with instantly frozen mammoths as
evidence. These theories deserved scarcely a moment's attention as
science. Yet with titles like Earth in Upheaval, Earth's Shifting
Crust, and Popular Awakening Concerning the Impending Flood,
the catastrophist writings resonated with apocalyptic fears and excited
widespread popular interest.(20)
| The widespread forebodings about the planet's
fate made it easier for scientists to conceive theories of climate
catastrophe and get a hearing. By far the best-publicized theory was
offered in 1956 by two respected scientists, Maurice Ewing and William
Donn. They argued that a warm spell could melt the Arctic Ocean's
ice pack and trigger processes that would bring an ice age. (Link from below) Popularizations, such as a widely read article
on "The Coming Ice Age" by freelance journalist Betty Friedan, speculated
that flooded coasts and other calamities might soon arrive.(21) The publicity brought Ewing dozens of letters over the
next several years from amateur enthusiasts of climate studies, as
well as from cranks with elaborate ice-age theories of their own.(22) Careful science journalists warned that scientists saw
no more in the Ewing-Donn theory than an interesting unproved speculation.
But most writers agreed that significant climate change was possible.(23*)
| Ewing and Donn's theory sounded like a rational
version of ancient myths of climate catastrophe. There had always
been something deeply buried in human consciousness that resonated
with the Nordic myth of Fimbulwinter the future time when three
years without a summer would herald the doom of men and gods. And
something resonated with the annihilating world-flood described not
only in the Bible but in the folklore of many peoples. Images of an
end of the world in ice, in flood or in (nuclear) fire were no longer
confined to the spheres of fable and religion. Underwritten by scientists,
the images were leaking into sensible everyday conversations.
<=Sea rise & ice
| Suspicions of a Human-Caused Greenhouse
TOP OF PAGE
| Now that it seemed plausible that human technology
could alter the planet as a whole, journalists found it easier to
suggest that the greenhouse effect of CO2 from
fossil fuels was a possible cause of global warming. Evidence that
the world had been growing a bit warmer had become strong enough to
convince most meteorologists. In a 1955 news conference, the head
of the U.S. Weather Bureau said that a significant general rise in
average temperature (3.6°F, that is, 2°C) had been seen
in the previous fifty years.(24)
During the 1950s, thorough newspaper readers could repeatedly run
across small items with anecdotes of warming, such as crops and codfish
flourishing hundreds of miles north of their former ranges. Easier
to visualize were stories of mountain glaciers retreating. (That turned
out to be confusing, however, since mountain glaciers advance and
retreat erratically, depending less on global temperature than on
purely local variations in snowfall.) On a larger scale, in 1959 the
New York Times reported that the ice in the Arctic Ocean
was only half as thick as it had been in the previous century. Still,
the report concluded, "the warming trend is not considered either
alarming or steep."(25)
| The respected oceanographer
Roger Revelle took the lead in suggesting that trouble might lie ahead.
When he calculated that a rise in the level of CO2
was likely, Revelle took pains to talk about global warming with science
journalists and government officials. He said that humanity was inadvertently
undertaking a huge "experiment" on the atmosphere, and the phrase
was quickly picked up by others. Revelle meant "experiment" in the
traditional scientific sense a useful logical exercise, with
the rise of CO2 offering a fascinating opportunity
for the study of geophysical processes. But the word "experiment"
increasingly reminded ordinary people of nuclear bomb tests, or even
Frankenstein at work on his monster.
| Revelle himself at times
warned that the experiment might bring serious problems. Testifying
to Congress in 1957, he was one of the first to use another new and
potent metaphor. "The Earth itself is a space ship," he said. The
ventures into space that began with the Soviet launching of Sputnik
in 1957 were pushing many people toward seeing the planet, as if from
outside, as a whole. For Revelle, it meant we had better keep an eye
on the spaceship's air control system. Noting that climate had changed
"quite abruptly" in the past, perhaps bringing the downfall of entire
civilizations in the ancient world, he warned that the rise of CO2 might turn Southern California and Texas into "real deserts."(26) A few newspapers carried
accounts with headlines like, "Fumes Seen Warming Arctic Seas," and
reported Revelle's prediction that the Soviet Union could become a
"great maritime nation" within as little as fifty years.(27)
| Another scientist the
media noticed was the physicist Gilbert Plass, whose own work had
convinced him that CO2 would warm the planet.
In a 1959 Scientific American article he boldly predicted
that global temperatures would rise something like 3°F (1.7°C)
by the end of the century. Plass, thinking as a scientist, only remarked
that this would allow a conclusive test of the CO2
theory of climate change. But the magazine's editorial staff connected
his ideas with the public's growing concern about pollution, printing
a photograph of coal smoke belching from factories. The caption read,
"Man upsets the balance of natural processes by adding billions of
tons of carbon dioxide to the atmosphere each year."(28*) The lesson was clinched
by news in mid 1961 that meticulous measurements by C.D. Keeling had
detected an annual increase of CO2 in the atmosphere.(29)
| Most people did not see anything ominous.
"There would seem to be every reason for producing as much carbon
dioxide as we can manage," one popularization concluded. "It is helping
us towards a warmer and drier world."(30) In any case none of it would happen until the 21st century,
which seemed very distant indeed from the 1950s. The subject was scarcely
noticed by anyone outside the science-minded minority who happened
upon the reports, which were mostly buried in the back pages of newspapers
or dropped into a news magazine as a brief paragraph.
| After all, nothing here was certain, not
even the recent warming trend. In 1961, a Weather Bureau expert announced
that since about 1940 the world had in fact been cooling. Just around
the time scientists had started to become convinced that there was
a long-term warming trend, it had reversed, although the random fluctuations
were so great that it had taken two decades for the reversal to become
plain. (It didn't help that in the world's media capital, New York
City, unusual warm spells happened to continue through the 1950s and
1960s.) For most of the 1960s and 1970s, science popularizations were
dismally confused. A magazine might one year predict a tropical world
with cities drowned by rising oceans, and the following year warn
of cities overwhelmed by glaciers in a sudden ice age. It was uncomfortably
obvious that experts could not agree about the actual trend of climate
change, let alone its possible causes.
| The one unchallenged fact was Keeling's measurement
of the amount of CO2 in the atmosphere. His curve
rose year by year through the 1960s.The rise impressed scientists
who reviewed climate issues on behalf of various committees. A pioneer
was the private Conservation Foundation, which sponsored a 1963 conference
on climate. The scientists issued a report warning of "potentially
dangerous atmospheric increases of carbon dioxide."(31) In 1965, the issue rose to a high level of government,
when a panel of the U.S. President's Science Advisory Committee decided
that the potential for global warming was a matter of serious national
concern. But their report mentioned it only as one brief item among
many other, more troubling environmental problems.(32)
| These reports gave notice that some knowledgeable people were beginning
to worry about how humans might be altering the atmosphere. The anxiety
was only partly provoked by developments in climate science. Equally
important was the historic shift of attitudes about how technology
might affect the natural world. Utopian hopes dissolved as the nuclear
arms race hurtled onward. The vague, almost mythological anxieties
of the1950s were reinforced by specific and immediate fears, voiced
in shrill public debates and mass demonstrations against nuclear weapons
tests. Exquisitely sensitive instruments detected radioactive fallout
from the explosions half a world away the first recognized
form of global atmospheric pollution. By the early 1960s, many in
the public looked with dread on plausible future scenarios. It was
easy to imagine a post-nuclear war world like what a science-fiction
story portrayed later in the decade: the atmosphere so wrecked that
horrible and uncanny storms perpetually swept the discolored skies.(33)
| The lesson of fallout
was that the world's air was no longer pristine, not anywhere. Science
writer Rachel Carson recalled that she used to think "the clouds and
the rain and the wind were God's," but now she knew otherwise. In
her 1962 book Silent Spring she warned that agricultural
pesticides such as DDT and other chemical pollution, drifting around
the world like fallout, could endanger living creatures not just in
the neighborhood of the polluter, but everywhere.(34) Meanwhile scientists reported that
the increasingly despised urban smogs could no longer be attacked
as just a local problem, for the pollution measurably dimmed the skies
a thousand miles downwind.
| These influences and
many others brought a new generation of social critics onto the public
stage. The "conservationists" of an earlier generation had fought
against local harms, the toxic river, the razed forest or stinking
air in their own vicinity. That was the immorality of fouling one's
own neighborhood. Now the moral lesson was still more severe. As poor
farming practices had apparently aggravated the Dust Bowl, as ancient
civilizations had destroyed their lands through overgrazing, so now
human carelessness and greed seemed to endanger the entire global
environment. Rejecting the traditional admiration for technology,
the new "environmentalists" exclaimed that human activities threatened
all life on Earth.
| A new view was growing of the Earth as a
system, an interlocking and fragile whole. Presumably this view was
somehow connected with improved intellectual understandings. For one
thing, discussion of the "population explosion" was teaching people
the fierce power of exponential increase. Experts and public alike
began to foresee trouble as the rise in the number of humans not only
multiplied on itself, but was multiplied again by advances in technology.
The quantity of materials and energy that each individual used was
redoubling even faster than the number of individuals.(35) People were coming to think in global terms not only about
population growth but also about its intricate relationship with the
planet's stock of chemicals and other resources.
|| <=Simple models
|Analyzing such a tangle
seemed impossible.. Nevertheless a few people at the Massachusetts
Institute of Technology, the world center of enthusiasm for computer
modeling, attempted to construct global resource models. Environmental
issues like greenhouse warming were in the back of their minds (we
will see that one of the instigators, Carroll Wilson, was meanwhile
organizing landmark conferences on climate change). Their trail blazing
1972 book on The Limits to Growth proclaimed that the limits
were strict. The computer said that exploding population would use
up all available food and minerals, and if somehow we avoided that,
we would eventually choke in our own polluting exhaust. The book sold
millions of copies worldwide, deeply impressing thoughtful people
with its calculation of "the predicament of mankind." For most of
the public, and policymaking elites too, it was not only the first
time they had faced up to the finite capacity of the planet, but also
the first time they had seen a scientific analysis of the global physical
and economic system.(36)
| Meanwhile scientists
showed how widespread harm might be wreaked by modest quantities of
materials, and not only radioactive fallout or DDT. Meteorologists
calculated, and explained to science reporters, that a modest addition
of ordinary dust or gases to the atmosphere might trigger serious
and unpredictable changes. It was just now, in the mid 1960s, that
climate science one of the few fields that tried to model an
entire planetary system became acutely aware of feedbacks and
the mathematics of chaos. New models of the atmosphere interacting
with oceans and ice raised the possibility of huge and sudden upheavals.
It is not clear how far these intellectual developments affected public
opinion, since most people scarcely heard of them. There may have
been as much influence in the other direction. While models of an
unstable climate had scientific roots stretching back into the 1950s,
scientists may have been encouraged to develop the models when their
thinking expanded along with the shift of public opinion toward seeing
global disruptions as plausible.
|Scientific ideas of any sort meant less to
the public than technological coups, and not just the bomb tests.
Likewise impressive was the photograph that an astronaut took from
lunar orbit in 1968. Here was our small blue sphere, decorated with
lacy whirls of cloud, floating like an oasis in endless black space.
Astronauts and cosmonauts declared with an almost mystical insistence
that from their high viewpoint, national boundaries became invisible
as a global perspective opened up.(37) The photographs, compared with even the most scientifically
informed earlier paintings, showed weather systems that were far more
elaborately organized, more delicate and more ravishingly beautiful
a planet to cherish.
| Threats of Climate Disaster (Early
1970s) TOP OF PAGE
| The first Earth Day, held in
1970, marked the emergence of environmentalism into powerful political
action. New public attitudes supported bitter attacks on authorities,
especially in government and industry. They were the villains held
responsible for pollution and many other problems. To the new breed
of environmentalists, almost any novel technology looked dangerous.
As one example, the press revealed that the U.S. military in Vietnam
had engaged in a massive cloud-seeding program, trying to bog down
the Communist army with rains. The military was now widely despised,
and in the eyes of many around the world, this attempt at climate
modification was malignant. Where once people had held utopian hopes
for the ways humanity would modify the environment, either deliberately
or as a side-effect of "progress," now such "interference" seemed
ignorant, reckless, and perhaps wicked. In every democratic industrial
nation, citizens pressed their government to enact environmental protection
laws. Governments gave way, taking steps to reduce smog, clean up
water supplies, and the like. Meanwhile bureaucracies improved the
organization (and in some cases the funding) of research on the atmosphere,
along with every other element of the environment.
| The new attitudes affected scientists
along with everyone else. Some experts were getting worried about
climate change, and made deliberate efforts to stir up other scientists
and the public. Especially important was a "Study of Critical Environmental
Problems" organized in 1970 at the Massachusetts Institute of Technology.
The organizer was Carroll Wilson, a dynamic science policy entrepreneur
who had earlier managed the U.S. Atomic Energy Commission. Under his
expert leadership, some 40 scientists deliberated for a month over
desertification, pollution of the air and oceans, and other harms.
In their concluding conference report, as the first item in a big
list of potential problems, the scientists pointed to the global rise
of CO2. The risk of global warming, they declared,
was "so serious that much more must be learned about future trends
of climate change."(38) The media paid some attention, although
they mostly overlooked global warming among more immediate pollution
| Wilson followed up the MIT study by organizing
a meeting of experts in Stockholm. This "Study of Man's Impact on
Climate," focused tightly on climate change, was a landmark in the
development of awareness. The group concluded with a ringing call
for attention to the dangers of humanity's emissions of greenhouse
gases and particle pollutants. Their widely read report gave as its
epigraph a Sanskrit prayer: "Oh, Mother Earth... pardon me for trampling
on you."(39) Another example
of the new tone was a deliberately provocative 1971 book titled Impingement
of Man on the Oceans. "The shocking reality," said the author,
"is that the hour is fast approaching when the people of the Earth
will have exhausted nature's ability to adjust to the complexities
of human attack."(40)
| Contemplating the relationship between science and society, some
people would say that the judgment of scientists bent under the pressure
of the mass prejudices of the day. Others would say that public opinion
responded intelligently to new scientific facts. Both views go too
far in separating scientific from popular thought. In regions like
North America and Europe, where the public was relatively well educated
and informed, the views of scientists and public tended to evolve
| Not everyone adopted such thinking. Many
still felt, as the veteran meteorologist Joseph Smagorinsky had declared
in 1969, that "our physical environment must be considered an enemy
to humanity until we master it."(41) But the rhetoric and attitudes of the environmental movement
spread rapidly, not only among the general public but also among climate
researchers. Smagorinsky himself worried in 1972 that we were standing
"at the threshold of a possible crisis which could have as much of
an impact on man as his invention of war."(42)
| Climate was now seen
as one of the planet's vulnerable spots, and many people expected
that whatever we did to it would be for the worse. For example, in
1969 (Feb. 20) the New York Times reported that greenhouse
warming of the Arctic Ocean might make the pole ice-free within a
decade or two. The resulting climate change would turn much of the
United States and Europe from breadbaskets to deserts. On the other
hand, the Times article continued, some scientists held there
was a cooling trend. That too could be blamed on humanity. Increased
dust and other aerosols, stirred up by agriculture and industry, might
bring destructive cold spells.
| Science reporters were
especially impressed by a 1972 warning from the oceanographer Cesare
Emiliani. His ground-breaking research on past climate cycles had
persuaded him that in the natural course of events the present "amiable
climate" should give way, within the next few thousand years, to a
new ice age. But the prediction, Emiliani explained, might be confounded
by human interference such as deforestation and pollution, for the
climate was extremely unstable. "We may soon be confronted with a
runaway glaciation," Time magazine quoted him as saying
or perhaps instead a "runaway deglaciation" that would flood our coastal
cities.(43) The most common scientific viewpoint
was summed up by a scientist who explained that the rise in dust pollution
worked in the opposite direction from the rise in CO2,
so nobody could say whether there would be cooling or warming. In
any case, "We are entering an era when man's effects on his climate
will become dominant."(44)
| Climate pronouncements like this were no longer always hidden in
the back pages. In the early 1970s, the public learned that climate
change could be an urgent problem. What aroused them was a spectacular
series of disasters. In 1972, drought ravaged crops in the Soviet
Union and several other regions; this caught attention around the
world when the Soviet government made massive grain purchases and
prices rose sharply. Also in 1972 the Peruvian
fisheries collapsed because of an El Niño event, while the
Indian monsoon failed (and again in 1974). Meanwhile droughts struck
the Midwestern United States too, severely enough to show up repeatedly
on the front pages of newspapers and in television news programs.
Most dramatic of all, years of drought struck the African Sahel and
reached an appalling peak in 1972, threatening millions with starvation,
bringing on mass migrations and hundreds of thousands of actual deaths.
Television and magazine pictures of sun-scorched fields and emaciated
refugees brought home just what climate change could signify.
| Climate scientists did not know what caused any of this,
but some publicly suggested that humans were partly responsible. Looking
at the disaster in Africa in particular, they speculated that our
pollution of the atmosphere was changing global weather patterns.
Or perhaps overgrazing of the semi-arid Sahel had started a vicious
cycle, where the barren ground reflected more sunlight, altering the
winds so as to cause further desertification. Whatever the cause of
the disasters, they undercut the public's traditional belief that
weather conditions would never get far from their old accustomed pattern.
Climate scientists had already been moving away from that during the
past decade. People increasingly understood that there existed no
such a thing as a "normal" climate, and many began to worry that permanent
shifts were underway.(45)
| The rise in attention can be seen in the popular articles in American
magazines listed in the Readers' Guide to Periodical Literature
under the rubric "Global temperature change." The articles put interviews
of climate scientists alongside the recurring news of droughts and
other weather disasters. In the mid 1970s, the number exploded from
roughly three articles per year to more than twenty.(46) That was still a low level compared with many other issues
that agitated the public. But it was enough so that well-read people
would be generally aware of climate change as a public issue.
| This was not brought about by any deliberate
public relations campaign. Nearly all scientists felt their job was
to pursue research and publish it in technical journals. Anything
important would presumably come to the attention of science journalists
and policy-makers. For really important problems, the scientists could
convene a study group (like the "Study of Man's Impact on Climate"
held in Stockholm in 1971) and issue a report. Experts like Revelle
were more than willing to explain their ideas when asked, and they
might even make an effort to come up with quotable phrases for reporters.
On request they would give a talk on the state of climate science
or write it up for a magazine like Scientific American, which
reached, not exactly the public, but the part of the public that was
well educated and interested in science. This mild part-time activity
was fairly effective, for science journalists did notice and amplify
anything that could make a good story.
| As usual, news media drew attention to the
worst dangers. Various journalists reported that scientists suspected
the weather fluctuations could be the harbinger of another ice age.
To be sure, most articles made it clear that the top scientists frankly
admitted uncertainty. Many scientists believed that cooling was no
more likely than global warming, or than no particular change at all.
Newsweek explained, in a direct quote from a National Academy
of Sciences report, that "Not only are the basic scientific questions
largely unanswered, but in many cases we do not yet know enough to
pose the key questions." Yet there was one thing that nearly all experts
agreed on, news reports explained. As Time put it, "the world's
prolonged streak of exceptionally good climate has probably come to
an end meaning that mankind will find it harder to grow food."(47) When rising population crashed against the increasingly
erratic weather, the world might face widespread famine, even warfare
over the dwindling food supply.
| Perhaps this was not just bad luck. "We have broken into the places
where natural energy is stored and stolen it for our own greedy desires,"
a journalist declaimed. "Our tampering with the delicate balances
of nature can cause major dislocations... and many people intuitively
and logically conclude that some great natural law is about to catch
up with us.... A few see in such catastrophes the just hand of divine
judgment and retribution against materialist sinners..."(48)
| A leader in stirring public anxiety was the respected climate expert
Reid Bryson. Scarcely any popular article on climate in the 1970s
lacked a Bryson quote or at least a mention of his ideas. His big
worry was the increase in smoke and dust, not only from industry but
also from lands laid waste by deforestation and slash-and-burn agriculture.
Already in the late 1960s, he had gone to the public to warn that
such pollution was probably bringing on global cooling.(49) He explained that like the smoke from
a huge volcanic eruption, the "human volcano" could cause disastrous
shifts in weather patterns. His claims were forcefully stated and
unequivocal, backed up by an argument that the droughts in Africa
and India already showed how air pollution was halting the rain-bringing
monsoons. (Three decades later scientists were still unsure about
that, although they suspected that pollution had in fact contributed
to the deadly African drought.) Journalists quoted Bryson's warnings
that the effects of human interference "are already showing up in
rather drastic ways," as Fortune magazine reported in 1974.
We faced unprecedented dangers, the magazine declared, perhaps "a
billion people starving."(50)
Most climate experts thought Bryson went too far, at least as
reported in the media. "There has been much hand-waving of
late," the respected climatologist William. Kellogg complained
in 1971, "and the ‘prophets of doom’ have taken
the spotlight of public attention. Virtually none of these people
who speak of the ‘doom’ of our earthly environment are
scientists..." He insisted that our planet had "a remarkably
stable life-support system" and that "the natural sources
of contamination... still far outweigh all of man’s contributions,
taken on a global scale."
|Yet the majority
of climate experts were beginning to worry. Kellogg himself confessed
to a "haunting realization that man may be able to change the
climate of the planet Earth." A 1974 study by leading figures,
convened by the National Academy of Sciences, concluded that "there
is a finite probability that a serious worldwide cooling could befall
the Earth within the next 100 years." The shift, moreover, could be "rather sudden."(51) Another official (or
official-sounding) endorsement came in 1976 with the publication of
a secret 1974 report by the Central Intelligence Agency. The report’s
authors, relying on Bryson’s theory, gave dire warnings that
impending cooling could bring economic dislocation and perhaps even
wars. "There would be increasingly desperate attempts on the part
of powerful but hungry nations to get grain any way they could. Massive
migrations, sometimes backed by force, would become a live issue..."
Climate scientists publicly attacked the CIA report as "sloppy" and
full of "patent nonsense" (Bryson himself had to spend a good part
of the next year explaining to people that he wasn't responsible for
what it said). However, news accounts went on to say that nearly all
scientists did admit that severe climate variations were possible.(52)
| News of these reports and studies was still
relegated to a few paragraphs on the inside pages of the better newspapers
or in the science-and-culture section of news magazines, reaching
only the more alert citizens. This limited but important audience,
if they happened to open to the right page on the right day, might
notice a significant discovery. Strong new evidence showed that the
coming and going of ice ages followed a rhythm set by predictable
astronomical variations of the Earth's orbit around the Sun. Projecting
these orbital variations forward, several experts calculated that
we were now in the descending part of the natural cycle, with the
onset of the next ice age probably scheduled to come within the next
few thousand years. (It would be a couple of decades before more accurate
calculations showed that the next scheduled ice age was not due for
tens of thousands of years.) A few scientists argued that it would
be prudent to make preparations for the possibility that cooling would
begin to get serious within the next century or two. After all, journalists
pointed out, weather records revealed widespread temperature declines
since the 1950s. (Later studies would find the cooling had come only
in the Northern Hemisphere, and particularly in the much-watched North
Atlantic region. It didn’t help that the 1970s brought especially
cold weather to the world’s media capital, New York City.)
| Popular articles occasionally summarized the scientific debates.
The respected oceanographer James Hays, for example, told the elite
Saturday Review audience that within a few centuries "it
may very well get cold enough to allow great glaciers thousands of
feet thick to cover North America as far south as Long Island." While
acknowledging that other scientists predicted that greenhouse warming
could cancel out the natural trend toward the next ice age, Hays warned
that more pollution, by blocking sunlight, "could tip the balance"
and bring on the ice age even faster.(53) Members of the public who wanted
to read more about all this could find a book-length popularization
of the ideas of Bryson and like-minded scientists in The Cooling.
The journalist author warned that "we could possibly witness the beginning
of the next Great Ice Age. Conceivably,... we would see mass global
famine in our lifetimes, perhaps even within a
decade." That compressed into a decade glacial processes that
scientists expected must take hundreds if not thousands of years.
It went far beyond what even Bryson had suggested (he provided a preface
to the book, but used the opportunity to warn that it was neither
scientifically accurate nor balanced). Most reviewers rightly dismissed
The Cooling and a few similar publications as mere sensationalism,
if they noticed them at all. (54)
| Still, Bryson's group had found evidence that climate really could
change severely in the course of only a few decades. Journalists promptly
reported this to the public, and trotted out the old theory of Ewing
and Donn about the sudden onset of an ice age (not overlooking the
tale of mammoths found buried in permafrost with grass in their stomachs).
Some scientists "even believe the glaciers could return within our
lifetime," exclaimed a science writer in the Saturday Evening
Post. (See above) This was more scientific nonsense, and Bryson
remarked indignantly, "I am probably the most misquoted climatologist
in the United States."(55)
| In truth, scientific opinion was shifting toward
the idea that small perturbations could trigger sudden climate change.
Abstract theoretical studies were showing how a complex system of
feedbacks like climate could even lurch all on its own, unpredictably.
The Saturday Evening Post article correctly cited studies
from lake sediments and ice cores that hinted that severe cold could
descend in as little as a century.(56) A slower global warming seemed more
likely to many experts. A few scientists, however, suggested that
if global warming was underway it might release a mountainous surge
of ice from Antarctica. By cooling down the oceans that could bring
an ice age, perhaps within decades.
| The ideas seemed plausible to Nigel Calder, a respected British
science journalist, who featured them in a two-hour television feature
about weather that was broadcast in 1974. One short but memorable
segment warned of a possible "snowblitz" set off by an Antarctic ice
surge, or directly by global warming or pollution, or just by pure
chance. Entire countries could be obliterated under layers of snow,
said Calder, and billions would starve. The new ice age "could in
principle start next summer, or at any rate during the next hundred
years." This was the first time the threat of abrupt climate change
appeared as the subject of a major television presentation.(57) But it was an isolated case, and it did not reach beyond
the minority who watched educational shows on public television. Climate
change was not yet a topic of widespread public discussion.
| Atmospheric Scientists and Industrial
Policies (Latter 1970s) TOP OF PAGE
| A few scientists thought the prospects
of a calamity were so serious that they must make a personal effort
to address the public directly. Bryson wrote a book titled Climates
of Hunger, published in 1977. Drawing on his group's historical
researches, he described how native American societies had been destroyed
by the sudden onset of prolonged droughts, far worse than anything
known in recent centuries. A better-documented historical case, noted
by many writers, was the "Little Ice Age" that had chilled the North
Atlantic region from the 15th through the 18th century. Starvation
had loomed as crops failed in the dank summers, the Thames at London
and the Baltic Sea had frozen solid in winter, while advancing glaciers
had crushed entire villages in the Alps and Viking
colonies in Greenland had collapsed.(58) Bryson
warned that such disasters could hit our own civilization unpredictably
| Another climatologist who worked hard to warn of a possible climate
calamity was the young Stephen Schneider. He and his journalist wife
wrote a popularizing book, The Genesis Strategy: Climate and Global
Survival. Insisting that climate could change more quickly and
drastically than most people imagined, they advised the world to devise
policies to cushion the shocks, such as building a more robust agricultural
system. As Joseph had advised Pharaoh in the Book of Genesis, we should
prepare for lean years to follow fat ones.(60)
| A few experts stirred public interest with
ideas of still more drastic action: enormous global engineering projects
to deliberately bend the climate to our will. Most scientists dismissed
the ideas, but not because they sounded like science fiction. It seemed
only too plausible that humanity could alter the climate. However,
our knowledge was so primitive that any intervention might only make
| Some scientists criticized Bryson, Schneider,
and others who spoke directly to the public. The time spent writing
a book and going about the country delivering public lectures was
time away from doing "real" science. Worse, most scientists felt that
any definite statement about climate change was premature. After all,
nobody had published a confident prediction of an imminent ice age
in a scientific journal. [See discussion and references by RealClimate
and W. Connolley.]
The whole subject was so riddled with uncertainties that it seemed
unfit for presentation to the scientifically naive public. Experts
whose profession demanded accuracy were upset by the shortcuts some
colleagues took when explaining things in lay language. They particularly
disliked the blunt and colorful statements, inevitably imprecise,
that were necessary to catch the public's ear. Since debate over the
likelihood of severe climate change had become a salient public issue,
any statement might be dragged into the media arena. Reporters were
quizzing experts at scientific meetings and telephoning them with
urgent questions about one or another discovery that was about to
be published. Climate science professionals, accustomed to life in
a quiet academic backwater, found the change both gratifying and disturbing.
| Many of the experts felt that the climate controversy was inflated
by a few irresponsible scientists and sensation-seeking journalists,
agitating for no good reason. As the Director-General of the United
Kingdom Meteorological Office explained in a 1976 lecture, the official
message was, "no need for panic induced by the prophets of doom."
With other meteorologists, perhaps the majority, he insisted that
"the climatic system is so robust, and contains so much inherent stability
through the presence of negative feedback mechanisms, that man has
still a long way to go before his influence becomes great enough to
cause serious disruption...."(61*) In fact the
public showed no signs of panic nor even much anxiety. The traditional
belief in the benign "balance of nature" was still widely held. Warnings
of a future climate calamity sounded no different from the countless
other future threats that newspapers had been trumpeting for a hundred
| We don't know the public's response for sure,
since nobody took a poll. But a largely indifferent attitude is suggested
by the very lack of polling, or any other distinct reaction by the
experts who kept their finger on the public pulse. Politicians, even
better attuned to public feelings, did show some desultory reactions.
A few bills dealing with climate were proposed in the U.S. Congress,
and the administration undertook a mild reorganization of climate
research. But most politicians showed little interest in the topic.
| Yet climate change was becoming a political issue, if only in the
narrow sense that policies were at stake. At professional meteorological
conferences, debates over technical questions such as the rate of
CO2 buildup became entangled with debates over
how governments should respond. In some meetings scientists addressed
the policy issues formally in papers and working groups, struggling
with questions far beyond their professional expertise. How much should
reliance on fossil fuels be reduced, if at all? Should the destruction
of tropical forests be a main target for reform? How much money and
effort should be spent on averting climate change, amid the struggle
to feed the world's poor? With demands for equity rising and centralized
government threatening freedom, what policies were desirable? Or even
politically feasible? Which was more dangerous to exclaim about
the worst possible harms, and give science a reputation for sensationalism,
or to offer cautious scenarios, which might delay action until it
was too late? Was it even proper for a scientist to speak, as a scientist,
on social questions?(62)
| The different approaches showed up in exchanges
like the following, at a 1972 symposium where scientists argued over
intractable calculations on how much CO2 was
emitted during deforestation. "I guess I am rather conservative...,"
one expert remarked. "I really would like to see a better integration
of knowledge and better data before I would personally be willing
to play a role in saying something political about this." A colleague
replied, "To do nothing when the situation is changing very rapidly
is not a conservative thing to do."(63)
| Unable to agree even whether the world was likely to get warmer
or colder, the scientists did unanimously agree that the first step
must be to redouble the effort to understand how the climate system
worked. Calls for research always came naturally to researchers, but
from the early 1970s onward, climate scientists issued these calls
with increased frequency and passion. Even in technical articles in
professional journals, many authors now went out of their way to state
that an increased research effort was urgently needed. Interviewed
by journalists, most climate scientists said they required far more
data and analysis. In other words, governments should put up more
money. As one meteorologist put it, "public opinion is being alerted
and thus politicians may be able to act."(64)
| Not only more funds,
but better organization seemed necessary. Individual scientists were
backed up by official committee reports pressing these issues. In
particular, around 1974 American scientists made a concerted effort,
both in public and behind the scenes among officials, to urge their
government to found a National Climate Program. That would give them
both unified direction and sharply increased funding. Gathering data
and organizing research on climate change, one expert explained, "should
be regarded as an important aspect of national defense, or, more accurately,
of defense of the entire planet against a common
threat."(65) Scientists also pushed for heightened international efforts.
In the absence of a truly global public opinion, this action tended
to be mostly hidden within conferences and in the corridors of bureaucracies.
| A few people began to look beyond the corridors of research policy
and publicly demanded immediate changes on a broader scale. Environmental
activists were already attacking overgrazing, smog emissions, and
so forth because of the damage in their neighborhoods. Such bad practices
might alter the climate as well. But this only added one more item
to the list of arguments against specific practices. During the 1970s,
only a few people speculated that it might be wise to impose serious
changes on industry and agriculture for the special purpose of reducing
their impact on climate. That was a world away from practical politics,
rarely suggested even as an abstract future goal.
| An example of the auxiliary
part played by climate worries came up during a controversy that gathered
around itself much of the political attention that could be spared
for the atmosphere. This was a public debate that began in 1970 over
the U.S. government's plans to subsidize a fleet of supersonic commercial
airplanes. The transports would inject large amounts of water vapor
and chemical aerosol particles into the stratosphere, and some scientists
warned that this could have damaging effects on global climate. The
public's main worries, however, were that the fleet would be intolerably
noisy, damage the high ozone layer that protected them from skin cancer,
and waste taxpayers' money. Under pressure from the entire list of
objections, in 1971 Congress cancelled the project, perhaps the first
time in American history such a major technological initiative was
defeated by public pressure invoking environmental arguments.(66)
| Pursuing the new concern for the stratosphere,
in 1974 two scientists noticed that certain obscure gases produced
by industry (nicknamed "CFCs") lingered in the atmosphere. Some would
drift up to the stratosphere where, the scientists discovered, ultraviolet
rays would activate them in a process that destroyed ozone. The high,
thin layer of ozone blocks the Sun's ultraviolet rays, so removing
this layer would cause an increase of skin cancers, and perhaps bring
still worse dangers to people, plants, and animals.
| CFCs were the propellents in aerosol sprays:
every day millions of people were adding to the global harm as they
used cans of deodorant or paint. Science journalists alerted the public,
and environmentalists jumped on the issue. Chemical industry groups
fought back with public relations campaigns that indignantly denied
there was any risk whatsoever. Unconvinced, citizens bombarded government
representatives with letters and boycotted spray cans. A survey showed
that nearly three-quarters of Americans had heard about the issue.
In 1977, the U.S. Congress added restrictions on the spray can chemicals
to the new Clean Air Act.(67)
|Climate change was nowhere to be seen in the spray can controversy.
But the threat to the ozone layer sent a stinging message about how
fragile the atmosphere was, how easily human activity might damage
it. And how unexpectedly. Except for the chance circumstances that
had stimulated studies of high-altitude airplanes, the danger from
spray can propellants might have gone unnoticed for quite a few more
| The ozone story added to the shapeless fears that human activity
was somehow endangering the entire planetary atmosphere. The majority
of citizens found it hard to distinguish among the various materials,
whether airplane and automobile emissions, agricultural chemicals,
or industrial pollution from either traditional smokes or bizarre
new substances. Many scarcely distinguished among climate change from
greenhouse warming, ozone damage from CFCs, and health threats from
automobile tailpipes and power plant smokestacks. It was enough to
feel that an eerie toxic smog threatened the entire planetary environment.
| Scientific results continued to trickle in. None of the new studies was especially
striking or definitive, but there was a significant overall tendency.
It seemed that climate could indeed be more delicately balanced, more
subject to swift changes, than scientists had supposed. An example
of the claims that briefly caught the public eye were studies that
suggested that severe droughts in western America followed a cycle,
driven by changes in the number of sunspots. It was a reminder that
the climate might be sensitive to all sorts of small and unexpected
influences. That was driven home to scientists by new data on ancient
climates, observations of disturbingly large annual shifts in the
amount of snow cover in the Arctic, and novel theoretical models that
showed how such changes might make the climate system flip abruptly
from one state to another. This idea of runaway climate became terribly
vivid to both scientists and the public when space probes brought
news of a hellish furnace atmosphere on Venus and a permanent ice
age on Mars.
<=Venus & Mars
| Meanwhile new studies convinced an increasing number of scientists that,
given a choice between warming and cooling, it was the greenhouse
effect that would dominate sooner or later. Theoretical work on aerosols
suggested that human smog and dust might not cool the atmosphere very
much after all. At most, the increased pollution might bring a mild
cooling that would only temporarily mask greenhouse warming. Other
studies suggested that the greenhouse effect might already be changing
the weather. Computer models, although still provisional, tended to
agree that the rising level of CO2 would bring
a degree or so of warming within decades. Any statement that invoked
supercomputers commanded strong respect from the public, and from
most scientists too.
| Climate experts were
quick to explain the new findings. A well-respected geochemist, Wallace
Broecker, took the lead in 1975, warning in an influential Science
magazine article that the world might be poised on the brink of a
serious rise of temperature. "Complacency may not be warranted," he
said. "We may be in for a climatic surprise."(68) In 1977, the National Academy of Sciences weighed in with
a major study by a panel of experts who warned that temperatures might
rise to nearly catastrophic levels during the next century or two.
The report, announced at a press conference during the hottest July
the nation had experienced since the 1930s, was widely noted in the
|Science journalists, by now closely attuned
to the views of climate scientists, promptly reflected the shift of
opinion. Media talk of a ruinous new ice age continued through the
winter of 1976-1977, which was savagely cold in the Eastern half of
the United States. But that was the end of it. From 1978 on, nearly
all articles on climate in the New York Times were oriented
toward greenhouse warming. In the Readers' Guide listing
of U.S. popular articles, warnings about climate were more or less
evenly divided between heating and cooling up to 1977, but then articles
about global warming took over almost completely.(70*)
As an example of the change, in 1976
the U.S. News & World Report described (with strong
qualifications) the theories that the world would be getting cooler.
The very next year the same magazine reported that "The world may
be inching into a prolonged warming trend that is the direct result
of burning more and more fossil fuels..." The ice-age theories,
said the article, "are being convincingly opposed by growing evidence
of human impact."(71) Similarly, in 1976 Business
Week had explained both sides of the debate but reported that
"the dominant school maintains that the world is becoming cooler."
Just one year later, the magazine declared that CO2
"may be the world's biggest environmental problem, threatening to
raise the world's temperature" with horrendous long-term consequences.(72*)
|The change in press coverage was not due
to any obvious change in the weather — the winter of 1978-79
was the coldest on record for the United States. Nor was there any
single scientific revelation, for amid the complexities of geophysics,
no individual finding could ever be decisive. But several research
results published in the mid 1970s (perhaps especially from supercomputer
models) swayed the opinions of scientists. In early 1978 the New
York Times reported that a poll of climate scientists found
them evenly divided on whether there would be warming, cooling,
or no particular change. But the balance among the handful of top
experts had shifted strongly away from any serious cooling and toward
the likelihood of warming. In the real scientific journals, where
articles are published only after critical review by scientist peers,
during the 1970s only two or three articles had appeared that projected
cooling, and none of these were published late in the decade. There
were 15 papers that discussed warming or cooling factors without
reaching a conclusion, and 26 that projected warming. (Most of these
articles were published after 1974, for the subject had attracted
very few scientists earlier.) The views represented in the scientific
literature migrated, with the usual exaggeration and simplification,
to science journalists.(72a)
| In all this the journalists conveyed two
important points to the public. One of these points would be obvious
to anyone who read just the headlines and titles of the various articles:
scientists remained uncertain and divided about what would really
happen. The other point crept in on a deeper level. It was put explicitly
in a 1977 Readers' Digest article where the author, after
emphasizing the disagreement among experts about whether the planet
would get too hot or too cold, stated his principal conclusion. "All
scientists agree that a new factor has entered the game of climate
change, a 'wild card' never there before man himself."(73)
| Not only future weather,
but weighty questions of present policies were at stake. The worries
about climate change became entangled in debates about fuel supplies.
The "oil crises" of 1973 and 1979, when gasoline became shockingly
expensive or even unobtainable, aroused a keen public interest in
energy policy. Environmentalists were mobilizing public opinion to
block nuclear power. But their preferred technology of solar power
was a long way from being cheap enough (or even environmentally friendly
enough) to fuel the nation. The remaining alternative was a rapid
boost in coal burning. Experts, including a minority of environmentalists,
pointed out that coal might be worse than nuclear power because of
its polluting emissions, including greenhouse gases. Some officials
in the government energy establishment called for intensive study
of global warming, in case the threat turned out to be severe. "If
the CO2 problem looks big enough," one of them
promised, "we'll make changes and fast."(74*)
| These arguments only reached limited circles
in government and industry, scarcely penetrating public consciousness.
The sense of urgency about climate change was dwindling away. It had
never been very strong, even during the droughts and famines of the
early 1970s. By the end of the decade, the collapse of doom-filled
claims about an imminent ice age, replaced by uncertain speculations
about possible future warming, left little for the media to bite into.
The widely reported debates over the speculations of a few scientists,
added to confusion about whether even the observed temperatures were
falling or rising, convinced many people that the science was too
foggy to be worth much attention. Moreover, the basic climate concern
of "food security" the dread of famine that haunted everyone
from grandmothers to policy makers sank out of view for the
first time in human history. In the 1970s, the biotechnology "green
revolution" burst upon farmers. By the end of the century, world food
prices would decline in real terms by some 70%. Neither famine nor
anything else relating to climate change seemed immediately worrisome.
The topic settled down as a mildly interesting public issue, far less
urgent than many others.
Click here for continuation:
The Public and Climate, since 1980
1. The classic discussion is Glacken
(1967); see also Neumann (1985).
2. Fleming (1990); Fleming (1998), ch.s 2-4; Stehr and
von Storch (2000), introduction and chapter 4; the latter is a translation of Brückner (1890), chapter 1, including "psychological
puzzle" on p. 115-16 of Stehr.
3. Price (1995), pp. 59, 69.
Actually every arctic hiker knows how swiftly a freeze can come and how a shifting riverbed can
bury the careless in permafrost.
4. Callendar, personal notes, Nov. 1960, Schove-Callendar
Collection, Climatic Research Unit, University of East Anglia, Norwich, UK, quoted by Peter
Brimblecombe and Ian Langford, "Guy Steward [sic] Callendar and the increase in global carbon
dioxide," paper presented at meeting of Air & Waste Management Association, San
Antonio, Texas, June 1995 (paper 95-WA74A.02, available from AWMA).
5. Thus Callendar in his landmark paper argued in 1938 that
growing efficiency had stabilized the amount of gas production in the previous 20 years, ignoring
the Depression's effects, Callendar (1938), p. 231; Plass
implicitly assumed linear growth in calculating that it would take a thousand years to use up
known reserves of coal and oil, Plass (1956), p. 149; similarly in
the crucial paper Revelle and Suess (1957).
6. Arrhenius (1908), p. 63.
7. Callendar (1938), p. 236.
8. Ekholm (1901), p. 61.
Revision of a paper first published in Sweden in 1895.
8a. Miyazawa (1932).
My thanks to Kooiti Masuda for this information. BACK
9. Time (1939); other examples:
Kimble (1950); Abarbanel and
McCluskey (1950); here and below, see also Fleming
(1998), pp. 131-32.
10. H.T. Kimble quoted Time
11. "Deluge... new food-producing areas:" Abarbanel and McCluskey (1950), p. 63; a widely read book (first
printing 100,000 copies) warning of floods and drought was Baxter
(1953); Baxter was disparaged e.g. by Bello (1954).
12. For racist-tinged concern that heat is enervating: e.g., Huntington (1916); Sears (1953),
p. 43 (note also Shapley's preface, p. vi); Coon (1953);
discussion of Huntington in Fleming (1998), ch. 8; Coughlan (1950) (condensed in Readers' Digest, Nov. 1950).
13. "Do not know": Time
Thirty years hence: Editorial (probably by W. Kaempffert), New York Times,
Aug. 10, 1952, section IV. BACK
14. For example, Engel (1953).
15. Baxter (1953), p. 69.
16. For the anti-smoke movement, Stradling (1999); on air pollution and pollution in general, McNeill (2000).
17. Harrison (1982), p. 737.
18. Weart (1988), p. 187 and
passim; "large numbers:" This Week, condensed as Robbins
(1956), p. 83; further references are in Hart and
Victor (1993), pp. 647-48 and n22. BACK
19. Weart (1988), ch. 4, also
pp. 296-99 and passim.
20. Velikovsky (1955),
mammoths p. 4; Hapgood (1958), mammoths ch. 8; Brown (1948) (an example of a crank pamphlet), mammoths p. 9;
for further references, see Huggett (1990), pp. 119-21.
21. Friedan (1958), also
published condensed in Reader's Digest, DATE??.
22. Folder "Ice Age Fan Mail," preliminary box 52, Maurice
Ewing Collection, Center for American History, University of Texas at Austin.
23. "Unproved speculation:" Cowen
(1960), pp. 186-89, who also put any ice age centuries in the future.
Another example: "the beginning of the next glacial era might still
be breathing down our necks," but "Much time and study and additional
evidence will be necessary before even an informed guess can be made:"
Andrist (1960). BACK
24. F.W. Reichelderfer at WMO Congress, New York
May 18, 1955. BACK
25. Helmut Landsberg reported in the New York
Feb. 15, 1959. BACK
26. United States Congress (85:2)
(1957), pp. 104, 105, 106; one popular writer who took up the "experiment" term (quoting
the Woods Hole oceanographer Columbus Iselin), was Robert C. Cowen, "Are men changing the
Earth's weather?" Christian Science Monitor, Dec. 4, 1957, see Cowen (1960), pp. 181-82; the "spaceship earth" trope was
popularized a decade later by Buckminster Fuller, see Jasanoff
(2001), p. 319.
27. Lloyd Norman for Chicago Tribune Press Service, as
seen in Washington Post 19 March, 1956. BACK
28. Plass (1959); Plass's 1953
calculation of a somewhat more gradual rise was carried earlier in the media in small notes, e.g.,
the climate may be "getting about 1-1/2 degrees hotter per century," Newsweek (1953).
29. New York Times, Sept. 11, 1961.
30. Cook (1957), p. 121.
31. Conservation Foundation, Annual Report for
pp. 19-20, see Conservation Foundation (1963). BACK
32. President's Science Advisory
33. Zelazny (1969). Later
made into a B movie (1977, directed by Jack Smight). Based on a novelette
that I read in 1967 in Galaxy magazine I remember some
of the scenes vividly even now. BACK
34. Carson quoted in Graham
(1970), p. 14; on all this, see Weart (1988), pp. 323-25.
35. E.g., Ehrlich and Holdren
36. Meadows et al. (1972);
37. The influence of the Apollo pictures of Dec.1968
(Earthrise over the Moon, by William Anders) and Dec.1972 (the Whole Earth)
cannot be proven but many have testified to it. Like all great symbols
the Whole Earth was exploited for diverse purposes, see Garb
(1985); Jasanoff (2001), pp. 316-17; Maher
(2005); for astronauts, White (1987). BACK
38. SCEP (1970), p. 12; see
also Matthews et al. (1971); Kellogg
(1987), pp. 120-22.
39. Wilson and Matthews
(1971), p. v.
40. Hood (1971), p. v,
"provocative" p. vi.
41. Smagorinsky (1970), p. 25,
from a talk at an August 1969 conference.
42. McIntyre (1972), p. 37.
43. New York Times, Jan. 27, 1972. Quote: Time (1972). BACK
44. G.S. Benton, chair of Johns Hopkins Dept. of Earth
& Planetary Sciences, to 1970 National Academy of Sciences symposium, New
York Times, April 30, 1970. BACK
45. Henderson-Sellers and Robinson
(1986), pp. 10-11.
46. My counts. A sharp increase in coverage in magazines and
newspapers in the mid 1970s is also reported by a qualitative survey, Harrison (1982), p. 737.
47. harbinger: Time (1974);
Academy report: Newsweek (1975); Time (1974), p. 83.
48. Ponte (1976), pp. 234-35.
49. Bryson (1967).
50. Alexander (1974),
quote p. 92; current thinking on the drought: Rotstayn
and Lohmann (2002). BACK
51. Kellogg (1971), pp.
123, 131; GARP (1975), p. 189, from
App. A (pp. 186-90) by J. Imbrie, W.S. Broecker, J.M. Mitchell, Jr., J.E.
Kutzbach. New York Times, Jan. 19, 1975, p. 31.
52. Central Intelligence Agency, "Potential implications
of trends in world population, food production, and climate," OPR-401, Aug.
1974, published as Appendix II to Impact Team (1977),
quote p. 200. News of the report was first published in the New York Times,
May 1, 1976, p. 2; scientists quoted: U.S. News & World Report (1976); Bryson, personal
communication, 2002. BACK
53. Hays (1973), quotes p. 29,
54. Ponte (1976),
p. xiv. Peterson and Connolley (2007) discuss
all this in detail. BACK
55. "Within our lifetime," Wolkomir (1976), p. 50. "I am a little touchy
about this point," Bryson added. Bryson testimony, May 26, 1976, United
States Congress (94:2) (1976), p. 211. BACK
56. Mammoths frozen "swiftly in their tracks," Impact Team (1977), p. 19; trigger ice age:
Rasool and Schneider (1971), see comment here
on their paper; for lake sediments Wolkomir, op. cit., quotes
David W. Folger, and for ice cores C. Langway, p. 78.
57. "The Weather Machine," BBC-television (a co-production
with the U.S. Corporation for Public Broadcasting and WNET), first aired 20 Nov. 1974,
expanded in a book: Calder (1975), quote p. 134; he based the
"snowblitz" idea on Lamb and Woodroffe (1970); see also Brooks (1925), pp. 90-91.
58. Fagan (2000).
59. Bryson and Murray (1977).
60. Schneider and Mesirow.
(1976), esp. chap. 3; Kellogg and Schneider (1974); Hammond (1976); Glantz (1977).
61. B.J. Mason, speaking mainly about aerosols and ozone. He
admitted that greenhouse warming could become significant in 50-100 years. Gribbin (1976); Mason (1977).
62. Stumm (1977), articles by
A.M. Weinberg and R. M. Rotty, pp. 225-39, by H. Brooks, pp. 241-52, report by A. Nir et al.,
pp. 312-22, and passim.
63. Reiners and Olson at 1972 Brookhaven Symposium in
Biology, Reiners (1973), p. 327.
64. Bert Bolin in McIntyre
(1972), p. 253.
65. Barrett and Landsberg
(1975), p. 79.
66. Horwitch (1982), pp.
67. Gribbin (1988); also Dotto and Schiff (1978); Roan
(1989), see p. 58.
68. Broecker (1975), reported
in New York Times, Aug. 14, 1975, p. 24. Influence of Broecker on a
member of the President's Council of Economic Advisers is reported in New
York Times, June 3, 1977, IV p. 13. BACK
69. National Academy of Sciences
(1977); reported: e.g., New York Times, July 25, 1977, p. 1, and
Business Week (1977). BACK
70. My counts based on titles (for a given article the
titles are all that most of the public reads). A compilation of cooling
scare quotes includes items from 1971 and especially from 1975 to 1977
and none later, Bray (1991).
71. U.S. News & World
Report (1976); U.S. News & World Report (1977).
72. Business Week (1976);
Business Week (1977).
New York Times, Feb. 18, 1978, p. 9. Journals: Peterson
and Connolley (2007). BACK
73. Matthews (1977),
p. 92. BACK
74. P.C. White of ERDA, quoted Business Week (1977). My own serious awareness of the
greenhouse effect began ca.1980 when I began to study pro- and anti-nuclear
power arguments; see the brief mention at Weart
(1988), p. 338. BACK
copyright © 2003-2007 Spencer
Weart & American Institute of Physics