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Kevin T. Kilty
"What is going on here?" asks Forrest Mims
(Editorial,
TCS, 11 March 2005). Why do countless web sites all
appear to present unbalanced views of climate change?" Two
colleagues and I, all three of us amateurs at climate science,
constantly discuss ideas regarding climate change. Two of
these seem especially appropriate to Mims' timely proposal
for citizen scientists to make a balanced meal of this hash.
First, to answer Mims' question about what
is going on here, let me offer that this seems to be the natural
consequence of the sociology of science. Scientists in practice
do not behave like the mythically independent, skeptical analysts
they pretend to be. As one pertinent example, consider that
scientists tend to ride around on popular bandwagons. To ride
a bandwagon requires suspending one's skepticism about currently
fashionable ideas, and instead to be carried along by a scientific
herd. Henrion and Fischoff noticed this tendency in regard
to the measurement of fundamental physical constants, but
it appears over and over again in science. (1) In the current
context of climate change the bandwagon has become very large,
and with such a large group there are also large numbers of
gatekeepers involved. These gatekeepers are busy making sure
that official web sites and publications present a line of
information that is acceptable to those on the bandwagon.
Let me present an example.
Carbon Dioxide Sensitivity
Florens de Wit, a Dutch colleague, and I
have been examining the history of carbon dioxide (CO2) sensitivity
(2) estimates, and we have found that, while early estimates
varied quite widely, estimates made over the past two decades
have all converged on a range of values consistent with the
estimates of the Intergovernmental
Panel on Climate Change (IPCC). Is this because the members
of the IPCC are doing the best science and their estimated
range is most correct, or is it because the IPCC members are
seen as authorities, and everyone else is trimming their estimates
in order to be compatible with an esteemed group? I frankly
do not know. However, I have no reason to doubt some influence
of the bandwagon effect.
Borehole Temperatures
Seven years ago a cohort of earth scientists
were promoting the use of boreholes in soil to reconstruct
past climates. Most, if not all, of these efforts produced
past temperature records that were utterly consistent with
the Mann temperature record--the one that is now known widely
as the "hockey stick." There is no way such recovered soil
temperatures should conform so neatly to the hockey stick,
except by forcing the correspondence in an ad hoc
manner. The models used to convert soil temperatures to past
climate are unattainably idealistic. The physical situation
is fraught with confounding factors by the dozens, and the
process of diffusion destroys information needed to make past
climate estimates. In summary, such estimates ought to be
lousy at best and should be very noisy.
These scientists, wittingly or not, perhaps
became members of the bandwagon by trimming their results
to be compatible with those of a highly respected climate
scientist. As an ornery skeptic, I decided to write an article
exposing all of the problems with this methodology, and to
show by way of examples that widely differing climate histories
would produce indistinguishably similar borehole records.
I tried to obtain publication in the journal Geophysics
and then again in Nature . However, I could
never get my paper past the peer reviewers who act as gatekeepers
of science propriety. These reviewers prevented publication
of my paper not because they viewed it as a truthful threat,
but, because as riders on a bandwagon, they viewed it as completely
wrong and not worthy of publication space. In other words,
they are doing their job as they see it, even though it appears
detrimental to scientific discourse.
Recently, two borehole temperature scientists,
Louise Bodri and Vladimir Cermak, have shown that hydraulic
disturbance, just one effect I wish to illuminate, introduces
an uncertainty as large as the 20th century warming itself.(3)
As other confounders in this method become apparent and publicized,
more of the borehole temperature cohort will regain their
skepticism. Meanwhile the influence of the bandwagon riders
is to limit skepticism, limit scientific discourse and prevent
unpleasant facts from being publicized. The ornery, hard-core
skeptics, of course, will behave conversely. And so data presented
by each side will seem unnecessarily narrow in its view.
The idea of climate change diffusing into
the subsurface perhaps explains why the Arctic permafrost
is melting. The simple model is that global warming of the
air diffuses directly into the subsurface, but this is not
quite correct. Diffusion of temperature into the soil depends
on surface temperature and not on air temperature. Thus, air
temperature can remain constant, but surface temperature can
rise or fall and appear as disturbance of subsurface temperatures.
Thus, any factor that changes surface temperature, such as
radiative absorption, presents a potential for diffusion of
the attending surface temperature change to depth and for
melting permafrost. One observation concurrent with the melting
of permafrost is that the Arctic is also greening. Green plants
do a much better job of collecting solar radiation than does
icy, snowy tundra. Even if the new vegetation is apparent
at the surface for only a few weeks out of the year, it will
have a significant impact on subsurface temperatures. Perhaps
these green plants are making better use of growing season
and nutrients through the slightly increased CO2 level in
our atmosphere. If so, this is a "greenhouse effect,"
but an indirect one.
The Urban Heat Island
Effect
Finally, I'd like to share an interesting
calculation that shows the variety of avenues open to amateurs
in the investigation of climate change. Bob Perry, another
amateur colleague of mine, Florens deWit and I have done a
lot of thinking about the Urban Heat Island (UHI) effect.
Something we have pondered, but not explored very far, is
the direct effect of energy usage in climate change. This
appears to be an overlooked factor in confounding climatic
records in urban areas.
Take our current energy usage from all sources
(4 exajoules per year), divide by population, and then apply
the result to the population density in urban areas of North
America. The result is something like 1.5 Watts per square
meter. All of this energy eventually degrades to heat and
has to be either stored in the soil beneath the cities, radiated
away, or convected away. Our main point is that, by comparison,
the entire green house effect from CO2 and other greenhouse
gases plus all feedbacks is only about 2 watts per meter squared.
In other words our industrial thermal pollution in urban areas
nearly equals present estimates of the enhanced greenhouse
effect.
References and Notes
1. M. Henrion M. and B. Fischoff, Assessing
uncertainty in physical constants, American Journal of
Physics 54, 791-797 (1986).
2. CO2 sensitivity is the expected global
mean increase in temperature produced by an increase in atmospheric
CO2 concentration. We have tried to make all sensitivity estimates
comparable by converting them so they refer to a doubling
of CO2 concentration.
3. Louise Bodri and Valdimir
Cermak, Borehole temperatures, climate change and the pre-observational
surface air temperature mean: allowance for hydraulic conditions,
Global and Planetary Change 45, 265-276, (2005).
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