The problem is, by now, widely known: The world faces a potential catastrophe, which will give little warning before it strikes.
It is the irreversible damage to our biosphere from the greenhouse effect. Every year more than 5,000 megatons of carbon dioxide, nearly all from the burning of fossil fuels, escape into the atmosphere. That is far more than can be absorbed by the growth of trees and other plants. In the past 30 years, the burning of fossil fuels has raised the concentration of carbon dioxide in the atmosphere by 10%. A temperate climate depends on the radiating of excess heat through the Earth’s atmosphere. But carbon dioxide traps heat. On our neighboring planet of Venus, the greenhouse effect has gone wild. There, a carbon dioxide atmosphere keeps the surface temperature above 800 degrees, hot enough to melt lead.
There is a solution to the problem if nations act cooperatively, something they have proven they can do if disaster is the alternative.
Reducing our energy usage is not an option, because the production of goods and services is dependent on maintaining an adequate energy supply. The least-developed industrial nations use only one-hundredth as much energy per capita as the most developed, but suffer a living standard a hundred times lower in consequence. Therefore, we could not reduce energy usage without condemning the majority of the world to unending poverty.
Maintaining the present rate of energy growth in developing nations would require that we generate more than five times the energy in 2039 that we do now. Obtaining it from fossil fuels would raise the global temperature drastically, flood coastal areas and reduce already acutely scarce supplies of fresh water.
A worldwide program, over perhaps a period of 50 years, is needed to convert to clean, renewable sources of energy. Energy used at fixed sites--for industries and homes--can be electric, generated without burning fossil fuels. It is harder to wean transportation, which consumes 25% of all the energy we use, from gasoline and diesel fuel. But fuels like methane, propane and butane can be synthesized using recycled carbon dioxide to put energy into portable form. This becomes practical when central-station electric costs are reduced substantially.
In viewing the alternatives for generating energy without the burning of fossil fuels, we must understand the magnitude of future needs. If nuclear power were to provide all the energy the world needs by the year 2039, there would have to be 63,000 nuclear reactors in operation. The examples of Three Mile Island and Chernobyl will not be forgotten quickly and thus make such an alternative unacceptable to many people. Ground-based solar power cannot be generated in the quantity needed without paving much of the world with solar cells. That would further raise the Earth’s temperature by increasing the heat that the ground absorbs. Obtaining power from the temperature difference between surface and deep waters in the tropical oceans would change the global climate profoundly by altering the heat balance at the ocean’s surface.
So a fully acceptable system for generating energy must add little to the Earth’s heat load, burn no fossil fuels and avoid nuclear fission or fusion. There is only one method that satisfies all these conditions--the conversion of solar energy to electric power in high orbit, where sunlight is intense and continuous.
Twenty years of study and experiments confirm that power in high orbit can be sent efficiently to Earth as low-density radio waves. Antennas in fenced-off regions can transform the radio waves to ordinary electricity. Since more than 90% of the radio-wave energy is converted to electricity, almost no waste heat need be released to the environment. No fuels are required, fossil or nuclear.
A decade of study and experimentation by government agencies and private foundations confirms that satellite solar power is environmentally benign. It can compete economically with coal-fired and nuclear-power plants if we can avoid having to haul materials out of the Earth’s strong gravity. Materials for the power satellites--metals, silicon and oxygen--can come from the moon, whose gravitational grip is less than a twentieth of the Earth’s. Those materials are the most abundant elements of the lunar surface and can be mined using known space technology.
The Soviet Union and Japan are particularly aggressive now in working toward satellite solar power. A commercial multi-nation program, modeled on the successful Intelsat and Inmarsat consortia that provide satellite communications, would earn revenues of $250 billion a year, satisfying today’s needs for new electric generators. To meet all the energy needs of 2039, the market would be more than $6 trillion a year annually (in today’s dollars), larger than America’s present gross national product. We as a nation cannot afford to be left out of a commercial program with so huge an export market. Above all, we who live in the biosphere cannot let it die.