Planet Earth: Part III: Biosphere interactions



The qualitative aspects of the interactions between the Earth's biosphere and the physical and chemical components of the global climate system have been understood for some time, but only recently has coordinated study focused on the quantitative nature of these relationships. This study is motivated mainly by concern about our current inability to predict the possible consequences of global change.

The main interactions between the biosphere and climate range from biophysically controlled exchanges of radiation, heat, matter (both CO2 and H2O), and momentum, down to longer time-scale exchanges of chemical constituents that ultimately determine the composition and chemical stability of the Earth's atmosphere and oceans. Ranked in order of increasing time scale (and increasing difficulty of interpretation), these interactions are energy and water cycles, the carbon cycle, nutrients and atmospheric chemistry, and the joint physical and chemical evolution of the atmosphere and the biosphere.