Editor's Note: In the last issue of The PEGG, we attempted to cut
off the debate on global warming, generated by articles written by Ken
Allen, P.Geoph. However, the two letters that follow had already been
composed before the last edition reached their writers.
About the time as the publication of the March PEGG, containing the article
by Ken Allen, P.Geoph, disputing the culprits in global warming (Sensible
Global Warming Policy is What We Need), researchers from London's Imperial
College outlined what they consider direct proof of enhanced greenhouse
effect. Comparing satellite data for 1970 and 1997, the colleagues were
able to demonstrate a reduction in infrared radiation escaping the Earth
(the wavelengths absorbed by various greenhouse gasses).
The controversy regarding Mr. Allen's remarks illustrates that the global
warming debate is not merely about science but also about the philosophical
biases that underlie our interpretations. Facts never speak for themselves;
rather, they are interpreted in light of existing, preconceived notions.
Inherent in our economic systems is a world view that puts man first.
The environment is treated as external -- a source of raw materials, a
sink for our wastes. This viewpoint has led to massive environmental degradation
and species extinction (rivaling the end of the Cretaceous period).
But from the ecological perspective, this ruling paradigm can be viewed
as dysfunctional with regards to the ecosphere. This perspective says
we are merely one species who co-evolved with the rest. Our existence
is predicated upon the existence and welfare of this community of species,
indeed the entire ecosphere.
Our technological prowess has not granted us immunity from ecological
destruction. The ecosphere is our life support system, we destroy and
alter it at our peril, without it we die. It is arrogant to believe we
can treat the Earth's atmosphere (which we poorly understand) as an open
sewer, without there being serious repercussions.
Our civilization is like the Exxon Valdez. We are drunk with the power
imparted by the hydrocarbon era. The vector of our society is towards
the rocks of ecological unsustainability, yet we maintain our course,
unwilling and (if we hesitate too long) perhaps ultimately unable to turn
this supertanker around.
The alarm has been sounded. Are we too drunk with our own power to hear?
J.Edward Mathison, P.Geol.
Long and the Short
There seems to be a fundamental split between environmentalists and earth
scientists-astronomers on global warming. The former place emphasize anthropomorphic
pollution, the latter natural events. Environmentalists tend to look at
short-term cause and effect, earth scientists the long-term.
Both camps have valid arguments. But as a geologist I favour the latter.
There is abundant evidence in the geological record of great changes in
the Earth's climate, but the most obvious in the context of global warming
is the latest Pleistocene ice age (Wisconsin). As little as 12,000 years
ago Canada was covered by a thick blanket of ice.
Whatever caused its retreat was certainly not influenced by man. Was it
changes in the sun's energy output or other natural events?
The earth has a long-tem "wobble" of about three degrees on
the orbital plane, due to precessional dynamics, with a 40,000-year cycle.
This will influence the angle of incidence of the sun's rays and (analogous
to our annual season) would create long-term cycles conducive to ice advances
and retreats. There are other astronomical cycles that occur over thousands
of years. Also due to orbital eccentricity, the sun moves closer to or
further from the earth in a 21,000-year cycle. There are many astronomic
events, long- and short-range, that affect the Earth's climate.
Many natural terrestrial events have important influence on climate. Volcanoes
pour millions of tons of emanations into the atmosphere. Natural forest
fires are a major pollutant. Oceanic currents and the melting of polar
ice play a role.
The interplay of so many variables, some poorly understood, make the predictive
value of climate models tenuous. And these are natural conditions -- nothing
to due with human activity. We have always existed in a narrow temperature
range ordained by nature: a delicate balance between dying from cold or
Man-made atmospheric pollution is a serious problem. What is debatable
is the relative amount of greenhouse gases produced by man versus those
form natural sources. Global warming is caused by the trapping of solar
heat by the build-up of carbon dioxide, water vapour, methane and other
components in the atmosphere.
Carbon dioxide is the favourite target and its increase is attributed
mainly to the burning of fossil fuels. But there are two ways to increase
CO2: increase the source ( the usual claim); or decrease the CO2-absorbing
elements (i.e. plants - the "carbon-sinks").
It is ironic that even as we are blaming fossil fuels, we are busily destroying
hundreds of square kilometres of virgin forest every day by logging, burning
and clearing of land. How much of atmospheric CO2 build-up is due to industrial
pollution and how much to the destruction of forests?
All plant life depends on absorbing CO2 from the atmosphere, while exuding
oxygen as a photosynthetic byproduct. All aerobic life on land depends
on the oxygen produced by plants. Additional CO2 in the atmosphere would
encourage more healthy plant growth. Forests are justifiably called the
"lungs of the earth." We would be in dire straits if the CO2
content dropped to the point of decimating forest growth!
Carbon dioxide, water and methane are culprits in the greenhouse effect.
Large quantities of methane are released from marshes, swamps and other
Population alone contributes to the global warming. It's increased sixfold,
from one billion in 1850 to six billion today. Every one of these people
exhales CO2 and water vapour with every breath. How many millions of tonnes
of CO2 and water vapour are added to atmospheric balance every day by
human respiration alone?
Would respiratory CO2 be classed as natural or manmade? The obvious solution
to respiratory pollution would not be popular with either camp!
Michael S. Stanton, P.Geol.,
I was very pleased that your lead story in the April 2001 issue of The
PEGG was about small site cogeneration - a subject that has been dear
to my heart for many years (Power to the Condos). I was anxious for details
of a practical application in Alberta.
I was a little less pleased to find what appear to be liberal use of journalistic
license and an inaccuracy. It is the sort of thing I would expect to see
in a pseudo science publication, but not in an official voice of APEGGA.
The story says: "CO2 emissions are less than half those associated
with a similar amount of power produced by a coal-fired plant." True,
but that's no surprise considering that the energy is being extracted
from natural gas (methane) with its four atoms of hydrogen for each one
of carbon, versus coal with nearly 100% carbon.
Moving on: "Using natural gas, NOx and total hydrocarbon emissions
amount to less than nine parts per million, and CO2 emissions are below
40 ppm." I expect the ending of that quotation should should have
read that CO (carbon monoxide) emissions are below 40 ppm.
The story also says that combustion is so close to perfect that you could
stay around and breathe the exhaust forever. Are we talking pure exhaust
here? I hardly think we could stay around and breath that forever, with
it's much reduced oxygen content and correspondingly increased carbon
If the CO is below 40 ppm, that's good, but it would have to be substantially
below. The Occupational Health and Safety limit for eight hours is 25
ppm for CO and 1,200 ppm for carbon dioxide.
If I am way off base here, I would be interested in knowing.
Norman Kennedy, P.Eng.