LOVELOCK, James (1919- ) - Químico estadounidense. Autor de la hipótesis Gaia, que considera a la Tierra como una entidad viva capaz de alterar la composición de la atmósfera para compensar los efectos desfavorables de los agentes perjudiciales a la vida.

Polémica entrevista con James Lovelock

James Lovelock

English inventor, atmospheric chemist, winner of the 1996 Volvo Environment Prize and the 1997 Asahi Glass Foundation Blue Planet Prize, James Lovelock thinks there may be a closer connection, a coordination between the evolution of life and the evolution of the environment. He calls his theory Gaia (from the Greek goddess of Earth). The theory, described in his 1979 book Gaia (5), can be paraphrased in different ways. In the preface to Gaia, Lovelock himself writes, "...the biosphere is a self-regulating entity with the capacity to keep our planet healthy by controlling the chemical and physical environment." Others have described the theory as the idea that Earth itself acts like a single organism.

Lovelock believes, for example, that Gaia is at work to keep the oxygen content of the atmosphere high and within the range that all oxygen-breathing animals require. The atmospheres of our two nearest neighbors, Venus and Mars, contain 0.00 percent and 0.13 percent, respectively, of free oxygen. Without life to keep supplying it, Earth wouldn't have any either.

Lovelock believes that life regulates the surface temperature of Earth, too. He says the average surface temperature of Earth has remained within a narrow range — between 10 and 20° C — for over three billion years. The temperature, he says, has not varied from the mean by more than 5°C (9° F.) Other research shows that the range could be wider (6), but the constancy of Earth's surface temperature since life became established is still remarkable. During that time the sun's output has increased by thirty (7) or forty (7.1) percent. How has this stability of Earth's temperature been maintained? Even ignoring the long-term trend of the sun, wouldn't the temperature vary more than that? How stable is the temperature on our neighboring planets?

In March 1995, the Hubble Space Telescope "weather center" issued a report containing the following: "The higher temperatures and global dust storms on Mars in the 1970s have ended. The skies are now clear and 36 [Fahrenheit] degrees colder, on average, with morning haze and lingering clouds near the volcanoes" (8). Two years later, when the Hubble telescope was again aimed at Mars, even more dramatic changes were noticed (9):

Abrupt swings that would devastate civilization if they occurred on Earth are routine on Mars, where the global climate can veer from relatively hot, dusty weather to very cold and cloudy within a matter of days.... On Earth, a change in global average temperature of only a degree or so over decades has raised concerns about global warming. On Mars... the temperature can swing by 80 degrees Fahrenheit wthin days.

These reports give strong evidence that a mechanism to keep Earth's surface temperature steady is needed. The fact that Earth's temperature is steady means that the mechanism — whatever it is — is working.



Zona primaria: pensamiento de unidad

Fecha de modificaci�n: 10/12/2005 17:29
Fecha de creaci�n: 06/12/2005 01:17
Compilador: Celia Gradín