From: SFPhysics@aol.com
Date: Wed Sep 27 2000 - 10:15:34 PDT
From: SFPhysics@aol.com Message-ID: <a8.b084e64.27038536@aol.com> Date: Wed, 27 Sep 2000 13:15:34 EDT Subject: RE: Global Warming = Where Goes Earth?
Dear Pinhole Listers:
While I was offended by political tone of the Global Warming and NPR, PBS
posting of WinterSun, the topic of saving the planet from a scientific point
of view should be part of classes such as "Integrated Science." As a science
teacher I try to teach open-mined inquiry and data gathering for a
step-by-step scientific approach. We should be encouraging our students to
get to the truth with verifiable facts and then postulate solutions. Taking
the political slant out of the discussion, let us look at some ideas about
global warming and our sources of energy that impact the planet:
1) We have no idea why the greatest global warming trend started some
12,000+ years ago. Certainly it was not the "oil companies" or we humans
that caused it.
2) We have had a serious increase in planetary temperatures in the last 100
years. Will this continue? So far the global warming predictions are just
extrapolations outside of our data points. We could just as well have a
return to the ice age with more sporadic interglacial periods like this one.
When the fossil fuels run out in about 100-200 years and we have not replaced
them with any new "concentrated" energy sources, where will an overpopulated
planet find energy? Will there be another ice age as CO2 levels fall then?
We don't have all of the complex facts involving the earth's planetary orbit,
the sun's variable output, the ocean's thermal responses, etc., to make a
cohesive workable model of the overall set of climatic systems. Let us
remember that for most of the planet's existence we did not have polar caps!
It was only when the ice ages started some 30 million years ago that the caps
first appeared. And, all it took was Mt. Panatubo (sp?) to drop the
planetary temperature averages for a couple of years.
3) We use petroleum and fossil fuels because they have the energy
concentrated in them. To get a fractional amount of the fossil fuel energy
from solar power we would have to cover much of the deserts in the
southwestern US with solar power farms. This would severely damage many of
the ecosystems there. One of the jobs of the mirror cleaners at the Barstow
solar power plant is to gather the bird carcasses up. To go for wind power
would mean that we would have to cover the tops of mountain ranges with
turbines. Hundreds of thousands of them. The number of birds that get
killed flying into the blades would not be even a significant part of the
damage that tearing up the land to plant the solid foundations these devices
need and running power lines all over the country side would bring.
4) Fission produces by products that we as a civilization find unacceptable
because who will be here guarding the toxic milieu for hundreds of thousands
of years. We could do what the old Soviet Union did and just post signs and
abandon vast tracks of land that have become unhabitable for the next 60,000+
years. Let us face it, fission reactors just have few positives against a
plethora of negatives.
5) Fusion seems no closer than it was some 30 years ago. The new "ignition
study facility" at the Lawrence Livermore Lab has been picketed by the
misguided who think that all the larger device is for is to build better
thermonuclear bombs. Unfortunately, Congress, in their infinite stupidity,
listen to such protests and scale back on funding of what should be a truly
great, almost clean, and virtually limitless energy source. There is much
doubt that fusion power will be any further along in the next 30 years with
funding cuts continuing. There may also be the possibility that fusion is
not technologically feasible far into the future.
6) Solar cells produce huge amounts of serious pollution in their
production. We could cover most of the buildings in the country with them
but this would only provide a small percentage of the power we use. The sun
shines at an approximate "useable" power of 1mW/cm2 on a good summer day at a
latitude of 29oNorth where San Francisco is. Your average home computer uses
300 Watts, the TV uses 100W, the electric clothes dryer 3600W, and so on. To
just run the TV you would need most of a roof of a residential home. This is
because the current best solar cells are still less than 40% efficient in
their energy conversion and they must do double duty in charging batteries
for nighttime energy use. Production of batteries is another serious source
of long-term dangerous pollutants, mostly heavy metals.
7) Hydroelectric plants on rivers and streams produce thermal pollution and
change ecosystems drastically. About all of the economically useable sites
for hydro have been built on. We cannot expand on this source of energy much
more.
8) Geothermal plants also pollute with sulfur compounds such as sulfur
dioxide that comes up with the steam. The steam also must be treated to
remove "geyser dust" witch eats turbine blades for lunch. Energy from
geothermal plants is neither cheap nor nonpolluting In tapping a steam field
new wells must constantly be found to replace the wells that are tapped out.
All of the tailings of the drilling become toxic waste that must be disposed
of or left on site for future clean up.
9) Orbiting solar cell arrays that beam power down to earth sound wonderful.
The only problems are that the atmosphere will warm appreciably in the
microwave beam path, airplanes could not fly through the beam without being
destroyed, birds would be cooked by the beam, putting it into orbit would
create millions of tons of pollution that would damage the ozone layer during
launches, etc. This was truly a pie-in-the-sky scheme.
All energy production is a dirty business and saving our planet from
ourselves is a much more complex task than just blaming the oil companies,
the forrest products industry, the military, or whatever target may be your
personal bugbear. We are living in an increasingly technological society
which requires energy and energy in increasing amounts. We already have the
possibility of roaming blackouts and service interruptions as we have heard
on the news this last summer. Quite literally we have reached the end of our
current energy production capacity. What can we do to minimize pollution and
enlarge energy production? Our students will inherit all of the problems.
Are they aware of them? Will we have given them the analytical tools to
address the problems?
Nothing should deter the science teacher and the scientist from posing the
key questions of what we can do to slow man's negative impact on the planet.
I ask my students, "How can we live here without causing irreversible damage?
Will we reach a point of planetary collapse where man drops back to a more
simple time after mass starvation, war, and pestilence? Will there be
another deeper "dark ages?"" All of the above are questions I have posed to
my students and the lively debates have gone on for weeks in my Lunch in the
Lab series.
Regards to all on the list and apologies for the long posting,
Al Sefl
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