A Study Conference on “Geosphere-Biosphere Interactions and Climate” was held at the Pontifical Academy of Sciences, 9-13 November 1998. The purpose of the Study Conference was to examine the role of the biogeochemical cycles and climate, to identify the key scientific issues in this field of research, and to outline a long-term scientific strategy.

Biogeochemical cycles play a key role in the way the Earth's climate both influences and is influenced by interactions with the geosphere and the biosphere. It is probably no overstatement to say that the elucidation of the biogeochemical cycles in Nature constitutes one of the greatest scientific challenges of our time.

The greenhouse gases – carbon dioxide, methane, nitrous oxide, and so on – together with aerosol particles, albeit in tiny concentrations, play a crucial role in determining the Earth's climate. Their concentrations are determined by physical, chemical, and biological processes in the terrestrial and oceanic biospheres and in the ocean as well as by chemical interactions within the atmosphere itself. Thus, to discover how atmospheric trace gas composition is regulated requires an understanding of the complex interactive system that sustains life on Earth, in the face of variations imposed both externally (e.g., orbital variations and changes in the solar irradiation) and by human activities, such as fossil fuel burning, deforestation, and agricultural practices.

Research during recent decades has shown that the climate of the Earth, interacting with chemical processes occurring within the atmosphere and the biosphere, constitutes a complex interwoven and integrated system.