Despite the progress of science we still cannot safely predict the future of the global environment. Any such predictions-let alone the reliability of likely scenarios-are still questioned. And yet it is possible to make ecological forecasts and check on the proposed ideas. The main thing here is to study-proceeding from geological data on biospheric self-regulation- the mechanism of biospheric homeostasis responsible for the steady dynamics of the inner medium when key parameters are close to optimum. In fact sedimentary rock masses are the material products of the vibrant earth mantle, which is an open global dynamic system. Articles of this rubric reflect the authors'opinion. -Ed. стр. 35 BIOSPHERIC RHYTHMS Major global changes in the Phanerozoic. Certainly, failing to learn about the homeostatic (self-regulatory) mechanism of the biosphere we shall not be able to correctly respond to the upcoming nature and climate changes and far less so, to attempt controlling the habitat. As Academician Vladimir Vernadsky (1863 - 1945) wrote: "The biosphere cannot be understood in phenomena occurring within it", if we forget its geological history. However, geology has not addressed this problem as yet, though studying the mechanism of biospheric homeostasis would bring answers to many disputable questions: the causes of the mass extinctions of animals, great glaciations, periodicity of sediment and ore accumulation, and the like. The biosphere, which includes living matter, the hydrosphere, troposphere and the upper part of the lithosphere, has been habitable for about 4 billion years now, though it has changed a lot. As any self-organizing system, it is characterized by homeostasis and to sustain it the biosphere has to make self-excited (self-sustained) oscillations that are recorded in output products, the sedimentary rocks and minerals. Our research into the periodicity of geological processes has allowed to elucidate ... Read more