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Last Stand in the classroom |
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Last Stand emphasizes
sustainability in recent presentations at Key West High School |
| The Leadership
in Environmental Conservation and Sustainability (LECS) program, made
possible by a grant from the Community Foundation of the Florida Keys (link
to CFFK's website),
got underway in April and May, with classroom presentations by four
Last
Stand volunteers. The volunteers, board members of
Last Stand,
gave presentations on conservation and alternative resources to
9th-grade science students of Key West High School teacher Joy Smith.
Topics included
water resources, solar power, wind power, and hydroponic gardening.
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| George Halloran spoke to the classes about water.
His
talk included a history of water consumption in the Keys, from the
pre-pipeline (pre-1941) days when all residents used cisterns and wells,
to the present, with all our water coming from FKAA well fields in
Florida City and with unprecedented demands for more
water. The Keys are limited to 17 million gallons per
day, and our peak consumption is at or near the limit,
with any increase in our allotment unlikely. Mr. Halloran
described the freshwater lenses that lie beneath Key
West and several other larger islands in the Keys.
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Named for their shape (like that of a lens) they are
shallow deposits of rainwater which collects in the
pervious subsurface rock and floats on top of saltwater.
While sizeable, Keys freshwater lenses, which depend on rainfall, aren't
extensive enough for a dependable water source, but could be useful in
emergencies, and for things such as watering gardens. While our
water supply from the mainland is the cleanest in South Florida despite
the pipe travel time, our water supply is susceptible to saltwater
intrusion into the Florida City wells. Rising sea-level and
excavation for development and rock quarries in South Miami-Dade
threaten our water supply in that way. Mr. Halloran had
the encouraging news that the Aqueduct Authority is once again
encouraging cisterns, that moves are afoot to exploit reuse of treated
wastewater for irrigation, and that composting toilets (using no water)
may get a nod of approval as enlightened minds have more influence.
He closed by expressing his hope that bright young minds such as those
at KWHS can turn things around once they get their hands on the
controls. |
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Mick Putney's presentation was on solar energy,
which is fitting since he and his wife live in a solar home they built
themselves on No Name Key... not connected to the power grid or water
pipeline.
The burning of fossil fuels to make electricity is a tremendous waste of
a precious commodity and has a terrible cost to the environment.
One answer to this destruction is solar power... most commonly, solar
panels using silicon to convert sunlight directly into electricity.
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A
solar system consists of four elements: solar panels to generate the
current, a charge controller to regulate it, a battery to store the
electricity for when the sun is not available, and an inverter to
transform the electricity to the type used in modern houses. A system
producing 2,500 watts will operate a typical household (except for air
conditioning) and costs $20,000 to $25,000.
Americans waste an incredible amount of energy. They use over twice as
much per capita as the residents of other advanced nations. Much of this
waste can be eliminated without much inconvenience, for example, by
using compact fluorescent light bulbs. Another large waste is in what
solar people call "ghost loads;" appliances which draw current 24/7 such
as cordless phones or televisions. Anything which has a remote, or a
small black box plugged into the outlet draws current continuously. The
amount in each case is small, but the cumulative demand constitutes a
significant portion of America's electrical consumption.
Since a solar house has a finite amount of power available, solar living
automatically teaches conservation. Residents in solar houses find that
conserving is generally painless, and can produce virtuous feelings.
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| Dennis Henize spoke to Ms. Smith's classes about wind as an energy source,
and being a meteorologist by profession, touched on a few global warming
issues. He highlighted what parts of the country are
feasible for large-scale generation of electricity by wind power.
That generally does not include the southeast U.S., unfortunately,
because wind is not strong or reliable enough. Wind power holds
much promise, though. Worldwide, and to a lesser extent nationwide
in the U.S., wind is supplying a greater percentage of electricity
needs.
Problems with wind energy are mainly with
distribution and storage. Optimum wind for generating electricity
is often far from where the power is needed... and generation depends on
the strength of the wind rather than on demand for electricity.
(With fossil-fuel-powered plants, output can be increased to meet
demand.) |
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| In some places, a
storage means is to pump water uphill by electricity
from wind generators, into reservoirs. In turn,
the water, which can be released when needed, turns
turbines to make electricity (hydro-electric).
Other relatively simple technologies, such as using
wind-made electricity to separate water into oxygen and
hydrogen (electrolysis) has promise both for storage
(hydrogen can be stored in tanks and burned as a
fuel) and distribution (it could be transported in
pipelines). Mr. Henize
briefly touched on global warming, explaining to the
students that among the numerous consequences of global
climate change, some are more likely than others... and
that some are wildly speculative. For example, it
is known that sea-level has risen approximately a foot
in the last 100 years, and that the rate of rise is
about twice as high now as at the beginning of the last
century. The rate at which it will continue to
rise, however, is highly speculative. He
also touched on the subject of "feedback mechanisms "
and how they can be either positive or negative... such
as the loss of polar ice. Ice and snow reflect
sunlight very effectively, and as ice disappears at the
poles and darker ground (or water) becomes exposed, more
sunlight is absorbed, more heating... a positive
feedback. Warmer oceans means more evaporation,
and in some places that means more clouds, which could
shade some places and actually decrease
warming... a negative feedback. Many such
reactions occur in nature, and a lot of the consequences
of global warming will be impossible to predict.
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| Mimi Stafford's
presentation was on hydroponic gardening. She
shared with the students her 30 years' experience
gardening in the Keys, using both organic soil gardening
and hydroponics. She related the history of
hydroponic gardening, the types of systems and methods
used, and the benefits of this intensive form of food
production.
The merits and satisfaction of growing some of one's own
food, as well as the peace of mind knowing that the food
is healthy and fresh and pesticide-free, were key points
of her presentation. She also stressed the environmental
merits of hydroponics as it uses far less water and
nutrients to produce the food, and does not contribute
to ground water contamination by nitrates and
phosphates. |
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The classroom presentations were recorded by Mr.
Ed Smith's media class, and will be edited for a DVD for the school
library and for distribution to other Monroe County schools.
The next phase of the LECS
program, involving a greenhouse project, will get underway next school
year. |