Friday » February 9 » 2007
The limits of
predictability
The Deniers -- Part VIII
Financial Post
Friday, February 02, 2007
January 19, 2007
When Frans Nieuwstadt, a distinguished Dutch meteorologist, engineer, editor
and professor, died in 2005, his obituary recounted seminal events in his
accomplished life. Among the experiences worthy of mention: Nieuwstadt had
studied under the celebrated professor, Henk Tennekes, and along with other
colleagues had been instrumental in convincing Tennekes to return to Europe in
1978 to become director of research at the Royal Netherlands Meteorological
Institute and later chairman of the august Scientific Advisory Committee of the
European Centre for Medium-Range Weather Forecasts.
Henk Tennekes, in ways both personal and professional, has touched an
extraordinary number of lives in his own distinguished career, among academics
and laymen alike. He is loved for his popular 1997 book, The Simple Science of
Flight From Insects to Jumbo Jets, and for his scholarly 1972 work, A First
Course in Turbulence, a classic that logs more than 2,000 citations on Google
Scholar. His provocative 1986 speech, "No Forecast Is Complete Without A Forecast
of Forecast Skill," led to the now-common discipline of "ensemble
forecasting" and spurred "multi-model forecasting." Scientists
today continue to wrestle with the fundamental critiques that he first
presented.
Tennekes became more than an inspiration for his students and a model for other
scientists, however. He also became an object lesson in the limits of
scientific inquiry. Because his critiques of climate science ran afoul of the
orthodoxy required by the Royal Netherlands Meteorological Institute, he was
forced to leave. Lesser scientists, seeing that even a man of Tennekes's
reputation was not free to voice dissent, learned their lesson. Ever since,
most scientists who harbour doubts about climate science bite their tongues and
keep their heads down.
Tennekes, more than any other individual, challenged the models that climate
scientists were constructing, saying models could never replicate the
complexity of the real world. What was needed was a different approach to
science, one that recognized inherent limits in such scientific tools and aimed
less to regulate the environment.
In a landmark speech to the American Meteorological Society in 1986, he argued
that meteorology was poised to be the first of the post- Newtonian sciences
because it was "at odds with the mainstream of the scientific enterprise
of the last 300 years. One goal of science is to control nature, but we know we
cannot control the weather. The goal of science is prediction, but we stand in
front of the limits of predictability."
Meteorology, in other words, would be the first scientific discipline to hit
this brick wall. As Tennekes argued, modern theory "unequivocally predicts
that no amount of improvement in the quality of the observation network or in
the power of computers will improve the average useful forecast range by more
than a few days."
Since Tennekes' speech, a host of scientists have sought to extend the bounds
of modelling. They have seen success, but only on the scale Tennekes predicted.
In a paper presented in 2003, a team of European scientists detailed advances
in modelling science. "Since the day, almost 20 years ago, in which Henk
Tennekes stated … that 'no forecast is complete without a forecast of the
forecast skill,' the demand for numerical forecasting tools ... has been ever
increasing," they said, explaining efforts to make modelling reliable
beyond a three- to four-day period. Thanks to the intense efforts of a new
generation of climate modellers, modelling capability has advanced in some instances
by 12 to 36 hours, in others by several days. To extend the bounds further, the
paper announced a major new research initiative, designed to bring the
forecasting discipline to the 120-hour range.
Climate modelling is the basis of forecasts of climate change. Yet this
modelling, Tennekes believes, has little utility, and "there is no chance
at all that the physical sciences can produce a universally accepted scientific
basis for policy measures concerning climate change." Moreover, he states:
"There exists no sound theoretical framework for climate predictability
studies."
Not surprisingly, Tennekes abhors the dogma that he feels characterizes the
climate-change establishment, and the untoward role of climate science in
public-policy making. "We only understand 10% of the climate issue. That
is not enough to wreck the world economy with Kyoto-like measures."