Climatology as a Profession
Until the middle of the 20th century, the discipline of climatology was a stagnant field preoccupied with regional statistics representing a static "normal" climate. The study of climate change (what to many climatologists seemed a contradiction in terms) was only an occasional interest of individuals who worked in divergent ways, and scarcely knew of one another's existence. It had little to do with meteorology, which itself was predominantly a craft that paid scant attention to physical theory. The Second World War and Cold War promoted a rapid growth of meteorology, which some practitioners began to combine with physical science in hopes of understanding global climate dynamics. But the dozen or so scientific disciplines that had something to say about climate were largely isolated from one another. In the 1960s and '70s, worries about climate change arose and began to push the diverse fields into contact. Scientists interested in climate change kept their identification with different disciplines but increasingly developed ways to communicate across the boundaries, for example in large international projects. Around the turn of the 21st century the Intergovernmental Panel on Climate Change institutionalized an unprecedented process of exchanges; its reports relied especially on computer modeling, which became a center of fully integrated interdisciplinary cooperation. (See also the essay on International
"We cannot hope to understand the causes
of climatic stability or change by restricting ourselves to any one field
of earth science. Nature is ignorant of how our universities are organized..."
The Old Climatology
|| - LINKS
|| At the middle of the 20th century the professional study
of climate was a scientific backwater. People who called themselves
"climatologists" were mostly drudges who compiled statistics about
weather conditions in regions of interest the average temperatures,
extremes of rainfall, and so forth. That could have offered a broad
global perspective, but most climatologists set the planet as a whole
aside and attended to regional problems. The people who needed climate
information were farmers planning their crops and engineers designing
dams or bridges.(2) This did not mean climatologists overlooked unusual weather,
for it was precisely the decade-long drought or unprecedented flood
that most worried the farmer or civil engineer. But people saw such
catastrophes as just part of the normal situation, transient excursions
within an overall state that looked permanent on the timescale of
human society. The job of the climatologist was to remove uncertainties
with statistics, fixing the probable size of a "hundred-year flood"
and so forth.
More discussion in
|Most historians of science have painted a different picture, focusing their writings on a handful of scientists in other fields who speculated about climate. Since ancient times many people wondered about gradual changes on a regional scale; starting in the mid nineteenth century the discovery of the ice ages and other great perturbations in the geological record raised questions about climate change on a global scale. The physical chemist Svante Arrhenius, the geologist T. C. Chamberlin, the engineer G. S. Callendar, and others took time away from their regular careers to publish works that were innovative and, given the broad range of their explanations, interdisciplinary. In retrospect these were pioneering contributions to the study of climate. A good many other scientists published speculations that are now justly forgotten. However, none of this was of much interest to people engaged in the professional discipline of climatology: their concern was the climate of the present.
| Typical was the situation
at the U.S. Weather Bureau, where an advisory group reported in 1953
that climatology was "exclusively a data collection and tabulation
business."(3) Not much money
or administrative attention was committed to such work, nor were the
intellectual prospects enticing. To the extent that workers had research
plans, their aim was just to find better ways to synthesize piles
of data. A climatologist was somebody who described climate —
mainly at ground level, where the crops and structures were found.
These climatologists' products were highly appreciated by their customers
(such studies continue to this day). And their tedious, painstaking
style of scientific work would turn out to be indispensable for studies
of climate change. Still, scientists regarded the field (as one practitioner
complained) as "the dullest branch of meteorology."(4) Another expert remarked that in the study of climates, "the
scientific principles involved are barely mentioned... Whether they
are right or wrong does not seem to be of any moment, because they
are never used to calculate anything."(5)
| When climatologists
did try to go beyond statistics to explanations, they would explain
the temperature and precipitation of a region in geographical terms
the sunlight at that particular latitude, the prevailing winds
as modified by mountain ranges or ocean currents, and the like. The
explanations were chiefly qualitative, with more hand-waving than
equations. This was close to the field called physical geography,
a matter of classifying climate zones, with less interest in their
causes than their consequences. If in the first half of the 20th century
you looked in a university for a "climatologist," you would probably
find one in the geography department, not in a department of atmospheric
sciences or geophysics (hardly any of the latter departments existed
anyway). The geographical way of explaining regional climates was
an essentially static exercise loosely based on elementary physics.
The physics itself was useless for telling farmers what they needed
to know. Attempts to make physical models of the simplest regular
features of the planet's atmosphere (for example, the trade winds)
failed to produce any plausible explanation for how the winds circulated,
let alone for variations in the circulation.
| This failure was hardly surprising, since meteorologists did not
have an accurate picture of what they were trying to explain. Few
measurements existed of the winds and moisture and temperature above
ground level, and even ground-level data were scanty for vast portions
of the globe. Most textbooks of climatology accordingly stuck to listing
descriptions of the "normal" climate in each geographical zone, compiled
by authors who, as one scientist complained, "know little, and care
less, about mathematics and physical science."(6)
| Climatology could hardly be scientific when meteorology itself
was more art than science. If the general circulation of the atmosphere
was a mystery, still less could anyone calculate the course of storm
systems. People had a variety of techniques for making crude weather
forecasts. For example, while climatologists tried to predict a season
by looking at the record of previous years, meteorologists similarly
tried to predict the next day’s weather by comparing the current
weather map with an atlas of similar weather maps from the past. More
often a forecaster just looked at the current situation and drew on
his experience with a combination of simple calculations, rules of
thumb, and personal intuition.
| This craft had little to do with scientific advances. As one expert
remarked ruefully as late as 1957, the accuracy of 24-hour weather forecasts
had scarcely improved over the preceding 30 or 40 years. A canny amateur
with no academic credentials could predict rain at least as successfully
as a Ph.D. meteorologist, and indeed most of the "professionals" in
the U.S. Weather Bureau lacked a college degree. Aside from a handful
of professors in a few pioneering universities (mostly in European
geophysical institutes), meteorology was scarcely seen as a field
of science at all, let alone a science firmly based on physics. Meteorology,
one academic practitioner complained to another in 1950, "is still
suffering from the trade-school blues."(7)
|Since the 19th century the forecasters and statistical climatologists had gone their separate ways. Neither group had much to do with the few professional academics, trained in physics, who from time to time attempted to analyze weather patterns with equations. Much of this work led nowhere and is now forgotten, but some laid the groundwork for later progress. Historians of science have naturally focused on the pioneering efforts of Vilhelm Bjerknes, L.F. Richardson, and others who developed the primitive equations that today form the foundation of scientific meteorology (see the essay on General Circulation Models). Based on fundamental physics, this work was by definition interdisciplinary. Through the first half of the twentieth century, however, these efforts had scant impact on most of the people whose careers lay in the discipline of meteorology.
| Some hoped that climate, averaging over the
daily vagaries of weather, might be more amenable to scientific investigation.
They tried to understand changes on a timescale of decades or centuries,
and searched for regular climate cycles. While a few looked for possible
physical causes, it was more common for a climatologist to avoid such
speculation and carry out grinding numerical studies in hopes of pinning
down recurrences and perhaps predicting them. Analysis of large sets
of data turned up various plausible cycles, correlated perhaps with
variations in the number of sunspots. These correlations invariably
turned out to be spurious, further lowering the poor reputation of
climate change studies.
| The stagnant condition of climatology mirrored a deep belief that climate
itself was basically changeless. The careers of climatologists
their usefulness to society rested on the conviction that statistics
of the past could reliably describe future conditions. Their textbooks
defined "climate" as the long-term average of weather over
time, an intrinsically static concept. As one practitioner later complained,
"authoritative works on the climates of various regions were written
without allusion to the possibility of change, sometimes without mention
of the period to which the quoted observations referred."(8) In part this approach reflected a simple absence of data.
There were hardly any accurate records of daily temperatures, seasonal
rainfall, and the like that went back more than half a century or
so, even for the most civilized regions. The records were scantier
still for less-developed countries, and mere fragments for the three-quarters
of the world covered by water and ice. It seemed reasonable to assume
that the existing records did reflect the average weather over at
least the past few thousand years. After all, historical records back
to ancient times showed much the same mixtures of frosts and rains,
and the crops that went with them, in a given region.
| In fact, history gave only the crudest indications. But climatologists scarcely recognized
their ignorance, relying explicitly or implicitly on old assumptions
about the stability of nature. In other sciences like geology, experts
found good reason to maintain that natural processesoperated in a
gradual and uniform fashion. Ordinary people too mostly believed that
the natural world was self-regulating. If anything perturbed the atmosphere,
natural forces would automatically compensate and restore a self-sustaining
| To be sure, at least one immense climate
change was known and cried out for investigation the ice ages.
The stupendous advances and retreats of continental ice sheets were
worth study, not because scientists thought it was relevant to modern
civilization, but because they hoped to snatch the brass ring of prestige
by solving this notorious puzzle. Both professionals and amateurs
advanced a variety of simple explanations. Most of these amounted
to no more than vague but plausible-sounding arguments presented in
a few paragraphs. Each expert defended a personal theory, different
from anyone else's. The few scientists who attempted to write down
equations and calculate actual numbers for the effects managed to
prove little, except at best that their ideas were not wildly astray
by orders of magnitude.
| The most
acceptable explanations for the ice ages invoked geological upheavals
to block ocean currents or raise a mountain range against prevailing
winds. This was necessarily an interdisciplinary sort of theory. "It
is impossible to separate the geological from the meteorological,"
as one meteorologist remarked, "as the two are expressions of the
results of the same forces."(9) But the many pages that scientists wrote
amounted only to elaborate hand-waving, unsatisfactory within either
field. "I, for one," said the respected climatologist Hubert H. Lamb,
"must confess to having been bewildered and left quite pessimistic
by some discussions of climatic variation."(10) The very concept of "theory" became suspect in climate
| Theoretical models, whether of climate stability or ice-age changes,
were usually pursued as a minor sideline when they were not just ignored.
To study "the climate" of the planet as a whole was far less useful
and promising than to study "climates" region by region. There was
little point in attempting global calculations when all the premises
were uncertain and key data were lacking. Given the enormous obstacles
to reaching reliable results, and the prevailing view that the global
climate could not possibly change on a timescale that would matter
except to far future generations, what ambitious scientist could want
to devote years to the topic?
Meteorology and Geophysics (1940s-1950s)
| Yet it is the nature of scientists never to cease trying to explain
things. A few people worked to lift meteorology and climatology above
the traditional statistical approach. Helmut Landsberg's 1941 textbook
Physical Climatology and a 1944 Climatology textbook
written by two other meteorologists demonstrated how familiar physical
principles underlay the general features of global climate, and provided
a rallying-point for those who wanted to make the field truly scientific.
Many saw such studies as an exercise in pure mathematics, deliberately
remote from the fluctuations of actual weather. As one scientist recalled,
in the 1940s, "academic meteorologists would sometimes go out of their
way to disclaim any connection with forecasting an activity
of dubious scientific standing."(11)
| These textbooks came
into use during the Second World War as meteorology professors trained
thousands of meteorologists for the armed services. The training gave
a big boost to the few universities where scientific meteorology already
existed, and led to further expansion after the war. One example was
the young geology student Reid Bryson, who was picked up by the Air
Force and trained in weather forecasting. After the war he got a Ph.D.
in meteorology and, finding himself unwelcome in the geography department
at the University of Wisconsin, founded a one-man meteorology department
there. In 1962, the National Science Foundation gave him funds to
establish an important climate research center.(12)
Another example was Edward Lorenz, who had intended to be a mathematician
but was diverted into meteorology during the war, when the Army Air
Corps put him to work as a weather forecaster. Bryson and Lorenz were
among "a new breed of young Turks" who broke away from the tradition
of climatology as a mere handmaiden to forecasting. (At any rate,
that was how they saw themselves in retrospect.)(13)
|Leading the movement was a group at the University of Chicago,
where in 1942 Carl-Gustav Rossby had created a department of meteorology.
Rossby was a Swede who had learned mathematical physics in Stockholm
and spent two years at Vilhelm Bjerknes's institute in Bergen, Norway.
It was in Bergen that some of the key concepts of meteorology had
been discovered, notably the weather "front" (first recognized during
the First World War and named in accord with the concerns of the time).(14) With their improved understanding of weather patterns, Bjerknes's group had come to think of climate not so much in geographical terms as a matter of latitudes and locations, but in terms of typical weather systems. And if the pattern of weather systems in a region changed, didn't that mean a change of climate? It was a new way of looking at things, a "dynamical climatology" as one of the Bergen group put it.(14a)
|Rossby had come to the United
States in 1925 to work in the Weather Bureau. Outstanding not only
as a theorist but also as an entrepreneur and organizer, Rossby soon
left the somnolent Bureau. In 1928 he created the nation's
first professional meteorology program at the Massachusetts Institute
of Technology. After his move to Chicago he did still more, thanks to the ample wartime
support for training military meteorologists. The department trained
some 1,700 in one-year courses. Rossby also helped coordinate new
programs for graduate training of meteorologists at several other
|Support continued after the war, as the Cold
War and the expanding economy especially the rapid growth of
civil aviation raised the demand for meteorologists. The Chicago
group flourished. It was the first group anywhere to systematically
develop physical models of climate, sending out numerous students
to carry on the approach elsewhere. Meteorology began to gain a reputation
in the United States (as it already held in Europe) as a true scientific
discipline, and climatology followed. As Rossby remarked a few years
later, basic questions of climate change, such as storage of heat
in the oceans or the level of carbon dioxide gas in the atmosphere,
"mean a completely new class of questions... In these investigations
one is hardly interested in geographical distributions." Unlike the
traditional regional climatologists, his group looked at the entire
planet as a physical system.(16)
| War-trained young meteorologists also moved
into the U.S. Weather Bureau, where they found "the stuffiest outfit
you've ever seen," as a member of the research-oriented new generation
later recalled "deadly, deadly dull... a backward outfit."
An official report complained in 1953 that "the Bureau has displayed an arbitrary
and sometimes negative attitude toward new developments in meteorology
originating outside the Bureau." To be sure, inside the Bureau and still more outside it, meteorology was incorporating important new approaches such as weather radar, radiosondes to measure the upper atmosphere, and attention to the "air mass" analysis introduced by the Bergen school. And partly in response to the negative reports, conditions in the Bureau were improving rapidly. But as for climatology at the Bureau,
in 1957 another report described it as still nothing but a mere passive
"subsidiary to the task of forecasting."(17)
| Stagnation was unacceptable to those who
recalled the invaluable contributions of meteorology to military operations
during the war. The armed forces thought it no less important for
their postwar global operations, even if the Cold War stayed cold.
And if nuclear bombs exploded, meteorology would be especially vital
for tracking the deadly fallout. The Navy and Air Force in particular
continued to employ many hundreds of meteorologists. Besides, in keeping
with the new respect for science that they had learned during the
war, the armed forces supported a variety of academic researchers whose studies
might ultimately make forecasting better. As for climate, some of
these researchers held out the fascinating prospect of changing it
deliberately, perhaps as a weapon. The advances that meteorology was making toward solid
scientific understanding, combined with the lavish Cold War funding
for all science, made for a rapid expansion and professionalization
| It helped that the entire area of geophysics,
which included most of the fields relevant to climatology, was becoming
stronger and better organized. Since early in the century there had
been a few institutions, notably university institutes in Germany,
that embraced a wide enough range of studies to take the name "geophysical."
Already in 1919 an International Union of Geodesy and Geophysics was
founded, with separate sections for the different fields such as terrestrial
magnetism and oceanography. An American Geophysical Union was also
created in 1919 as an affiliate of the U.S. National Academy of Sciences
(it would not become an independent corporation with an international
membership until 1972). There followed a few other national societies
and journals such as the Zeitschrift für Geophysik.
Several German universities created formal programs teaching "Geophysik."
| As a founder of the International Union remarked, it was not so
much a union as a confederation.(18) The other early professional organizations
likewise brought little cohesion. Through the 1920s and 1930s, very
few institutions of any kind addressed geophysics in a broad sense.
Most individuals who might be called geophysicists did their work
within the confines of one or another single field such as geology
or meteorology. In the scientific investigation of climate change,
when I look over the more significant publications or at any
rate the ones I have used as references in the present study, found
in the bibliography a great
variety of books and journals turn up. The only ones that stood out
from the crowd in this period were the Quarterly Journal
and Memoirs of Britain's Royal Meteorological Society, which
together published 18% of the pre-1940 journal articles I have cited.
The runner-up was the Journal of Geology, with 9%.
| Beginning in the late 1940s, a more significant
number of inclusive institutions appeared. Institutes of geophysics
were created at American universities and under the Soviet Academy
of Sciences, along with funding organs like the Geophysics Research
Directorate of the U.S. Air Force. Another big boost came in 1957-58
when the International Geophysical Year pulled together thousands
of scientists from many nations. They interacted with one another
in committees that planned, and sometimes conducted, interdisciplinary
research projects involving a dozen different "geophysics" fields.(19)
Most of these fields were relevant to climatology.
| The annual meetings of the American Geophysical Union became a
rendezvous for divers fields, and for the same purpose the Union began
publishing a Journal of Geophysical Research (expanded from
the older and narrower Terrestrial Magnetism). However, for
the scattered scientists engaged with climate change, the best meeting-place
was Tellus, a "Quarterly Journal of Geophysics" that the
Swedish Geophysical Society created in 1949. The journal's importance
is evident in the list of papers that found their way into the bibliography
that I compiled in my research for this study. During the decades
1940-1960, Tellus published some 20% of these papers, more
than any other journal. (The runners-up were the American interdisciplinary
journal Science, with 15%, the Journal of Meteorology,
with 10%, and the Quarterly Journal of the Royal Meteorological
Society, with 5%. The Journal of Geophysical Research
accounted for only 3%, about equal to the American Journal of
Science and the Journal of Geology.)
| Some two-thirds of these papers were written
in the United States a much higher fraction than for earlier
years.(20) This was partly because the rest of
the civilized world spent the 1950s recovering from the war's devastation.
It was still more because generous U.S. government support for geophysical
research, based on Second World War successes, did not falter even
when memories of the war faded. For the global military and economic
concerns of the Cold War put geophysics near the head of the line
for research funds.
| In geophysics as in all the sciences of the 20th century, expansion
raised a risk of further fragmentation. Early in the century, so little
had been known about anything in geophysics that the best scientists
had broad knowledge of many aspects of the subject. For example, between
the world wars Harald Sverdrup published research on the circulation
of the atmosphere, the circulation of the oceans, glaciers, geomagnetism,
and the tides, not to mention the ethnology of Siberian tribes. A
few decades later, when knowledge had grown deeper and techniques
had become more esoteric, hardly anyone could do significant work
in more than one or two fields.
| It was getting ever
tougher for a scientist to become expert in a second field of knowledge.
Few now attempted it, for the diversion of energy risked your career.
"Entering a new field with a degree in another is not unlike Lewis
and Clark walking into the camp of the [Native American] Mandans,"
remarked Jack Eddy, a solar physicist who took up climate studies
in the 1970s. "You are not one of them... Your degree means nothing
and your name is not recognized. You have to learn it all from scratch,
earn their respect, and learn a lot on your own."(21) Some of the most important discoveries came from people
like Eddy, who did spend years in a foreign camp. Another example
was Nick Shackleton, who after studying physics (essential for laboratory
work measuring isotopes) and mathematics (necessary for analysis of
time series) became part of a research group that analyzed pollen
in a university botany department. The eventual result was landmark work on the timing and nature of the Ice Ages.(22) Such combinations, however valuable, were uncommon.
| The problem was particularly
severe for climate studies. There had never been a community of people
working on climate change. There were only individuals with one or
another interest who might turn their attention to some aspect of
the question, usually just for a year or so before returning to other
topics. An astrophysicist studying changes in solar energy, a geochemist
studying the movements of radioactive carbon, and a meteorologist
studying the global circulation of winds, had little knowledge and
expertise in common. Even within each of these fields, specialization
often separated people who might have had something to teach one another.
They were unlikely to meet at a scientific conference, read the same
journals, or even know of one another's existence. Nor did theorists
interact regularly with people who worked out in the field. As one
climate expert remarked, "lack of interest has all too often characterized
the attitude of physical scientists to the masses of information produced
by botanists examining pollen deposits and the data turned out by
geologists, glaciologists, entomologists, and others. These types
of literature have never been part of their regular diet."(23)
| To make communication still harder, different fields attracted
different kinds of people. If you went into the office of a statistical
climatologist, you could expect to find ranges of well-organized shelves
and drawers stacked with papers bearing neat columns of figures. In
later years the stacks would hold computer printouts, the fruit of
countless hours spent coding programs. The climatologist was probably
the kind of person who, as a boy, had set up his own home weather
station and meticulously recorded daily wind speed and precipitation,
year after year. Go into the office of an oceanographer, and you were
more likely to find a jumble of curiosities from the shores of the
seven seas. You could hear adventure stories, like Maurice Ewing's
tale of how he was washed overboard and escaped drowning by a hair.
Oceanographers tended to be salty types, accustomed to long voyages
far from the comforts of home, outspoken and sometimes self-centered.(24)
| These differences went along with divergence in matters as fundamental
as the sorts of data people acquired and used. The economic importance
of weather forecasting meant that climatologists could draw on a century-old
and world-wide network of weather stations. "Meteorologists use mainly
standard observations made by technicians," as an oceanographer recently
remarked, "while the much smaller number of oceanographers usually
make their own measurements from a small number of research ships,"
often with instruments they had built for themselves.(25*) The climatologist's weather, constructed
from a million numbers, was something entirely different from the
oceanographer's weather a horizontal blast of sleet or a warm
relentless trade wind.
| On top of social and perceptual gaps were technical
divergences. As one expert remarked in 1961, "The fact that there
are so many disciplines involved, as for instance meteorology, oceanography,
geography, hydrology, geology and glaciology, plant ecology and vegetation
history to mention only some has made it impossible
to work... with common and well established definitions and methods."
Scientists in different fields might use standards so different, he
said, "that comparisons between the results have been hardly possible."(26)
| Recognizing the problem, meteorologists made significant efforts to recruit students from various fields of the physical sciences and to initiate interdisciplinary work. Physics, chemistry, and mathematics played an increasing role in what was coming to be called the "atmospheric sciences." A Journal of the Atmospheric Sciences had been founded already in 1944. As one example of how the process went still farther, in 1961 Chicago's pioneering Department of Meteorology merged with the Department of Geology to form a Department of the Geophysical Sciences. Yet up to this point the discipline of meteorology itself had remained to a large degree divided. The climatologists
who continued to gather empirical weather statistics and analyze them were intellectually
remote from the academic theorists, who worked up mathematical models based
on physical principles rather than observations. Both often looked
down on practical forecasters, who in turn had little faith in the
professors' abstractions. Among all three types of meteorologist,
very few worked on questions of long-term climate change.(27)
Confronting Climate Change (1960s-1970s)
| Fragmentation was becoming
intolerable by the 1960s. More than half a century of reliable temperature
measurements were now in hand from around the world, and they showed
that global temperatures had risen. Meanwhile observations of the
climbing level of carbon dioxide in the atmosphere brought a threat
of serious future changes. Besides, scholarly studies that extended
the climate record far into the historical past were revealing large
climate shifts. Most notable was evidence of a century or so of exceptional
warmth in parts of medieval Europe and the North Atlantic (this was
when the Vikings settled Greenland). There had followed winters so
harsh that early modern times could be called a “Little Ice
Age” — at least in some regions. Records were spotty,
at best, for the world outside the North Atlantic region, but for many places evidence was emerging of anomalies such as centuries of prolonged
|Painful experience drove the point home. One notorious case was
the experience of firms that contracted to build dams in central Africa
in the 1950s, and consulted with climatologists about the largest
floods that could be expected according to past statistics. The firms
then began construction, only to suffer "fifty-year floods" in each
of the next three years.(28)
Such experiences pulled the props out from the traditional climatology.
The laboriously compiled tables of past statistics were plainly not
reliable guides to the future.(29)
| This unhappy fact was not easily accepted. As late as 1968, a textbook on
Climatology and the World's Climate said baldly, "The subject
of climatic change is not given specific treatment in this book."(30*) Applied climatologists
continued to base their projections of the future on their hoards
of old statistics, simply for lack of anything better. Their work
was in fact becoming increasingly useful. As the data base grew and
methods of analysis expanded, climatological studies brought a better
understanding of how warm spells affected crops, what factors contributed
to floods, and so forth.(31) Nevertheless, during the 1960s more
and more scientists realized that climate predictions could not rely
only on past observations, but must use physical models and calculations.
Traditionally "climate" had been defined as the weather in a region
averaged over a period. For example, in 1935 the International Meteorological
Organization had adopted the years 1901-1930 as the "climatic normal
period." A moving thirty-year span became accepted as a baseline for predictions of future climates. But experts increasingly saw that this practice, however necessary to provide answers to pressing questions, could be misleading. The first three decades of the century turned out to have weather far from what was "normal" in later
decades. Indeed there might be no such thing as a set of decades
that could define a "normal" climate. Climate was something that changed
continually under the impact of physical forces.(32*)
| The new thinking was
displayed in full at a 1965 symposium held in Boulder, Colorado on
"Causes of Climate Change." While the meeting made little special
impression at the time, in retrospect it was a landmark. For it deliberately
brought together scientists from a fantastic variety of fields, experts
in everything from volcanoes to sunspots. Presiding over the meeting
was an oceanographer, Roger Revelle. Lectures and roundtable discussions
were full of spirited debate as rival theories clashed, and Revelle
needed all his exceptional leadership skills to keep the meeting on
track.(33) Convened mainly to discuss explanations
of the ice ages, the conference featured a burst of new ideas about
physical mechanisms that could bring surprisingly rapid climate shifts.
In his formal summary of the discussions, the respected climatologist
Murray Mitchell reported that our "comparatively amicable interlude"
of warmth might give way to another ice age, and sooner than had been
supposed. That foreboding possibility required scientists to understand
the causes of climate change, he said, and to suggest how we might
use technology to intervene.(34)
| This sort of thinking spread widely in the
early 1970s. A spate of devastating droughts and other weather disasters
showed that climate was grossly unreliable. With the alarming news
came warnings that the near future might see still worse whether
drastic cooling or global warming thanks to pollution of the
atmosphere following the explosive growth of human population and
industry. This was an active and even aggressive view of climate in
relation to humanity; it called for aggressive research. "The old
descriptive climatology," an authority remarked in 1975, "concerned
mainly with statistics and verbal interpretation of them, is evolving
into a new mathematical, or dynamic, climatology with predictive capability
based on physical-mathematical processes rather than extrapolation
of statistical measures."(35)
| That required a new kind of research community,
more closely linked to other fields and other kinds of science. This
was happening in all the Earth sciences. The traditional observational
geologist, out in the field with his high-laced engineer's boots and
rock hammer, had to make room for the investigator who saw rocks mainly
in her laboratory, or perhaps only in pages of equations and calculations.
Old-school geologists grumbled that the move to laboratory and theoretical
geophysics took people away from a personal confrontation with nature
in all its complexity and grandeur. The same filtering of experience
was spreading in climate studies. Most scientists with something to
contribute focused on technical problems peculiar to their own specialty.
How do aerosols make clouds? How can you get a computer model to show
the annual cycle of the seasons? What was the pattern of ancient glacial
cycles? Those who did attack broader questions head-on seemed out
of date. Some continued to propose simple hand-waving models with
physical explanations for climate change (especially the ice ages).
But the different explanations were patently speculative, infected
by special pleading and mostly incompatible with one another.
| Scientists were more skeptical than ever of the traditional approach,
in which each expert championed a favorite hypothesis about some particular
cause for climate change blaming every shift on variations
in, say, dust from volcanoes or the Sun's luminosity. It seemed
likely that many factors contributed together. Meanwhile the factors
were interacting with one another. And on top of these external influences,
it appeared that some part of climate change was self-sustaining,
through feedbacks involving the atmosphere, ice sheets, and ocean
circulation. "It is now generally accepted," wrote one authority in
1969, "that most climatic changes... are to be attributed to a complex
| The shortcomings of
the old single-cause approach were especially visible to those who
tried to craft computer models of climate. A plausible model
could not be constructed, let alone be checked against real-world
data, without information about a great many different kinds of things.
It became painfully clear that scientists in the various fields needed
one another. Specialists began to interact more closely, drawing on
one another's findings or, equally valuable, challenging them. It was the stringent requirements of numerical computation, more than anything else, that forced the isolated communities of meteorology—empirical climatologists with their statistics, weather forecasters with their practical intuition, academic scientists with their theories and equations—to communicate with one another in a common enterprise, and beyond that to talk with other scientists of every stripe.
Means of Communication (1970s-1980s)
| The changes in meteorology and geophysics were typical
of a movement in all the sciences. For more than a century many fields
of science had narrowed their perspective to simplified cases, pursuing
solutions as compact and elegant as Newton's equations. Subjects as
far afield as sociology were swayed by what some began to call "physics
envy." Only a few scientists insisted on looking instead at whole
systems with all their complexities. That approach began to spread
in various fields during the postwar years, and a growth spurt in
the 1970s brought into prominence what was coming to be called "holistic"
investigation. In biology, for example, different disciplines were
talking to one another within the increasingly popular field of ecology.
This was timely, for scientists were increasingly concerned that biological
communities were yet another feature that interacted intimately with
the planet's climate. Some specialists had long been aware of such
interactions most notably in oceanography, which was explicitly
a union of physical oceanography and biological oceanography (if only
because the researchers had to bunk alongside one another on their
voyages). Now all of geophysics was coming to be seen as part of a
larger field, the "Earth sciences."
| In the fields relating to climate, as in other sciences, textbooks
and review articles in ever growing numbers summarized the recent
findings of this or that specialty for the benefit of outsiders. More
and more conferences were held with the aim of bringing together anywhere
from a dozen to several hundred people from different but relevant
fields. Most scientists, however, continued to call themselves oceanographers
or computer scientists or paleobotanists or whatever. Not many would
identify themselves as primarily a... a what? A "climate change scientist?"
There was not even an accepted term to describe the non-discipline.
The typical landmarks for the creation of a discipline, such as departments
at universities or a scientific society named for the subject, never
came. The key elements for any profession socialization and
employment, which for scientists usually meant training as a graduate
student and employment as a professor were largely carried out
within traditional disciplines like meteorology or oceanography, or in more broadly defined fields such as atmospheric sciences in which climate change was included only as one element among many.
| In 1977, one landmark for the recognition
and coalescence of a scientific discipline did come with the foundation
of a dedicated journal, Climatic Change. But unlike many
new journals, this one did not in fact launch itself as the flagship
of a new discipline. Its explicit policy was to publish papers that
were mainly interdisciplinary, such as explorations of the consequences
that global warming might have on ecosystems. The founding editor, Stephen Schneider, said later that he took up the task "to spite my institute director," who had warned him that pursuing interdisciplinary work would hurt his career. For many scientists believed that solid research could be done only within the strict framework of a traditional discipline.(37*)
|Most scientific papers on climate change itself continued
to be published in journals dedicated to a particular established discipline, like the
meteorologists' Journal of the Atmospheric Sciences or the
paleontologists' Quaternary Research. But key papers were
also welcomed by the two great interdisciplinary scientific journals,
Science and Nature, where specialists in every field
would see them. (In my bibliography for 1960-1980, JAS published
10% of all papers and Quat. Res. 7.5%. Science published
23%, if one includes a few news articles, and Nature 10%.
Tellus was down to 5%, equal to the J. Geophysical Research,
followed by the Journal of Applied Meteorology at 4%. The
Quart. J. Royal Met. Soc. fell to 2.5%.)
| To a degree, climate science remained "a scientific backwater,"
as one of its leading figures recalled decades later. "There is little
question," he claimed, "that the best science students traditionally
went into physics, math and, more recently, computer science."(38*) The study of climate was not a field where you could win
a Nobel Prize or a million-dollar patent. You were not likely to win
great public fame, nor great respect from scientists in fields where
discoveries were more fundamental and more certain. In the mid 1970s,
it would have been hard to find a hundred scientists with high ability
and consistent dedication to solving the puzzles of climate change.
Now as before, many of the most important new findings on climate
came from people whose main work lay in other fields, from air pollution
to space science, as temporary detours from their main concerns.
| Coordination and communication nevertheless improved as climate science was
swept along by changes in the sciences as a whole. During the 1960s
and 1970s, governments doubled and redoubled the budgets for every
field of research, and geophysics got its share. Scientists concerned
about climate change worked to get governmental and international
agencies to organize their diverse research efforts through a central
office or committee. It took decades of failures and false starts,
but by the end of the 1970s, they managed to put together a number
of ambitious climate programs. While still lacking central coordination,
each of the programs embraced a variety of fields. In particular,
the United States established a National Oceanic and Atmospheric Administration
that united oceanography with meteorology in a formal institutional
sense, even if the usual bureaucratic barriers remained between divisions.
Meanwhile within NASA, where designing satellites to observe the Earth
from space gave a push to broader views, some worked deliberately
to break down disciplinary boundaries and create an “Earth System
in diverse fields with an interest in climate change found themselves
meeting in the various committees and panels that reviewed and directed
such programs. The process was officially capped in the mid 1980s
by the creation of an "International Geosphere-Biosphere Program,"
which coordinated work across so many disciplinary boundaries that
some began to worry that there were now too many cooks in the kitchen.
| The researchers
in such programs no longer spoke of studying "climates" in the old
sense of regional weather patterns, but of "the climate system" of
the whole planet, involving everything from minerals to microbes.
This was a fundamentally novel approach. We could call it a new "paradigm,"
in the word's basic sense of a pattern (like the amo, amas, amat
of Latin grammar texts) that scientists used to structure their thinking
as they attacked their research problems.(39*) Many things contributed to the new
approach, but nothing so much as the computer studies that began producing
plausible climate models during the 1970s. The models spoke eloquently
of a global system in their basic concepts, and showed it memorably
in their computed maps of weather patterns.(40)
| For studying a system with features dispersed among many specialties,
the solution was collaboration. This trend was strong in all the sciences,
as research problems spanned ever more complexities. Scientists with
different types of expertise exchanged ideas and data, or worked directly
together for months if not years. Universities and other institutions,
braced by ample funding, increasingly encouraged coalitions of research
groups in a variety of fields. Specialists in the ionosphere, the
Earth's interior, ocean currents, even biology, found themselves sharing
the same funding agencies, institutions, and perhaps buildings. Sessions
bringing together different specialists on one or another climate
topic multiplied at meetings of the American Geophysical
Union and similar organizations. It became increasingly common to
hold entire workshops, meetings or conferences devoted to a particular
|Perhaps most important, every scientist read Science and
Nature, which competed with one another for outstanding papers
in all fields, including those connected with climate change. Both
these weekly journal-magazines also published expert reviews and commentaries,
and Science published staff-written news articles, keeping
everyone up-to-date on selected developments outside their own field.
(Of the papers in my bibliography for 1981-2000, Nature and
Science tied with 25% each, including commentary and news
articles, followed by the J. Geophysical Research with 15%
and Climatic Change with 7%. Tellus fell below 1%.
The journal EOS: Transactions of the American Geophysical Union,
publishing a mixture of short scientific reviews and news articles,
came in at 4%. A variety of new review journals titled Advances
in... and Reviews of... collectively contributed another
4%.) Climate science was now mainstream, with new developments covered thoroughly not only in Science and Nature but in the popular press and, in the 2000s, on the internet. The number of scientific papers in the field soared exponentially: as a fraction of all scientific publications, papers on climate change doubled every five years from the 1980s into the 2000s.(40a)
|An especially powerful mechanism
for cooperation was the formation of projects to address particular
interdisciplinary topics. For example, specialists
in computer modeling got together with paleontologists to test whether
the models were robust enough to simulate a climate different from
the present one. The Cooperative Holocene Mapping Project (COHMAP)
was conceived in the late 1970s at the University of Wisconsin, where
Reid Bryson had established a group that reconstructed past climates
from fossil pollen and the like. The project expanded through the
1980s, recruiting a variety of domestic and foreign collaborators.
Some of them would devote most of their research careers to the project.
Typical of such projects, all the collaborators would convene from
time to time in large assemblies. But a few leaders would also gather
in smaller meetings, "often hosted in home settings where conversations
were unhurried and brainstorming was lively." Computer models
confronted paleontological data in a continual dialogue, each discrepancy
forcing one side or the other, or both, to go back and do better.
(Ultimately the modelers produced a good simulation of the climate
maps that the paleontologists developed for a warm period 8,000 years
|COHMAP was only one example of many interdisciplinary projects driven by the demands of modelers, who sought empirical data on a scale to match the floods of numbers gushing from their computers. Large modeling groups in the United States, Great Britain, Germany, and elsewhere, pursuing empirical data to validate and correct their work, inspired costly projects in specialties ranging from satellite instrumentation to oceanography to forestry. Traditional climatology with its vast archives of data helped with its own major projects of analysis and synthesis. For other international projects see the essay on International
Cooperation and Integration (1990s- )
| Projects with multiple contributors were becoming common in all the sciences, a consequence of the increasing specialization within each discipline plus increasing value in making connections between disciplines. Versatile scientists like Sverdrup — or as another example Bert Bolin, who had mastered fields ranging from the mathematics of atmospheric circulation to the geochemistry of CO2 — were a vanishing breed. Nearly all the papers
written before 1940 in my bibliography were published under a single
name; only a few were the work of two authors. But of papers written
in the 1980s, fewer than half had one author. Many of the rest had
more than two, and a paper listing, say, seven authors was no longer
extraordinary. Large projects were represented by, for example, a
1989 paper with 20 authors from 13 different institutions in seven
countries. The trend continued through the 1990s, as single-author
papers became increasingly rare.(41*)
|None of this entirely solved the problem of
fragmentation. Into the 21st century there remained entire communities
of experts, for example water resource managers, who still treated
climate as something that fluctuated only within the unchanging boundaries
described by historical statistics. And the more the research enterprise
grew, the more scientists would need to specialize. Moreover, the imperatives
of administration would always maintain boundaries between academic
disciplines, and between the government agencies and organizations
that supported them. However, by now everyone was keenly aware of
the dangers of fragmentation and strove for better coordination. For
many kinds of research, climatologists, geochemists, meteorologists,
botanists, and so forth added to their disciplinary category a second
form of identification an all-embracing name reflecting a new
social orientation and holistic approach "environmental scientist."They
were borrowing the luster of a word that had come to stand for a widely
admired attitude, with concerns embracing the Earth as a whole. (42*)
| Meanwhile, some scientists altered even their primary professional
identification. By the end of the century the issue of climate change
had become important and prestigious enough to stand on its own.
Certain scientists who once might have called themselves, say, meteorologists
or oceanographers, were now designated "climate scientists."(43)
There was still no specific professional organization or other institutional
framework to support "climate science" as an independent discipline. But that did not matter much in the new order of holistic interdisciplinary
|The internet helped bring people closer together. As soon as you
heard about a paper in any journal on any subject, you could now find
it online with ease, sometimes months before its formal publication.
E-mail made it far easier to argue out ideas and exchange data, with
as many people listening to the conversation as you liked. A few climate
scientists went on to maintain blogs (notably realclimate.org),
encouraging a still more universal interchange.
|Still, the most important mechanism was the one that had sustained
scientific communities for centuries—you went to meetings and
talked with people. As one scientist described the system, "Most
sucessful scientists develop networks of 'trusted' sources—people
you know and get along with, but who are specialists in different
areas... and who you can just call up and ask for the bottom line.
They can point you directly to the key papers related to your question
or give you the unofficial 'buzz' about some new high profile paper."(44)
|For climate scientists, the
process of meetings and discussion went a long step farther when
the world’s governments demanded a formal advisory procedure.
The resulting Intergovernmental Panel on Climate Change (IPCC) was
not really a single panel, but a nexus of uncounted international
workshops, exchanges of draft reports, and arguments among individuals,
all devoted to producing a single authoritative assessment roughly every
half-dozen years. From the 1990s on, the process engaged every significant
climate scientist in the world (and many of the insignificant ones).
At the time of its 2007 assessment, the IPCC process had grown to
include 157 authors plus some 600 reviewers in the geophysical sciences, giving a rough idea
of the size of the scientific community on which the world's policy-makers
now depended for crucial advice.(45)
|In some fields the IPCC process
became the central locus for arguments and conclusions.(46)
This went farthest among computer modelers, whose efforts increasingly
focused on cooperative projects to produce results for the IPCC assessments.
When climate modelers studied the details of each factor that went
into their calculations, and when they sought large sets of data to
check the validity of their results, they had to interact with every
specialty that had anything to say about climate change. Every group
felt an intense pressure to come up with answers, as demanded by the
world's governments and by their own rising anxieties about the future.
In countless grueling exchanges of ideas and data, the experts in
each field hammered out agreements on precisely what they could, or
could not, say with confidence about each scientific question. Their
projections of future climate, and the IPCC reports in general, were
thus the output of a great engine of interdisciplinary research. In
the world of science this was a social mechanism altogether unprecedented
in its size, scope, complexity and efficiency — as well as in
its importance for future policy.
|By the early 21st century, climate scientists had arrived at conclusions that carried profound implications for economic policy and even modes of living. In consequence, governments and the public began to give close attention to the field. Funding continued to be stronger than for many other fields, addressing the the growing anxiety among not only scientists but a large part of the public, and the need for costly satellites, computers, and expeditions by land and sea. However, the gravity of the issue awakened political polarization, bringing severe pressures. Officials and the media demanded simple answers to complex questions.Worse, some politicians and many organizations and individuals attacked not only scientific theories and data, but the climate science community itself as dishonest and corrupt. Vilification, death threats, and legal and illegal harassment deeply affected a few prominent scientists and discouraged others. It even became necessary to create a Climate Science Legal Defense Fund. Some scientists responded with their own political activism, while the community as a whole pressed on with its research.
|In 2015 a survey identified a climate scientist community with roughly 4,000 members (of whom one-third had been authors or reviewers of the most recent report by the Intergovernmental Panel on Climate Change). About a quarter of the respondents worked in the United States and Canada, with Germany second, the United Kingdom third, and fewer than 4% in any other country. Six-tenths worked in academia and most of the rest in non-academic publicly funded research institutions. Nearly all of them were convinced that the climate was changing because of human influences, and believed that if nothing was done about it, the world faced a high "potential for catastrophe" within the next 50 years.(47)
Simple Models of Climate
Reflections on the Scientific Process
1. Weyl (1968), p. 60.
2. For civil engineers demanding more data, see Genuth (1987), p. 244.
3. United States (1953), p. 24.
4. H. Lamb quoted in Alexander
(1974), p. 90.
5. For 19th-century origins of climatology, see Nebeker (1995), pp. 24-25; on the empiricism of the field, Eady (1957), quote p. 113, emphasis in original.
6. Cressman (1996), pp.
382-85; "know little:" Stringer (1972), p. xii.
7. Accuracy not improved: Mason
(1957), p. 175, see p. 183; Koelsch
(1996); College degrees: Byers (1976),
p.1343. "Blues": George Platzman to Jule Charney, 18 June 1950, Box 14:451,
Charney Papers, Massachusetts Institute of Technology Archives, Cambridge,
MA. On the low professional status of US meteorology see Harper
8. Lamb (1959), p. 299.
9. Napier Shaw in discussion of Harmer (1925), p. 258.
10. Lamb (1959), p. 4.
11. Landsberg (1941, rev.
ed. 1947, 1960), see the preface, p. iii; On the book's importance:
Taba (1991), p. 97; Haurwitz and Austin's Climatology
(and also Rossby) are noted by Smagorinsky (1991),
p. 30; "academic... dubious": Sutcliffe (1963),
p. 277. BACK
12. Bryson (1967), and
personal communication, 2002.
13. Koelsch (1996); "Turks":
Smagorinsky (1991), p. 31; Nebeker
(1995), ch. 9.
14. Friedman (1989).
14a. Heymann (2010). BACK
15. Here and below I am grateful for the use in draft of Doel (2003). Rossby: Fleming (2016).
16. Byers (1959);
Rossby (1959), quote p. 16. Reputation: Harper
17. "Stuffiest": Athelstan Spilhaus, interview by Ron Doel,
November 1989, AIP; see also Joseph Smagorinsky, "Climate's scientific maturity," in Baer et al. (1991), pp. 29-35, 31; "arbitrary:" United States (1953), p. 36, see pp. 3-4; "subsidiary:" National Academy of Sciences (1957).
18. L.A. Bauer quoted in Good
(2000), p. 286, q.v. for this topic in general.
19. Doel (1997); Doel (1998).
20. My rough count from a sample.
21. J.A. Eddy, interview by Weart, April 1999, AIP, p. 4.
22. Shackleton (2003).
23. Lamb (1997), p. 200.
24. For strains on deep-ocean oceanographers, see Mukerji (1989), pp. 66-73; Ewing: Wertenbaker (1974), pp. 130-33.
25. Indeed "meteorology and oceanography are practiced in a
very different manner and by two largely non-overlapping groups of people... there are still
relatively few meteorologists who have more than a superficial knowledge of the ocean, and vice
versa." Charnock (1998), p. 623.
26. Wallén (1963), p.
27. Nebeker (1995), pp. 1-2.
28. Floods: Lamb (1997),
p.178, see passim for historical work.
29. Lamb (1959); Lamb (1966), p. ix.
30. Rumney (1968), p. vii; in
another widely used text, a chapter on climate change first appeared, with a new author, in 1980
(the fifth edition): Trewartha and Horn (1980).
31. Cressman (1996).
32. I have seen only one explicit statement about this at the time
("we are faced with an initial difficulty of definition which has far-reaching consequences..."),
Robinson (1971), p. 12; similarly but implicitly, Barrett and Landsberg (1975), p. 18; for the history, see Lamb (1995), pp. 10-11.
33. Mitchell (1968), p. iii-iv.
34. Mitchell, "Concluding Remarks," drawing on the remarks by
Roger Revelle, in Mitchell (1968), p. 157.
35. Barrett and Landsberg
(1975), p. 76; see Lamb (1995), pp. 12-14.
36. Lamb (1969), p. 178.
37. Policy: Schneider (1991). Schneider (2009), pp. 75-76. N.b., in 1983
the Journal of Applied Meteorology became the Journal of
Climate and Applied Meteorology, absorbed in 1988 into the Journal
of Climate, which had begun in 1986. BACK
38. The claim was made to warn policy-makers about the
unreliability of climate predictions, but it is plausible. Richard Lindzen, Testimony before the
Senate Environment and Public Works Committee, May 2, 2001, available as appendix to United States Congress (107:1) (2001).
38a. Conway (2008).
39. The term has multiple meanings in the classic
Kuhn (1962); for this particular usage, see Weart (1983). BACK
40. Articles mentioning "climate change" or "global warming" in title or abstract; the number is normalized for the overall (rapid, but slower) increase of scientific publication in general. Goodall (2008), p. 411. BACK
40a. Edwards (2001). BACK
40b. Webb (2007),
quote p. 107; see also comments in this volume by Kutzbach, p. 224, and
Sandy P. Harrison, p. 168. BACK
41. To be precise, 92 percent were single-authored pre-1940,
and 58 percent during 1980-1988. Seven authors: e.g., Hansen et al.
(1981); Dansgaard et al. (1982); 20 authors: Cess et al. (1989); multiple authorship in the 1990s is plain from
scanning the references in IPCC (2001).
42. Water resource managers: Milly
et al. (2008). Doel (1997);
Earth scientists had already begun to speak of "environmental sciences"
as they coordinated Cold War research in the 1950s, Doel
43. Richard Lindzen, Testimony before the Senate Environment
and Public Works Committee, May 2, 2001, available as appendix to United States Congress (107:1) (2001).
44. Gavin Schmidt, "AGU Hangover,"
posted Dec. 24, 2006. BACK
45. IPCC (2007b).
46. For example, in studying effects on
climate of atmospheric chemistry and aerosols, from the mid 1990s the
main advances were consolidated in international workshops under IPCC
auspices. Le Treut et al. (2007),
p. 109. BACK
47. Bray and von Storch (2016), pp. 4, 8-11, 108. BACK
© 2003-2017 Spencer Weart & American Institute of Physics