Trees are Quiet, Solar-Powered Air Conditioners

by Bill Duesing

First broadcast on WSHU/WSUF-FM, May 8, 1998

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:

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 military-industrial complex.

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 air conditioners.

This is Bill Duesing, Living on the Earth


This page and its contents are copyright © 1998 by WSHU-FM, Fairfield, CT, and by Bill Duesing.