Is the portrait of the fate of the world economy painted by the Limits to Growth model an accurate one? Because Herman Kahn and his associates did not think so, they presented an alternative vision in a book titled The Next 200 Years: A Scenario for America and the World. 8 This vision is an optimistic one based in large part on the continuing evolution of a form of technological progress that serves to push back the natural limits until they are no longer limiting.
The basic conclusion reached by this study is stated in the opening pages of the book [Herman Kahn, William Brown, and Leon Martel, The Next 200 Years: A Scenario for America and the World (New York: William Morrow, 1976)]: 200 years ago almost everywhere human beings were comparatively few, poor and at the mercy of the forces of nature, and 200 years from now, we expect, almost everywhere they will be numerous, rich and in control of the forces of nature [p. 1].
The future path of population growth is expected by Kahn and his associates to approximate an S-shaped logistic curve. This image suggests that an omniscient observer during 1976 looking backward through time and then forward into the future would see rather different things. The retrospective glance would reveal a period of exponential population growth, while the glance into the future would reveal continued growth, but with steadily declining growth rates, until, at the end of the next 200-year period, growth would automatically come to a halt. By that time, however, the population would have increased four times its current level and the average person in the world economy would be earning $20,000 a year (in constant dollars)—a far cry from the 1976 average of $1300 (see Figure 1.2).
To Kahn and his associates, interference with this natural evolution of society would not only be unwarranted, it would be unethical. As they see it, tampering with the growth process would consign the residents of the poorest developing countries—and, indeed, the poorest residents of the developed countries—to a life of poverty, a life without hope. In contrast, they see continued growth as providing continued betterment for both groups; although, due to an expected decline in the gap between the rich nations and the poor, those in the poorest nations would benefit most from continued growth.
The Kahn model is more qualitative than the Limits to Growth model and therefore its structure is less specific. It is not a computer program that simulates the future. Rather, Kahn and his associates devised scenarios they believed to be plausible and then verified that the various components of these scenarios were consistent with each other. The book is filled with reasons why the chosen scenario is reasonable. These lists of reasons frequently include new technologies that, when certain limits are reached, will be introduced. These technologies effectively either remove the limit or buy time until a subsequent technology can remove the limit.
The principles underlying Kahn's work can best be illustrated through the use of two examples: food and energy. One of the sources of collapse in the Limits of Growth model was the inability of food supply to keep up with consumption. Kahn, by contrast, sees food production rising so rapidly as to create an eventual abundance of food. This vision, in turn, depends on some specific sources of optimism: (1) physical resources will not effectively limit production during the next 200 years, and (2) substantial increases can be expected in conventional foods produced by conventional means, conventional foods produced by unconventional means, and unconventional foods produced by unconventional means.
All of these sources of optimism are related to technological progress. The availability of physical resources can be expanded through the use of better (solar-powered, for example) irrigation systems. Conventional food production can be increased by the spread of better farming techniques and by the development of new hybrid seeds. If soils become depleted or scarce, then food can be raised with hydroponics, a process using no soil. 9 Finally, Kahn points to the development of a single-cell protein as a viable means of converting municipal waste into a food supplement.
A similar approach is taken when describing the world energy future. The authors of The Next 200 Years construct a list of technologies that can provide the transition to solar energy, making the case that solar energy can ultimately sustain a high level of economic activity. The list includes technologies that use coal, either directly or indirectly (such as gas produced from coal); those which exploit the vast world reserves of shale oil; nuclear power (fission, in the near term, replaced subsequently by fusion); and new solar technologies including windmills, photovoltaics, and ocean thermal power.
When all of these lists are combined, the prevailing message is that currently recognized technologies can overcome the limitations envisioned by the Limits to Growth view. The Next 200 Years staff, then, believes that the creators of Limits to Growth erred in being myopic; they were too tied to conventional technologies. When the need arises, they argue, these new technologies will be developed. The cliche, "Necessity is the mother of invention," captures the flavor of the belief of Kahn and his associates that these technologies will be developed as they are needed. [p.p. 4-11]
Created on ... janvier 16, 2006 by Pierre Ratcliffe