There is presently an inadequate understanding of the complex, subtle and often synergistic interactions between the several parts of the geosphere and biosphere. More knowledge is needed for societal management of the global ecosystem to enhance biological productivity and to respond to the increasing needs of a growing population. No single part of the earth -- oceans, atmosphere, biota or human systems -- can any longer be studied and understood in isolation and with sufficient depth to anticipate and deal with changes of the scale now anticipated. Nor can any geographic segment be analysed satisfactorily as an independent or isolated system. There are an insufficient number of national and international programmes which illuminate the processes that govern the behaviour of the oceans, atmosphere, lithosphere, biosphere and the solar terrestrial domain by addressing the interfaces among them. A holistic approach will require several years of careful planning and conceptualization to develop an appropriate scientific strategy. A question yet to be looked at in detail is the extent to which it will be desirable to integrate major international programmes in sciences into an emerging activity focused on global change and, equally, the extent to which the scientific community can re-orient itself and give overriding priority to truly interdisciplinary studies. It can be anticipated that the adjustments called for will have the effect of blurring somewhat the distinctions between large-scale and small-scale science and between what are often referred to as basic and applied forms of scientific research.
Global change in the terrestrial environment (geosphere) and the life that inhabits it (biosphere) is a closely coupled system. The system is constantly undergoing change on time scales that range from hundred of millions of years through the slow recurrence of ice ages to transient phenomena. Changes in the geosphere that embrace the land, oceans, atmosphere and the solar terrestrial domain, and in the terrestrial and marine biosphere, arise from the interplay of physical, chemical and biological processes. Over millions of years these natural changes have resulted in the evolution of delicately balanced ecosystems that constitute the global life support system. To an increasing extent, these changes are influenced by the impact of human activity.