CARBON-DIOXIDE WARMING OF THE EARLY EARTH

Svante Arrhenius' research in atmospheric physics extended beyond the recent past and the near future states of the Earth, which today are a t the center of sociopolitical attention. His plan encompassed all of the physical phenomena known at the time to relate to the formation an d evolution of stars and planets. His two-volume textbook on cosmic ph ysics is a comprehensive synopsis of the field. The inquiry into the p ossible cause of the ice ages and the theory of selective wavelength f ilter control led Arrhenius to consider the surface states of the othe r terrestial planets, and of the ancient Earth before it had been modi fied by the emergence of life. The rapid escape of hydrogen and the eq uilibration with igneous rocks required that carbon in the early atmos phere prevailed mainly in oxidized form as carbon dioxide, together wi th other photoactive gases exerting a greenhouse effect orders of magn itude larger than in our present atmosphere. This effect, together wit h the ensuing chemical processes, would have set the conditions for li fe to evolve on our planet, seeded from spores spreading through an in finite Universe, and propelled, as Arrhenius thought, by stellar radia tion pressure.