Trees are quiet, solar-powered air conditioners. On the next warm, sunny
day, walk from an open field or parking lot into a grove of trees. You will
easily discover what many more-elaborate scientific studies have revealed:
trees cool the environment.
Remember those very balmy days in March? The sun was at the same altitude
as it is in late September and the ground still held winter's cold. Yet
because the deciduous trees had not yet leafed out, it seemed very hot.
Trees cool the environment in at least four ways:
* They absorb solar energy and store it as molecular bonds in leaves and
* They transpire water which then evaporates. Anyone who has stood wet and
naked in the breeze knows that this has a cooling effect.
* They provide shade and create temperature differentials which encourage
* They consume carbon dioxide that would otherwise contribute to global
Trees provide other valuable services, too: they clean the air, build up
and protect the soil, and provide homes, foods and fuel for many of
nature's creatures, including ourselves.
Every spring, however, we are bombarded by advertisements for electric air
conditioners. These non-solar appliances use motors, compressors and fans
which consume many kilowatts of electricity and make lots of noise. They
also require chemical refrigerants, many of which destroy the ozone layer
and worsen the greenhouse effect.
Until recently, here in Connecticut, we thought we could get electricity
for these air conditioners by splitting atoms in nuclear power plants.
This ensured that electricity continued to become more expensive, and that
we now have large amounts of radioactive waste to store in someone else's
back yard. Or, we can get electricity by burning oil, coal, natural gas or
garbage. All of these sources are expensive, cause air pollution, worsen
the greenhouse effect and consume valuable resources.
We can also get electricity from hydroelectric dams. But, since electric
air conditioning requires so much energy, the only way to get enough is to
build enormous new hydroelectric projects like the one in progress at James
Bay in Northern Canada. The plan is to flood an area the size of France,
making refugees of millions of animals, and native people, while drowning
billions of important plants. The landscape from there to here will be
scarred with high voltage power lines delivering that electricity.
How do electric, non-solar air conditioners work? Simply described, they
move heat from the inside to the outside, making life cooler for some and
hotter for others. But aside from the heat moved, electric air conditioners
are significant sources of heat themselves. All the energy used to turn
motors, fans and compressors ends up in the environment as waste heat. And,
this sad tale doesn't end there. In order to make electricity, two-to-three
times the amount of energy used by the appliance is wasted as heat at the
power plant, warming air and water directly.
If we continue to build glass office towers with sealed windows, malls and
apartments surrounded by asphalt, and big ugly houses in a sea of lawns, we
are doomed to a growing dependency on the world's energy giants. These are
the companies which think that solar air-conditioning means using
expensive, high-tech windmills, photovoltaic cells and concentrating
collectors to produce electricity that is fed to the grid and then sold to
us to run electric air conditioners which have been manufactured by the
Letting the forest grow is a much-more direct and elegant way to cool off.
Do we want a future filled with nuclear power plants and radioactive waste
sites, a future of oil spills, oil shocks and oil wars, a future with huge
areas flooded in sensitive Arctic regions and lots of high voltage
transmission lines---or do we want a future filled with trees and buildings
which are sized and shaped to be cooled by natural processes?
If you stop mowing your lawn, a forest will begin to grow. Plant a few
larger trees to get it going. Use native varieties. Remember to let the
winter sun into your house; evergreen trees, planted to the northwest will
keep your house warmer in the winter. Trees are truly quiet, solar-powered
This is Bill Duesing, Living on the Earth.
(C) 1998, Bill Duesing, Solar Farm Education, Box 135, Stevenson, CT 06491
Bill and Suzanne Duesing operate the Old Solar Farm (raising NOFA/CT
certified organic vegetables) and Solar Farm Education (working on urban
agriculture projects in southern Connecticut and producing "The Politics of
Food" and "Living on the Earth" radio programs). Their collection of essays
Living on the Earth: Eclectic Essays for a Sustainable and Joyful Future
is available from Bill Duesing, Box 135, Stevenson, CT 06491 for $14
postpaid. These essays first appeared on WSHU, public radio from
Fairfield, CT. New essays are posted weekly at http://www.wshu.org/duesing
and those since November 1995 are available there.
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