Global Warming: Real, but NOT Caused by Humans
I offer a scientific interpretation of the exact same data on carbon dioxide
levels. The results do conclude that levels of carbon dioxide are increasing,
but that the increases are not driven by the influence of humanity and the Industrial
Revolution, but are the result of a natural rhythm in Earth's history between
ice ages and warming trends. The climatological record from ice sheets and deep
ocea core analysis confirms these cycles. The question here is whether humans
are the prime players or not, and whether our carbon dioxide emissions from
cars and industries can lead to a Doomsday for the planet, or merely to warmer
weather to which we must prepare for. Please look this over and make your own
judgment on the issue of Global Warming. When you are presented with two sides
to an argument, complete with relevant data to interpret, then indeed you are
better educated, more qualified to speak on the topic, and entitled to an opinion
which has evidence to which you can turn to back up your debate stand.
Global Warming: The Origin and Nature of the Alleged Scientific Consensus
Richard S. Lindzen
Richard S. Lindzen is the Alfred P. Sloan Professor of Meteorology at the Massachusetts
Institute of Technology.
Most of the literate world today regards "global warming'' as both real
and dangerous. Indeed, the diplomatic activity concerning warming might lead
one to believe that it is the major crisis confronting mankind. The June 1992
Earth Summit in Rio de Janeiro, Brazil, focused on international agreements
to deal with that threat, and the heads of state from dozens of countries attended.
I must state at the outset, that, as a scientist, I can find no substantive
basis for the warming scenarios being popularly described. Moreover, according
to many studies I have read by economists, agronomists, and hydrologists, there
would be little difficulty adapting to such warming if it were to occur. Such
was also the conclusion of the recent National Research Council's report on
adapting to global change. Many aspects of the catastrophic scenario have already
been largely discounted by the scientific community. For example, fears of massive
sea-level increases accompanied many of the early discussions of global warming,
but those estimates have been steadily reduced by orders of magnitude, and now
it is widely agreed that even the potential contribution of warming to sea-level
rise would be swamped by other more important factors.
To show why I assert that there is no substantive basis for predictions of
sizeable global warming due to observed increases in minor greenhouse gases
such as carbon dioxide, methane, and chlorofluorocarbons, I shall briefly review
the science associated with those predictions.
Summary of Scientific Issues
Before even considering "greenhouse theory,'' it may be helpful to begin
with the issue that is almost always taken as a given--that carbon dioxide will
inevitably increase to values double and even quadruple present values. Evidence
from the analysis of ice cores and after 1958 from direct atmospheric sampling
shows that the amount of carbon dioxide in the air has been increasing since
1800. Before 1800 the density was about 275 parts per million by volume. Today
it is about 355 parts per million by volume. The increase is generally believed
to be due to the combination of increased burning of fossil fuels and before
1905 to deforestation. The total source is estimated to have been increasing
exponentially at least until 1973. From 1973 until 1990 the rate of increase
has been much slower, however. About half the production of carbon dioxide has
appeared in the atmosphere.
Predicting what will happen to carbon dioxide over the next century is a rather
uncertain matter. By assuming a shift toward the increased use of coal, rapid
advances in the third world's standard of living, large population increases,
and a reduction in nuclear and other nonfossil fuels, one can generate an emissions
scenario that will lead to a doubling of carbon dioxide by 2030--if one uses
a particular model for the chemical response to carbon dioxide emissions. The
Intergovernmental Panel on Climate Change Working Group I's model referred to
that as the "business as usual'' scenario. As it turns out, the chemical
model used was inconsistent with the past century's record; it would have predicted
that we would already have about 400 parts per million by volume. An improved
model developed at the Max Planck Institute in Hamburg shows that even the "business
as usual'' scenario does not double carbon dioxide by the year 2100. It seems
unlikely moreover that the indefinite future of energy belongs to coal. I also
find it difficult to believe that technology will not lead to improved nuclear
reactors within fifty years.
Nevertheless, we have already seen a significant increase in carbon dioxide
that has been accompanied by increases in other minor greenhouse gases such
as methane and chlorofluorocarbons. Indeed, in terms of greenhouse potential,
we have had the equivalent of a 50 percent increase in carbon dioxide over the
past century. The effects of those increases are certainly worth studying--quite
independent of any uncertain future scenarios.
The Greenhouse Effect.
The crude idea in the common popular presentation of the greenhouse effect
is that the atmosphere is transparent to sunlight (apart from the very significant
reflectivity of both clouds and the surface), which heats the Earth's surface.
The surface offsets that heating by radiating in the infrared. The infrared
radiation increases with increasing surface temperature, and the temperature
adjusts until balance is achieved. If the atmosphere were also transparent to
infrared radiation, the infrared radiation produced by an average surface temperature
of minus eighteen degrees centigrade would balance the incoming solar radiation
(less that amount reflected back to space by clouds). The atmosphere is not
transparent in the infrared, however. So the Earth must heat up somewhat more
to deliver the same flux of infrared radiation to space. That is what is called
the greenhouse effect.
The fact that the Earth's average surface temperature is fifteen degrees centigrade
rather than minus eighteen degrees centigrade is attributed to that effect.
The main absorbers of infrared in the atmosphere are water vapor and clouds.
Even if all other greenhouse gases (such as carbon dioxide and methane) were
to disappear, we would still be left with over 98 percent of the current greenhouse
effect. Nevertheless, it is presumed that increases in carbon dioxide and other
minor greenhouse gases will lead to significant increases in temperature. As
we have seen, carbon dioxide is increasing. So are other minor greenhouse gases.
A widely held but questionable contention is that those increases will continue
along the path they have followed for the past century.
The simple picture of the greenhouse mechanism is seriously oversimplified.
Many of us were taught in elementary school that heat is transported by radiation,
convection, and conduction. The above representation only refers to radiative
transfer. As it turns out, if there were only radiative heat transfer, the greenhouse
effect would warm the Earth to about seventy-seven degrees centigrade rather
than to fifteen degrees centigrade. In fact, the greenhouse effect is only about
25 percent of what it would be in a pure radiative situation. The reason for
this is the presence of convection (heat transport by air motions), which bypasses
much of the radiative absorption.
What is really going on is schematically illustrated in Figure 1. The surface
of the Earth is cooled in large measure by air currents (in various forms including
deep clouds) that carry heat upward and poleward. One consequence of this picture
is that it is the greenhouse gases well above the Earth's surface that are of
primary importance in determining the temperature of the Earth. That is especially
important for water vapor, whose density decreases by about a factor of 1,000
between the surface and ten kilometers above the surface. Another consequence
is that one cannot even calculate the temperature of the Earth without models
that accurately reproduce the motions of the atmosphere. Indeed, present models
have large errors here--on the order of 50 percent. Not surprisingly, those
models are unable to calculate correctly either the present average temperature
of the Earth or the temperature ranges from the equator to the poles. Rather,
the models are adjusted or "tuned'' to get those quantities approximately
It is still of interest to ask what we would expect a doubling of carbon dioxide
to do. A large number of calculations show that if this is all that happened,
we might expect a warming of from .5 to 1.2 degrees centigrade. The general
consensus is that such warming would present few, if any, problems. But even
that prediction is subject to some uncertainty because of the complicated way
the greenhouse effect operates. More important, the climate is a complex system
where it is impossible for all other internal factors to remain constant. In
present models those other factors amplify the effects of increasing carbon
dioxide and lead to predictions of warming in the neighborhood of four to five
degrees centigrade. Internal processes within the climate system that change
in response to warming in such a manner as to amplify the response are known
as positive feedbacks. Internal processes that diminish the response are known
as negative feedbacks. The most important positive feedback in current models
is due to water vapor. In all current models upper tropospheric (five to twelve
kilometers) water vapor--the major greenhouse gas--increases as surface temperatures
increase. Without that feedback, no current model would predict warming in excess
of 1.7 degrees centigrade--regardless of any other factors. Unfortunately, the
way current models handle factors such as clouds and water vapor is disturbingly
arbitrary. In many instances the underlying physics is simply not known. In
other instances there are identifiable errors. Even computational errors play
a major role. Indeed, there is compelling evidence for all the known feedback
factors to actually be negative. In that case, we would expect the warming response
to carbon dioxide doubling alone to be diminished.
It is commonly suggested that society should not depend on negative feedbacks
to spare us from a "greenhouse catastrophe.'' What is omitted from such
suggestions is that current models depend heavily on undemonstrated positive
feedback factors to predict high levels of warming. The effects of clouds have
been receiving the closest scrutiny. That is not unreasonable. Cloud cover in
models is poorly treated and inaccurately predicted. Yet clouds reflect about
seventy-five watts per square meter. Given that a doubling of carbon dioxide
would change the surface heat flux by only two watts per square meter, it is
evident that a small change in cloud cover can strongly affect the response
to carbon dioxide. The situation is complicated by the fact that clouds at high
altitudes can also supplement the greenhouse effect. Indeed, the effects of
clouds in reflecting light and in enhancing the greenhouse effect are roughly
in balance. Their actual effect on climate depends both on the response of clouds
to warming and on the possible imbalance of their cooling and heating effects.
Similarly, factors involving the contribution of snow cover to reflectivity
serve, in current models, to amplify warming due to increasing carbon dioxide.
What happens seems reasonable enough; warmer climates presumably are associated
with less snow cover and less reflectivity--which, in turn, amplify the warming.
Snow is associated with winter when incident sunlight is minimal, however. Moreover,
clouds shield the Earth's surface from the sun and minimize the response to
snow cover. Indeed, there is growing evidence that clouds accompany diminishing
snow cover to such an extent as to make that feedback factor negative. If, however,
one asks why current models predict that large warming will accompany increasing
carbon dioxide, the answer is mostly due to the effect of the water vapor feedback.
Current models all predict that warmer climates will be accompanied by increasing
humidity at all levels. As already noted, such behavior is an artifact of the
models since they have neither the physics nor the numerical accuracy to deal
with water vapor. Recent studies of the physics of how deep clouds moisturize
the atmosphere strongly suggest that this largest of the positive feedbacks
is not only negative, but very large.
Not only are there major reasons to believe that models are exaggerating the
response to increasing carbon dioxide, but, perhaps even more significantly,
the models' predictions for the past century incorrectly describe the pattern
of warming and greatly overestimate its magnitude. The global average temperature
record for the past century or so is irregular and not without problems. It
does, however, show an average increase in temperature of about .45 degree centigrade
plus or minus .15 degree centigrade with most of the increase occurring before
1940, followed by some cooling through the early 1970s and a rapid (but modest)
temperature increase in the late 1970s. As noted, we have already seen an increase
in "equivalent'' carbon dioxide of 50 percent. Thus, on the basis of models
that predict a four degree centigrade warming for a doubling of carbon dioxide
we might expect to have seen a warming of two degrees centigrade already. If,
however, we include the delay imposed by the oceans' heat capacity, we might
expect a warming of about one degree centigrade--which is still twice what has
been observed. Moreover, most of that warming occurred before the bulk of the
minor greenhouse gases were added to the atmosphere. Figure 2 shows what might
have been expected for models with differing sensitivities to a doubling of
carbon dioxide. What we see is that the past record is most consistent with
an equilibrium response to a doubling of about 1.3 degrees centigrade--assuming
that all the observed warming was due to increasing carbon dioxide. There is
nothing in the record that can be distinguished from the natural variability
of the climate, however.
If one considers the tropics, that conclusion is even more disturbing. There
is ample evidence that the average equatorial sea surface has remained within
plus or minus one degree centigrade of its present temperature for billions
of years, yet current models predict average warming of from two to four degrees
centigrade even at the equator. It should be noted that for much of the Earth's
history, the atmosphere had much more carbon dioxide than is currently anticipated
for centuries to come. I could, in fact, go on at great length listing the evidence
for small responses to a doubling of carbon dioxide; there are space constraints,
Consensus and the Current "Popular Vision''
Many studies from the nineteenth century on suggested that industrial and
other contributions to increasing carbon dioxide might lead to global warming.
Problems with such predictions were also long noted, and the general failure
of such predictions to explain the observed record caused the field of climatology
as a whole to regard the suggested mechanisms as suspect. Indeed, the global
cooling trend of the 1950s and 1960s led to a minor global cooling hysteria
in the 1970s. All that was more or less normal scientific debate, although the
cooling hysteria had certain striking analogues to the present warming hysteria
including books such as The Genesis Strategy by Stephen Schneider and Climate
Change and World Affairs by Crispin Tickell--both authors are prominent in support
of the present concerns as well--"explaining'' the problem and promoting
international regulation. There was also a book by the prominent science writer
Lowell Ponte (The Cooling) that derided the skeptics and noted the importance
of acting in the absence of firm, scientific foundation. There was even a report
by the National Research Council of the U.S. National Academy of Sciences reaching
its usual ambiguous conclusions. But the scientific community never took the
issue to heart, governments ignored it, and with rising global temperatures
in the late 1970s the issue more or less died. In the meantime, model calculations--especially
at the Geophysical Fluid Dynamics Laboratory at Princeton--continued to predict
substantial warming due to increasing carbon dioxide. Those predictions were
considered interesting, but largely academic, exercises--even by the scientists
The present hysteria formally began in the summer of 1988, although preparations
had been put in place at least three years earlier. That was an especially warm
summer in some regions, particularly in the United States. The abrupt increase
in temperature in the late 1970s was too abrupt to be associated with the smooth
increase in carbon dioxide. Nevertheless, James Hansen, director of the Goddard
Institute for Space Studies, in testimony before Sen. Al Gore's Committee on
Science, Technology and Space, said, in effect, that he was 99 percent certain
that temperature had increased and that there was some greenhouse warming. He
made no statement concerning the relation between the two.
Despite the fact that those remarks were virtually meaningless, they led the
environmental advocacy movement to adopt the issue immediately. The growth of
environmental advocacy since the 1970s has been phenomenal. In Europe the movement
centered on the formation of Green parties; in the United States the movement
centered on the development of large public interest advocacy groups. Those
lobbying groups have budgets of several hundred million dollars and employ about
50,000 people; their support is highly valued by many political figures. As
with any large groups, self-perpetuation becomes a crucial concern. "Global
warming'' has become one of the major battle cries in their fundraising efforts.
At the same time, the media unquestioningly accept the pronouncements of those
groups as objective truth.
Within the large-scale climate modelling community--a small subset of the
community interested in climate--however, the immediate response was to criticize
Hansen for publicly promoting highly uncertain model results as relevant to
public policy. Hansen's motivation was not totally obvious, but despite the
criticism of Hansen, the modelling community quickly agreed that large warming
was not impossible. That was still enough for both the politicians and advocates
who have generally held that any hint of environmental danger is a sufficient
basis for regulation unless the hint can be rigorously disproved. That is a
particularly pernicious asymmetry, given that rigor is generally impossible
in environmental sciences.
Other scientists quickly agreed that with increasing carbon dioxide some warming
might be expected and that with large enough concentrations of carbon dioxide
the warming might be significant. Nevertheless, there was widespread skepticism.
By early 1989, however, the popular media in Europe and the United States were
declaring that "all scientists'' agreed that warming was real and catastrophic
in its potential.
As most scientists concerned with climate, I was eager to stay out of what
seemed like a public circus. But in the summer of 1988 Lester Lave, a professor
of economics at Carnegie Mellon University, wrote to me about being dismissed
from a Senate hearing for suggesting that the issue of global warming was scientifically
controversial. I assured him that the issue was not only controversial but also
unlikely. In the winter of 1989 Reginald Newell, a professor of meteorology
at the Massachusetts Institute of Technology, lost National Science Foundation
funding for data analyses that were failing to show net warming over the past
century. Reviewers suggested that his results were dangerous to humanity. In
the spring of 1989 I was an invited participant at a global warming symposium
at Tufts University. I was the only scientist among a panel of environmentalists.
There were strident calls for immediate action and ample expressions of impatience
with science. Claudine Schneider, then a congressman from Rhode Island, acknowledged
that "scientists may disagree, but we can hear Mother Earth, and she is
crying.'' It seemed clear to me that a very dangerous situation was arising,
and the danger was not of "global warming'' itself.
In the spring of 1989 I prepared a critique of global warming, which I submitted
to Science, a magazine of the American Association for the Advancement of Science.
The paper was rejected without review as being of no interest to the readership.
I then submitted the paper to the Bulletin of the American Meteorological Society,
where it was accepted after review, rereviewed, and reaccepted--an unusual procedure
to say the least. In the meantime, the paper was attacked in Science before
it had even been published. The paper circulated for about six months as samizdat.
It was delivered at a Humboldt conference at M.I.T. and reprinted in the Frankfurter
In the meantime, the global warming circus was in full swing. Meetings were
going on nonstop. One of the more striking of those meetings was hosted in the
summer of 1989 by Robert Redford at his ranch in Sundance, Utah. Redford proclaimed
that it was time to stop research and begin acting. I suppose that that was
a reasonable suggestion for an actor to make, but it is also indicative of the
overall attitude toward science. Barbara Streisand personally undertook to support
the research of Michael Oppenheimer at the Environmental Defense Fund, although
he is primarily an advocate and not a climatologist. Meryl Streep made an appeal
on public television to stop warming. A bill was even prepared to guarantee
Americans a stable climate.
By the fall of 1989 some media were becoming aware that there was controversy
(Forbes and Reader's Digest were notable in that regard). Cries followed from
environmentalists that skeptics were receiving excessive exposure. The publication
of my paper was followed by a determined effort on the part of the editor of
the Bulletin of the American Meteorological Society, Richard Hallgren, to solicit
rebuttals. Such articles were prepared by Stephen Schneider and Will Kellogg,
a minor scientific administrator for the past thirty years, and those articles
were followed by an active correspondence mostly supportive of the skeptical
spectrum of views. Indeed, a recent Gallup poll of climate scientists in the
American Meteorological Society and in the American Geophysical Union shows
that a vast majority doubts that there has been any identifiable man-caused
warming to date (49 percent asserted no, 33 percent did not know, 18 percent
thought some has occurred; however, among those actively involved in research
and publishing frequently in peer-reviewed research journals, none believes
that any man-caused global warming has been identified so far). On the whole,
the debate within the meteorological community has been relatively healthy and,
in this regard, unusual.
Outside the world of meteorology, Greenpeace's Jeremy Legett, a geologist
by training, published a book attacking critics of warming---especially me.
George Mitchell, Senate majority leader and father of a prominent environmental
activist, also published a book urging acceptance of the warming problem (World
on Fire: Saving an Endangered Earth). Sen. Gore recently published a book (Earth
in the Balance: Ecology and the Human Spirit). Those are just a few examples
of the rapidly growing publications on warming. Rarely has such meager science
provoked such an outpouring of popularization by individuals who do not understand
the subject in the first place.
The activities of the Union of Concerned Scientists deserve special mention.
That widely supported organization was originally devoted to nuclear disarmament.
As the cold war began to end, the group began to actively oppose nuclear power
generation. Their position was unpopular with many physicists. Over the past
few years, the organization has turned to the battle against global warming
in a particularly hysterical manner. In 1989 the group began to circulate a
petition urging recognition of global warming as potentially the great danger
to mankind. Most recipients who did not sign were solicited at least twice more.
The petition was eventually signed by 700 scientists including a great many
members of the National Academy of Sciences and Nobel laureates. Only about
three or four of the signers, however, had any involvement in climatology. Interestingly,
the petition had two pages, and on the second page there was a call for renewed
consideration of nuclear power. When the petition was published in the New York
Times, however, the second page was omitted. In any event, that document helped
solidify the public perception that "all scientists'' agreed with the disaster
scenario. Such a disturbing abuse of scientific authority was not unnoticed.
At the 1990 annual meeting of the National Academy of Sciences, Frank Press,
the academy's president, warned the membership against lending their credibility
to issues about which they had no special knowledge. Special reference was made
to the published petition. In my opinion what the petition did show was that
the need to fight "global warming'' has become part of the dogma of the
liberal conscience--a dogma to which scientists are not immune.
At the same time, political pressures on dissidents from the "popular
vision'' increased. Sen. Gore publicly admonished "skeptics'' in a lengthy
New York Times op-ed piece. In a perverse example of double-speak he associated
the "true believers'' in warming with Galileo. He also referred, in another
article, to the summer of 1988 as the Kristallnacht before the warming holocaust.
The notion of "scientific unanimity'' is currently intimately tied to
the Working Group I report of the Intergovernmental Panel on Climate Change
issued in September 1990. That panel consists largely of scientists posted to
it by government agencies. The panel has three working groups. Working Group
I nominally deals with climate science. Approximately 150 scientists contributed
to the report, but university representation from the United States was relatively
small and is likely to remain so, since the funds and time needed for participation
are not available to most university scientists. Many governments have agreed
to use that report as the authoritative basis for climate policy. The report,
as such, has both positive and negative features. Methodologically, the report
is deeply committed to reliance on large models, and within the report models
are largely verified by comparison with other models. Given that models are
known to agree more with each other than with nature (even after "tuning''),
that approach does not seem promising. In addition, a number of the participants
have testified to the pressures placed on them to emphasize results supportive
of the current scenario and to suppress other results. That pressure has frequently
been effective, and a survey of participants reveals substantial disagreement
with the final report. Nonetheless, the body of the report is extremely ambiguous,
and the caveats are numerous. The report is prefaced by a policymakers' summary
written by the editor, Sir John Houghton, director of the United Kingdom Meteorological
Office. His summary largely ignores the uncertainty in the report and attempts
to present the expectation of substantial warming as firmly based science. The
summary was published as a separate document, and, it is safe to say that policymakers
are unlikely to read anything further. On the basis of the summary, one frequently
hears that "hundreds of the world's greatest climate scientists from dozens
of countries all agreed that.|.|.|.'' It hardly matters what the agreement refers
to, since whoever refers to the summary insists that it agrees with the most
extreme scenarios (which, in all fairness, it does not). I should add that the
climatology community, until the past few years, was quite small and heavily
concentrated in the United States and Europe.
While the International Panel on Climate Change's reports were in preparation,
the National Research Council in the United States was commissioned to prepare
a synthesis of the current state of the global change situation. The panel chosen
was hardly promising. It had no members of the academy expert in climate. Indeed,
it had only one scientist directly involved in climate, Stephen Schneider, who
is an ardent environmental advocate. It also included three professional environmental
advocates, and it was headed by a former senator, Dan Evans. The panel did include
distinguished scientists and economists outside the area of climate, and, perhaps
because of this, the report issued by the panel was by and large fair. The report
concluded that the scientific basis for costly action was absent, although prudence
might indicate that actions that were cheap or worth doing anyway should be
considered. A subcommittee of the panel issued a report on adaptation that argued
that even with the more severe warming scenarios, the United States would have
little difficulty adapting. Not surprisingly, the environmentalists on the panel
not only strongly influenced the reports, but failing to completely have their
way, attempted to distance themselves from the reports by either resigning or
by issuing minority dissents. Equally unsurprising is the fact that the New
York Times typically carried reports on that panel on page 46. The findings
were never subsequently discussed in the popular media--except for claims that
the reports supported the catastrophic vision. Nevertheless, the reports of
that panel were indicative of the growing skepticism concerning the warming
Indeed, the growing skepticism is in many ways remarkable. One of the earliest
protagonists of global warming, Roger Revelle, the late professor of ocean sciences
at Scripps Institution of Oceanography who initiated the direct monitoring of
carbon dioxide during the International Geophysical Year (1958), coauthored
with S. Fred Singer and Chauncy Starr a paper recommending that action concerning
global warming be delayed insofar as current knowledge was totally inadequate.
Another active advocate of global warming, Michael McElroy, head of the Department
of Earth and Planetary Sciences at Harvard, has recently written a paper acknowledging
that existing models cannot be used to forecast climate.
One might think that such growing skepticism would have some influence on
public debate, but the insistence on "scientific unanimity'' continues
unabated. At times, that insistence takes some very strange forms. Over a year
ago, Robert White, former head of the U.S. Weather Bureau and currently president
of the National Academy of Engineering, wrote an article for Scientific American
that pointed out that the questionable scientific basis for global warming predictions
was totally inadequate to justify any costly actions. He did state that if one
were to insist on doing something, one should only do things that one would
do even if there were no warming threat. Immediately after that article appeared,
Tom Wicker, a New York Times columnist and a confidant of Sen. Gore, wrote a
piece in which he stated that White had called for immediate action on "global
warming.'' My own experiences have been similar. In an article in Audubon Stephen
Schneider states that I have "conceded that some warming now appears inevitable.''
Differences between expectations of unmeasurable changes of a few tenths of
a degree and warming of several degrees are conveniently ignored. Karen White
in a lengthy and laudatory article on James Hansen that appeared in the New
York Times Sunday Magazine reported that even I agreed that there would be warming,
having "reluctantly offered an estimate of 1.2 degrees.'' That was, of
Most recently, I testified at a Senate hearing conducted by Sen. Gore. There
was a rather arcane discussion of the water vapor in the upper troposphere.
Two years ago, I had pointed out that if the source of water vapor in that region
in the tropics was from deep clouds, then surface warming would be accompanied
by reduced upper level water vapor. Subsequent research has established that
there must be an additional source--widely believed to be ice crystals thrown
off by those deep clouds. I noted that that source too probably acts to produce
less moisture in a warmer atmosphere. Both processes cause the major feedback
process to become negative rather than positive. Sen. Gore asked whether I now
rejected my suggestion of two years ago as a major factor. I answered that I
did. Gore then called for the recording secretary to note that I had retracted
my objections to "global warming.'' In the ensuing argument, involving
mostly other participants in the hearing, Gore was told that he was confusing
matters. Shortly thereafter, however, Tom Wicker published an article in the
New York Times that claimed that I had retracted my opposition to warming and
that that warranted immediate action to curb the purported menace. I wrote a
letter to the Times indicating that my position had been severely misrepresented,
and, after a delay of over a month, my letter was published. Sen. Gore nonetheless
claims in his book that I have indeed retracted my scientific objections to
the catastrophic warming scenario and also warns others who doubt the scenario
that they are hurting humanity.
Why, one might wonder, is there such insistence on scientific unanimity on
the warming issue? After all, unanimity in science is virtually nonexistent
on far less complex matters. Unanimity on an issue as uncertain as "global
warming'' would be surprising and suspicious. Moreover, why are the opinions
of scientists sought regardless of their field of expertise? Biologists and
physicians are rarely asked to endorse some theory in high energy physics. Apparently,
when one comes to "global warming,'' any scientist's agreement will do.
The answer almost certainly lies in politics. For example, at the Earth Summit
in Rio, attempts were made to negotiate international carbon emission agreements.
The potential costs and implications of such agreements are likely to be profound
for both industrial and developing countries. Under the circumstances, it would
be very risky for politicians to undertake such agreements unless scientists
"insisted.'' Nevertheless, the situation is probably a good deal more complicated
than that example suggests.
The Temptation and Problems of "Global Warming''
As Aaron Wildavsky, professor of political science at Berkeley, has quipped,
"global warming'' is the mother of all environmental scares. Wildavsky's
view is worth quoting. "Warming (and warming alone), through its primary
antidote of withdrawing carbon from production and consumption, is capable of
realizing the environmentalist's dream of an egalitarian society based on rejection
of economic growth in favor of a smaller population's eating lower on the food
chain, consuming a lot less, and sharing a much lower level of resources much
more equally.'' In many ways Wildavsky's observation does not go far enough.
The point is that carbon dioxide is vitally central to industry, transportation,
modern life, and life in general. It has been joked that carbon dioxide controls
would permit us to inhale as much as we wish; only exhaling would be controlled.
The remarkable centrality of carbon dioxide means that dealing with the threat
of warming fits in with a great variety of preexisting agendas--some legitimate,
some less so: energy efficiency, reduced dependence on Middle Eastern oil, dissatisfaction
with industrial society (neopastoralism), international competition, governmental
desires for enhanced revenues (carbon taxes), and bureaucratic desires for enhanced
The very scale of the problem as popularly portrayed and the massive scale
of the suggested responses have their own appeal. The Working Group I report
of the Intergovernmental Panel on Climate Change suggested, for example, that
a 60 percent reduction in carbon dioxide emissions might be needed. Such a reduction
would call for measures that would be greater than those that have been devoted
to war and defense. And just as defense has dealt with saving one's nation,
curbing "global warming'' is identified with saving the whole planet! It
may not be fortuitous that this issue is being promoted at just the moment in
history when the cold war is ending.
Major agencies in the United States, hitherto closely involved with traditional
approaches to national security, have appropriated the issue of climate change
to support existing efforts. Notable among those agencies are NASA, the Department
of Defense, and the Department of Energy. The cold war helped spawn a large
body of policy experts and diplomats specializing in issues such as disarmament
and alliance negotiations. In addition, since the Yom Kippur War, energy has
become a major component of national security with the concomitant creation
of a large cadre of energy experts. Many of those individuals see in the global
change issue an area in which to continue applying their skills. Many scientists
also feel that national security concerns formed the foundation for the U.S.
government's generous support of science. As the urgency of national security,
traditionally defined, diminishes, there is a common feeling that a substitute
foundation must be established. "Saving the planet'' has the right sort
of sound to it. Fundraising has become central to environmental advocates' activities,
and the message underlying some of their fundraising seems to be "pay us
or you'll fry.''
Clearly, "global warming'' is a tempting issue for many very important
groups to exploit. Equally clearly, though far less frequently discussed, are
the profound dangers in exploiting that issue. As we shall also see, there are
good reasons why there has been so little discussion of the downside of responding
to "global warming.''
A parochial issue is the danger to the science of climatology. As far as I
can tell, there has actually been reduced funding for existing climate research.
That may seem paradoxical, but, at least in the United States, the vastly increased
number of scientists and others involving themselves in climate as well as the
gigantic programs attaching themselves to climate have substantially outstripped
the increases in funding. Perhaps more important are the pressures being brought
to bear on scientists to get the "right'' results. Such pressures are inevitable,
given how far out on a limb much of the scientific community has gone. The situation
is compounded by the fact that some of the strongest proponents of "global
warming'' in Congress are also among the major supporters of science (Sen. Gore
is notable among those). Finally, given the momentum that has been building
up among so many interest groups to fight "global warming,'' it becomes
downright embarrassing to support basic climate research. After all, one would
hate to admit that one had mobilized so many resources without the basic science's
being in place. Nevertheless, given the large increase in the number of people
associating themselves with climatology and the dependence of much of that community
on the perceived threat of warming, it seems unlikely that the scientific community
will offer much resistance. I should add that as ever greater numbers of individuals
attach themselves to the warming problem, the pressures against solving the
problem grow proportionally; an inordinate number of individuals and groups
depend on the problem's remaining.
In addition to climatologists, are there other groups that are at risk? Here,
one might expect that industry could be vulnerable, and, indeed, it may be.
At least in the United States, however, industries seem to be primarily concerned
with improving their public image, often by supporting environmental activists.
Moreover, some industries have become successful at profiting from environmental
regulation. The most obvious example is the waste management industry. Even
electric utility companies have been able to use environmental measures to increase
the base on which their regulated profits are calculated. It is worth noting
that about 1.7 trillion dollars have been spent on the environment over the
past decade. The environment, itself, qualifies as one of our major industries.
If Wildavsky's scenario is correct, the major losers would be ordinary people.
Wealth that could have been used to raise living standards in much of the world
would be squandered. Living standards in the developed world would decrease.
Regulatory apparatuses would restrict individual freedom on an unprecedented
scale. Here too, however, one cannot expect much resistance to proposed actions--at
least not initially. Public perceptions, under the influence of extensive, deceptive,
and one-sided publicity, can become disconnected from reality. For example,
Alabama has had a pronounced cooling trend since 1935. Nevertheless, a poll
among professionals in Alabama found that about 95 percent of the participants
believed that the climate had been warming over the past fifty years and that
the warming was due to the greenhouse effect. Public misperceptions coupled
with a sincere desire to "save the planet'' can force political action
even when politicians are aware of the reality.
What the above amounts to is a societal instability. At a particular point
in history, a relatively minor suggestion or event serves to mobilize massive
interests. While the proposed measures may be detrimental, resistance is largely
absent or coopted. In the case of climate change, the probability that the proposed
regulatory actions would for the most part have little impact on climate, regardless
of the scenario chosen, appears to be of no consequence.
Modelling and Societal Instability
So far I have emphasized the political elements in the current climate hysteria.
There can be no question, however, that scientists are abetting this situation.
Concerns about funding have already been mentioned. There is, however, another
perhaps more important element to the scientific support. The existence of modern
computing power has led to innumerable modelling efforts in many fields. Supercomputers
have allowed us to consider the behavior of systems seemingly too complex for
other approaches. One of those systems is climate. Not surprisingly, there are
many problems involved in modelling climate. For example, even supercomputers
are inadequate to allow long-term integrations of the relevant equations at
adequate spatial resolutions. At presently available resolutions, it is unlikely
that the computer solutions are close to the solutions of the underlying equations.
In addition, the physics of unresolved phenomena such as clouds and other turbulent
elements is not understood to the extent needed for incorporation into models.
In view of those problems, it is generally recognized that models are at present
experimental tools whose relation to the real world is questionable.
While there is nothing wrong in using those models in an experimental mode,
there is a real dilemma when they predict potentially dangerous situations.
Should scientists publicize such predictions since the models are almost certainly
wrong? Is it proper to not publicize the predictions if the predicted danger
is serious? How is the public to respond to such predictions? The difficulty
would be diminished if the public understood how poor the models actually are.
Unfortunately, there is a tendency to hold in awe anything that emerges from
a sufficiently large computer. There is also a reluctance on the part of many
modellers to admit to the experimental nature of their models lest public support
for their efforts diminish. Nevertheless, with poor and uncertain models in
wide use, predictions of ominous situations are virtually inevitable--regardless
Such weak predictions feed and contribute to what I have already described
as a societal instability that can cascade the most questionable suggestions
of danger into major political responses with massive economic and social consequences.
I have already discussed some of the reasons for this instability: the existence
of large cadres of professional planners looking for work, the existence of
advocacy groups looking for profitable causes, the existence of agendas in search
of saleable rationales, and the ability of many industries to profit from regulation,
coupled with an effective neutralization of opposition. It goes almost without
saying that the dangers and costs of those economic and social consequences
may be far greater than the original environmental danger. That becomes especially
true when the benefits of additional knowledge are rejected and when it is forgotten
that improved technology and increased societal wealth are what allow society
to deal with environmental threats most effectively. The control of societal
instability may very well be the real challenge facing us.
What does the lag of CO2 behind temperature in ice cores tell us about global
Filed under: Paleoclimate Greenhouse gases FAQ group @ 9:42 am - ()
This is an issue that is often misunderstood in the public sphere and media,
so it is worth spending some time to explain it and clarify it. At least three
careful ice core studies have shown that CO2 starts to rise about 800 years
(600-1000 years) after Antarctic temperature during glacial terminations. These
terminations are pronounced warming periods that mark the ends of the ice ages
that happen every 100,000 years or so.
Does this prove that CO2 doesn't cause global warming? The answer is no.
The reason has to do with the fact that the warmings take about 5000 years
to be complete. The lag is only 800 years. All that the lag shows is that CO2
did not cause the first 800 years of warming, out of the 5000 year trend. The
other 4200 years of warming could in fact have been caused by CO2, as far as
we can tell from this ice core data. The 4200 years of warming make up about
5/6 of the total warming. So CO2 could have caused the last 5/6 of the warming,
but could not have caused the first 1/6 of the warming. It comes as no surprise
that other factors besides CO2 affect climate. Changes in the amount of summer
sunshine, due to changes in the Earth's orbit around the sun that happen every
21,000 years, have long been known to affect the comings and goings of ice ages.
Atlantic ocean circulation slowdowns are thought to warm Antarctica, also.
From studying all the available data (not just ice cores), the probable sequence
of events at a termination goes something like this. Some (currently unknown)
process causes Antarctica and the surrounding ocean to warm. This process also
causes CO2 to start rising, about 800 years later. Then CO2 further warms the
whole planet, because of its heat-trapping properties. This leads to even further
CO2 release. So CO2 during ice ages should be thought of as a "feedback",
much like the feedback that results from putting a microphone too near to a
loudspeaker. In other words, CO2 does not initiate the warmings, but acts as
an amplifier once they are underway. From model estimates, CO2 (along with other
greenhouse gases CH4 and N2O) causes about half of the full glacial-to-interglacial
warming. So, in summary, the lag of CO2 behind temperature doesn't tell us much
about global warming. [But it may give us a very interesting clue about why
CO2 rises at the ends of ice ages. The 800-year lag is about the amount of time
required to flush out the deep ocean through natural ocean currents. So CO2
might be stored in the deep ocean during ice ages, and then get released when
the climate warms.]
To read more about CO2 and ice cores, see Caillon et al., 2003, Science magazine
Climate Change Conference
'Disaster for Mobility and Enterprise in 2005'
As social scientists gather in Exeter for a Dangerous Climate Change
conference between 01 and 03 February, the outcome appears to have been decided
in advance with parallel claims for a climate disaster by 2026, unless taxes
rise. Organised by the government, it seems likely that car drivers and capitalists
will bear the brunt of any new pay us more tax and we`ll control the climate
initiatives that arise.
Several key scientific research results seem to be ignored by those attending,
particularly a set of peer-reviewed papers that show conclusively how carbon
dioxide levels do not cause climate change, but are a result of it.* These papers
show that changes in temperature occur naturally, up and down, and only then
does the level of carbon dioxide change. Given these results it's surprising
that politicians should claim to be able to make an effect happen before its
cause, in a modern day interpretation of the King Cnut delusion. Their escape
route of a CO2 feedback loop is blocked off by geological records showing carbon
dioxide levels up to 18 times higher than today's, with no thermal runaway happening
as a result, and the recent CO2 'spike' acknowledged as having no root cause
ABD Environment Spokesman Ben Adams comments
"While much of Europe is freezing in 2005, the atmosphere isn't warming
and Antarctic ice is thickening. IPCC climate models are in disrepute. So all
that remains is for the man-made global warming industry to re-invent the models
as successful and use them to scare everyone into compliance, using the full
weight of the UN and EU governments. This scaremongering can't change the science
we quote, which is not the result of ABD research but the work of eminent climate
Last week experts on climate and the atmosphere including Richard Lindzen (Professor
of Atmospheric Science at Massachusetts Institute of Technology) and man-made
global warming adversary Dr David Bellamy (botanist, ecologist and Professor
at the University of Nottingham) met at the Royal Institution in London to discuss
climate change. Dr Fred Singer, former US department of transportation chief
scientist and now head of the science and environment policy project, had to
dig his way through several feet of snow to catch his flight from the USA to
the conference as many parts of North America are also in the grip of a remarkably
cold winter. The conference concluded that climate change is a natural phenomenon,
but this received relatively little media exposure. It also highlighted how
the general public is being allowed to mislead itself when it comes to climate
change, and how scare stories can be managed for political gain.
"There's no point to this gathering except to cultivate headlines and
sustain the myth of dangerous man-made global warming primarily as a
means to an end"
. . . . continues Adams.
"Namely, the redistribution of wealth from European motorists to other
more politically correct groups, and from America plus other industrialised
nations to developing countries. Perhaps the scary smokescreen is to try and
limit electoral liability for the taxes involved. Scientists Friis-Christensen
and Lassen pointed out ten years ago that there's no human signal in temperature
data on the atmosphere, only in unsubstantiated groundstation readings riddled
with systematic errors."
Conveniently, those involved in perpetuating the myth try to make debate as
one-sided as possible. Recently a Lead Author resigned from the IPCC ** in protest
at abuse of science and inherent bias, while representation opposing Kyoto has
been prevented from speaking against government chief scientist Sir David King's
view on a wider platform *** . With little doubt, the Exeter proceedings will
be one-sided, bad news for mobility and enterprise, and any UK taxes hiked as
a result will fail to change the sun's activity, tectonics, the Milankovitch
cycles **** or the cosmic ray flux.
Arctic Warming Update
January 15, 2005
Supplemented January 26, 2005
Notice of relocated data source June 3, 2005
Once again claims are flying thick and fast regarding dramatic, in fact, unprecedented
Arctic warming. Once again, we look at the available data, now updated to the
end of 2004. Once again, we find the claims to be dead flat wrong. Note: subsequent
to NASA's server upgrade the correct URL for zonal temperature anomalies is:
We begin, as is our want, with the bare annual mean temperature
track for the region 64N-90N. We use this particular dataset since the Arctic
Circle describes a line of latitude near but south of the north pole marking
the northernmost point at which the sun is visible on the northern winter solstice
and the southernmost point at which the midnight sun can be seen on the northern
summer solstice - roughly the parallel of latitude approximately 66°33'
north and we are thus confident of having captured the boundary between the
North Temperate and North Frigid zones. Rather obviously it indicates a sustained
warming, followed by a cooling and recovery.
Of course, some people want (and others need) rather more aggressive highlighting
of apparent trends and so we present the same data with shading and trend lines
added. This next graphic shows the very same data with split trends and shading
to highlight the warming trend 1880 through 1938 (the warmest year in the series).
Had the pre-1938 trend continued there would certainly be some Arctic warming
to talk about. Just as well we are not staunch advocates of post hoc, ergo propter
hoc or we'd be claiming that increasing the rate of atmospheric CO2 increment
stops Arctic warming.
We would be remiss if we did not point out the most significant warming in
And now, trends 1918-1938 and 1966-2003 compared (yes, we know data is available
in the series to include 2004 but the region's annual mean temperature fell
two-thirds of one degree C from the partial series maximum value of 2003). Finally,
let's look at the low-high trend values for the warming periods before and after
the cooling demonstrated 1938 - 1966.
In other words, we'll consider three decades of cooling an anomaly in the
series and take a longer perspective - how has the Arctic recovery from the
Little Ice Age varied over roughly one hundred and twenty years?
The answer is, it hasn't. The post-LIA recovery seems to be trundling along
the same as before, despite an Earth-insignificant setback of a few decades
in between. The last 3-4 decades are not the fastest warming period of the series
nor the slowest, rather, with the longer-term perspective they appear very ordinary.
So, according to data from the Global Historical Climatology Network (GHCN),
from this file hosted by NASA's Goddard Institute for Space Studies (GISS),
there has been no net Arctic warming since 1938, the Arctic did warm quite abruptly
over the two decades prior to that, has subsequently cooled and (nearly) recovered
to what it was before being so rudely interrupted. Beyond all doubt atmospheric
carbon dioxide content has increased over the period, mainly from about the
time the Arctic shifted to cooling mode for a spell. That trace gas increase
has had no apparent effect on the Arctic's post-LIA warming. Since the rate
of warming is unchanged and the net Arctic temperature has not increased in
almost 7 decades it is very difficult to see what all the hysteria is about.
Supplemental, January 26, 2005:
It's becoming fashionable to claim rapid Antarctic warming too - from NYT
yesterday: "Antarctica, Warming, Looks Ever More Vulnerable" - "A
continent is quickly changing. The questions are how and why." (New York
Times) Antarctica, however, is not warming. While the enhanced greenhouse hypothesis
insists the Antarctic should demonstrate the most dramatic response to rising
atmospheric carbon dioxide levels due to its cold, dry atmosphere, the simple
fact is the Antarctic is not cooperating.
South Polar air samples record atmospheric CO2 rising from 328 ppmv to 373
ppmv subsequent to the 1949-1974 temperature increase - almost 15% increase
apparently without affecting Polar temperatures, while startling temperature
changes of ~4 °C (+ve and -ve) are recorded in periods when we know atmospheric
CO2 was increasing at a more leisurely rate. A treasured hypothesis insists
increasing atmospheric CO2 should lead to increasing temperature and the South
Polar super-cold, super-dry air mass should respond dramatically. Well, we looked
for the CO2 increment and it is obvious. We looked for the temperature increment
and... what? Found it missing? There it was, gone? We've already had the "you
could see the warming if it wasn't being hidden by the cooling (which is being
hidden by the warming)" thing - see "Stratospheric Cooling?"
What is Big Warming going to come up with now - "Please Miss, the ozone
hole ate my Antarctic warming"?
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