Gary Becker y Richard Posner, ambos prestigiosos profesores en la Universidad de Chicago, mantienen un interesante y peculiar blog a donde han trasladado sus columnas editoriales en prensa dándoles el formato de un debate semanal a cuatro manos.
Estos días han discutido sobre la sostenibilidad del crecimiento económico ante la crisis energética y las mejoras en la esperanza de vida de la población. Mientras Becker (On sustainable development) se muestra optimista, Posner (Posner's comment on sustainable growth) es pesimista. Los argumentos de Becker nos recuerdan que los análisis de sostenibilidad basados en exclusiva en la estimación de los stocks de recursos naturales (especialmente aquellos no renovables como el petróleo) son incompletos pues se olvidan de los avances tecnológicos. La tecnología ha incrementado los recursos explotables al hacer accesibles reservas previamente inaccesibles y permitir el descubrimiento de nuevas reservas.
In a simple arithmetical sense, the use of some non-renewable resources in current production clearly reduces the stock remaining for future generations. But the relevant concept for development purposes is not the physical supply of fossil fuels and other non-renewable resources, but the economic cost of gaining access to them. Over most of the past 100 years, fossil fuel prices relative to other prices declined rather than increased, even though significant amounts of these fuels were used to help develop many nations. The reason for the decline in relative prices is that new discoveries and better methods of getting at known sources of oil, gas, and coal led to growing rather than falling stocks of economically accessible reserves.
Por otra parte, Becker defiende que la estimación de crecimiento debería incluir todos los componentes del bienestar humano y no sólo su componente estrictamente económico. Utilizando este tipo de indicadores el aumento de la "riqueza" es mayor y más sostenible dado que la esperanza de vida se ha incrementado drástica y continuamente en el pasado y parece que lo seguirá haciendolo en el futuro.
However, I believe that the most serious deficiency in the usually discussions of "sustainability" is that it should refer to total wellbeing, not simply to what is measured by national income statistics. Even if fossil fuels become increasingly scarce and expensive, and even with further declines in the environment, improvements in health will continue to advance overall measures of wellbeing. Life expectancy has grown enormously during the past half century in virtually all countries, including the poorest ones. Indeed, the typical length of life has generally grown faster in poorer than richer countries as they benefited from medical and other advances in health knowledge produced by the rich nations. The Aids epidemic has set back several African nations, but the increase in life expectancy has been impressive even in most of Africa.
A recent study (see Becker, Philipson, and Soares, "The Quantity and Quality of Life and the Evolution of World Inequality" American Economic Review, March 2005) shows how to combine improvement in life expectancy with traditional measures of the growth in GDP to measure what we call the growth in "full" income. We demonstrate that the growth in full income since 1965 has been much faster than the growth in material income in essentially all countries, but especially in less developed nations. A better measure of full income that adjusts not only for the growth in life expectancy, but also for changes in the environment, and for the great advance in the mental and physical health of those living, especially of the elderly, almost surely grew at an even faster rate.
Todo esto hace que Becker defienda la importancia de los análisis de desarrollo sostenible y que critice a los alarmistas mecanicistas (donde puede que se sitúe Posner) que se olvidan del efecto de la y las mejoras en la calidad de vida:
This is why I believe that while the sustainable development literature asks important questions, the analysis has been inadequate and overly alarmist. Most of the discussion takes a mechanical view of changes in the stock of the stock of non-renewable resources, pays insufficient attention to technological advances in the economy, and gives much too little weight to the enormous advances in health that are highly likely to continue in the future, and possibly even accelerate.
Posner se preocupa por la misma razón que a Becker le alegra: cree que el aumento de población mundial hace que, aunque la riqueza mundial absoluta crezca, la riqueza per cápita tienda a reducirse
My reason for pessimism about the future is connected to Becker's reason for being optimistic! I fear population growth. The combination of increased longevity as a result of medical advances and healthier life styles, reduced infant mortality, and a continued high demand for large families in much of the world seems likely to overcome the "demographic transition," that is, the well-documented negative effect on birth rates of increases in average income to middle-class levels.
Por el contrario, no parece estar demasiado preocupado con la crisis energética, salvo por sus efectos a corto plazo en los mercados:
A very large unforeseen change in the price of an important input such as energy could precipitate a national or global recession because the economy could not adapt instantaneously to such a change.
Los argumentos de Becker están mucho más sustentados por los datos, mientras que Posner parece caer en un cierto alarmismo, pero no rebate los datos de Becker ni proporniona información alternativa. Será que Becker es economista y Posner jurista ... (ninguna de las dos disciplinas se siente obligada habitualmente a ajustarse a la realidad, pero la economía es una ciencia, aunque un poco blanda, y el derecho sería más un arte).
