Climate change reared its head again last week at the Asia-Pacific
Economic Cooperation summit in Sydney, where participating heads of
state struggled to reach a consensus on how to reduce emissions of
carbon dioxide (CO2). The political squabbling, global warming true
believers will say, stands in stark contrast to the scientific consensus
that the greenhouse effect, a product of increasing CO2 in the
atmosphere, is causing dramatic climate change. There’s just one problem
with this view: There’s a lot less to that "scientific consensus" than
meets the eye.
When millennial climate change patterns are mentioned, many people point
to the "2,500 scientists from 130 countries" who have agreed that global
warming is caused by the greenhouse effect. Yet not even the
International Panel of Climate Change to which these people refer
presents definitive scientific proof that the present warming is mostly
caused by the greenhouse effect. It is simply an assumption that has
morphed into a fact.
Since the physics behind CO2’s greenhouse effect has long been well
known, the IPCC made the assumption that post-1900 warming was caused by
it. They assembled a large number of scientists, mostly meteorologists
and physicists (but, interestingly, not many climatologists), and tried
to prove their hypothesis using supercomputer models. They have
continued to work in this way despite important new evidence from
ice-core data showing that temperature rises tend to precede CO2
increases by about 1,000 years. With all of the media attention that
this assumption now enjoys, natural temperature changes have been mostly
forgotten. Yet in reality they persist; they’re simply not being
studied. This is the single greatest failing of the IPCC.
Meanwhile, a tree-ring study that was conducted to estimate historical
temperatures was published in 1999. It showed that over the years,
global temperatures had decreased gradually between the years 1000 and
1900, at which time they suddenly began to increase. Its graph was
nicknamed "the hockey stick" because of its shape and it has been
prominently displayed in the summary of the IPCC’s 2001 report.
After glancing at this figure, many policy makers, environmental
advocacy groups and scientists around the world were convinced that the
greenhouse effect began after 1900. But the hockey-stick graph was later
discredited. Two Canadian statisticians found that the authors of the
graph made a statistical error in dealing with the tree-ring data. After
correcting the error, the two researchers could not reproduce the sharp
upturn of the curve — even though they were using the very same data.
In understanding the present warming trend, it is absolutely essential
to learn more about climate change in the distant past — or at least
during the last 1,000 years. But many scientists, particularly younger
ones, prefer to work only with data collected after 1975, when satellite
data became available. With only 30 years worth of data, their results
are little more than climatological snapshots of what is really a slow,
long-term process. The latest accurate satellite images of sea ice
distribution in the
computer screen; but it is impossible to obtain such quality data for
periods before 1975.
It is for this reason that only a minority of scientists are studying
natural climate change, including multi-decadal oscillations and
centurial climate change, which is the true realm of climatology. These
areas have not been priorities for the IPCC.
They should be. During winter,
solid. This occurred on and off between 1400 and 1800 during a period
called the "Little Ice Age" when temperatures dropped by as much as 1.5
degrees Celsius, which came after the medieval warm period around 1000.
The anomaly of the Little Ice Age corrected itself, of course, through
something called rebounding. The rebounding rate is estimated at 0.5
degrees Celsius per century. Since our present warming rate is roughly
0.6 degrees Celsius per century, the greenhouse effect caused by CO2 may
represent only a 0.1 degree Celsius increase in temperature over the
course of a century.
There is no doubt that global warming is in progress. But much of it can
be attributed to the rebounding effect from the Little Ice Age.
Recovering from a cool period is, of course, warming — but it is
nothing to panic about. Ice core data from the
many periodic warming and cooling periods during the last 10,000 years.
The present warming phase is far from the warmest.
Scientists have no clear knowledge of the cause of the Little Ice Age
and of the subsequent rebound; or of the Big Ice Age; or of a warm
period when the
period. In fact, IPCC scientists do not understand the causes of the
rapid increase of temperature from 1910 to 1945; or the decrease from
1945 to 1975, when CO2 levels were rising. Without understanding these
recent changes, it is premature for the IPCC to jump to the conclusion
that CO2 is the main cause of the last 30 years of global warming.
Many people claim scientists proved the greenhouse effect with models
run on supercomputers. But a supercomputer is not a crystal ball.
Scientists merely enter observed (or expected) CO2 amounts into a
computer and, using an algorithm, a projection emerges. No computer can
accurately represent such a gigantic system as the Earth with all its
unknown processes, such as the causes of the medieval warm period and
the Little Ice Age. Therefore, no supercomputer, no matter how powerful,
is able to prove definitively a simplistic hypothesis that says the
greenhouse effect is responsible for warming.
Most people, including scientists who specialize in climatology, are not
aware of this weakness. In fact, the whole science of climate change
based on supercomputers and algorithmic models is still in its infancy.
A supercomputer cannot provide an approximate estimate of the
temperature in 2050 or 2100 because scientists are not able to instruct
it with all the the unknown processes that may be at play. Any
conclusions drawn from such results — which may be seen as nothing more
than an academic exercise — cannot and should not serve as hard facts
on which to base major international policies.
the factories of the developed world. This arrangement provides economic
benefits but also makes it impractical for Asian nations to reduce their
CO2 output. In fact, many political leaders in
hypocritical for the Western world to make such a demand. A truly
environmentally friendly policy would invest in innovation — in order
to increase energy efficiency — and not try to stifle whole economies
by attempting to do away with CO2 based on faulty science and wild
assumptions. It would be better for Asian countries such as
In the meantime, the integrity of climatology as a respectable science
has to be rehabilitated by bringing it back from its present confused
state and separating it entirely from politics. Only then can real
progress be made in predicting future climate patterns. At the same
time, environmental advocacy groups should return to their original goal
of protecting the environment from those things over which humanity
truly does have control.
/*Mr. Akasofu is the former director of the
an article appearing in the Sept. 2007 issue of the Far Eastern Economic