Introduction

The global environmental agenda appears more complex than ever before. There has been a distinct shift in environmental problems from localized disruptions to long-term potentially catastrophic changes at regional and global scales. There is also a growing awareness of the complex interlinkages between the various parts of the physical environment and human actions.

The United Nations Conference on the Human Environment held in Stockholm, Sweden, in 1972 showed just the beginnings of a more marked awareness of the emerging environmental problems and led to, for example, the creation of ministries for the environment in many countries. The United Nations Conference on Environment and Development (UNCED) in Rio de Janeiro, Brazil, in 1992 brought to the forefront the challenges of sustainable development and the urgent need for active international cooperation. The responses, as outlined in the Agenda 21 emanating from UNCED and its scientific counterpart, Ascend 21, prepared by the International Council of Scientific Unions (ICSU), require concerted efforts at national, regional, and global scales. It is no longer enough to "think globally and act locally"; it is also increasingly necessary, while continuing to work at a local level, to begin to "act globally."

The aim of this paper is to outline the responses of the international scientific community to the challenges posed by global environmental change, with particular emphasis on Africa, and to discuss the role and future outlook of such scientific cooperation. The paper focuses on the main global change programmes - the International Geosphere-Biosphere Programme (IGBP) and the Human Dimensions of Global Environmental Change Programme (HDP) -as well as the environmental programme area of the United Nations University (UNU).