A Realistic Way to Deal with Global Warming
Global warming, caused by a ring of greenhouse gases (mainly carbon dioxide) surrounding the earth, is, according to experts working on this problem, a threat to the future ability of our planet to support human life. As such, it is the main problem facing mankind, even exceeding the economic and political issues that fill the news on TV, in the newspapers, and on the Internet every day. Thus the question is how to reduce, or at least not to increase, the quantity of such gases, hoping that the current gases will slowly dissipate into outer space.
Human societies require a growing amount of energy every day. This energy cannot continue to be obtained by the use of fossil fuels such as petroleum and coal, as their use produces the greenhouse gases. Actually, all the energy available to us is derived from sunlight; both from the sun shining every day as well as the stored fossil fuels produced by sunlight that reached Earth eons ago. That sunlight supported the growth of vegetation that eventually died and decayed, sinking underground and becoming oil, coal, and "natural" gas.
It is, however, possible to produce power from sunlight without generating greenhouse gases.
One way to do this is by using the sunlight to heat water sufficiently to make steam, using the steam to pump water up behind a conveniently located dam (man-made dams with water storage facilities can be constructed virtually anywhere) and then letting the water down to drive a hydroelectric generator making electricity. With electricity, one can carry out almost any human function by the use of battery-powered cars, trucks, electrically driven trains, and buses.
There are a number of really "clean" power-generating methods, such as wind and wave power and some schemes for extracting power from deep below the Earth's surface. Nuclear power is often mentioned as well, but reactors have noxious residues and it takes power to produce nuclear fuel.
My first publication on this subject appeared in the MIT Faculty Newsletter in 2007. In that paper, I emphasized that what was needed was a complete solution to every part of the problem:
1. The foreign policy problem due to the ability of major petroleum producers to withhold supplies;
2. Global warming made visible by melting ice and rising sea levels, and the arguments of those pushing poor alternative solutions (such as ethanol, a loser from day one). It takes more energy to produce ethanol than it provides and greenhouse gases are still produced when ethanol is used.
Many other alternative solutions have been proposed, but none that is both affordable and complete. In particular, unless we can find a fuel that can be used with the same technology as petroleum is used today (but without noxious residues – clearly impossible) we shall have to rebuild our entire energy structure. While this surely will be very expensive, it is useful to take a long-term view of the problem and concentrate on the eventual operating cost.
3. Sunlight is free. If all our power was derived from sunlight, then we could literally see the light at the end of the tunnel.
The general idea is to collect sun power on giant steerable mirrors in geostationary orbit.
The mirrors are inexpensively constructed as thin plastic balloons, one of the concave surfaces of which is aluminum-coated, the internal pressure adjusting the focal length. A mirror about a mile in diameter would collect about the same amount of power as a typical power plant on earth; and the technology to redirect the light to a fixed position on earth is already used in communication satellites.