Title: What Greenhouse Effect?
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Permanent Link: http://ufdc.ufl.edu/WL00000959/00001
 Material Information
Title: What Greenhouse Effect?
Physical Description: Book
Language: English
Publisher: St. Petersburg Times
 Subjects
Spatial Coverage: North America -- United States of America -- Florida
 Notes
Abstract: St. Petersburg Times Article December 29, 1988
General Note: Box 7, Folder 4 ( Vail Conference 1989 - 1989 ), Item 58
Funding: Digitized by the Legal Technology Institute in the Levin College of Law at the University of Florida.
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Bibliographic ID: WL00000959
Volume ID: VID00001
Source Institution: Levin College of Law, University of Florida
Holding Location: Levin College of Law, University of Florida
Rights Management: All rights reserved by the source institution and holding location.

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* Andrew R. Solow

What greenhouse effect?


Good science is often boring.
Good science fiction is usually ex-
citing. This may explain why re-
cent stories about the greenhouse
effect have been so exciting.
The typical story usually
told by a scientist in congressional
testimony goes something like
this: Global temperature depends
on atmospheric composition,
which is affected by human activi-
ties like burning fossil fuels. Con-
sequently, these activities may
cause atmospheric warming. This,
in a nutshell, is the greenhouse
effect.
The scientist mumbles some-
thing about being uncertain of the
actual timing, effects and magni-
tude of the greenhouse effect.
Then the fun begins. Disclaimers
aside, the scientist goes on to de-
scribe a future of stifling heat
waves, unrelenting drought and
rising seas.
The testimony is featured in
the next day's papers. The scien-
tist appears on the morning news
programs. Magazines print alarm-
ing stories. Calls for drastic action
ring out.
Meanwhile, those of us who are
also concerned about climate
change but who recognize the
enormous uncertainties and are
doing the difficult and (I like to
think) important work of reducing
these uncertainties, wistfully con-
template early retirement.
What can we really say about
future climate? There are three
ways of making climate predic-
tions. The first is through theory.
Theory says that increasing


the atmospheric concentration of
carbon dioxide may lead to
warming. Because the concentra-
tion of carbon dioxide is increasing,
we worry about warming. Beyond
that, we do not know enough about
climate processes to make useful
predictions from theory alone.
The second way of making cli-
mate predictions is through com-
puter models. These models are
large systems of equations repre-
senting our understanding of cli-
mate processes. Because our un-
derstanding is limited, the models
are of limited use. For example,
these models have a hard time
reproducing current climate from
current data. They cannot be ex-
pected to predict future climate
with any precision.
The third way of making cli-
mate predictions is by using exist-
ing data. Although this is the crud-
est way the past being a poten-
tially poor guide to the future -
existing data can, for example, tell
us if the greenhouse effect has
already begun. Temperature data
for the last 120 years show an
irregular warming of about 1 de-
gree Fahrenheit over the past cen-
tury. Over some periods, this
warming was relatively rapid. The
1980s has been such a period, as
were the 1890s and 1920s.
Because the greenhouse effect
is associated with warming, and
the data shows warming, can we
conclude that the greenhouse ef-
fect has begun? Not unless we are
prepared to believe that the only
cause of warming is the green-
house effect. There are indications


that the current warming is unre-
lated to the greenhouse effect.
The rate of warming is far below
that predicted under the green-
house effect.
The current warming started
before the greenhouse effect could
have begun. If the greenhouse ef-
fect had begun during the course of
the data, then we would see the
warming accelerate. No accelera-
tion appears in the data. The cur-
rent warming is consistent with a
mild post-glacial period, probably
the aftermath of the so-called "lit-
tle ice age" that ended during the
19th century.
The conclusion is that we can-
not yet make useful predictions
about climate, and that existing
data show no evidence of the
greenhouse effect. Many people
will be surprised to hear that this is
more or less the view expressed in
scientific journals, where articles
are subject to peer review. Unsub-
stantiated or misleading state-
ments only appear in such journals
when the review process fails.
Congressional testimony and inter-
views in the press are not subject
to peer review, and that is how
unsubstantiated and misleading
statements come to dominate pub-
lic discussion.
Some will say that the scientific
establishment demands an unrea-
sonable degree of certainty before
accepting a new idea. But in the
case of climate change, and partic-
ularly with regard to detecting
change with existing data, it is not
a question of the evidence being
tenuous. It is a question of there
being no evidence at all.
Andrew R. Solow is a statistician at
Woods Hole Oceanographic Institution
in Massachusetts.-


ST, Prg T~gg /' r______




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