Complexity and Systemic Models: Tools to understand and manage crises.

We sometimes face critical situations and frequently try to handle them without a good understanding of their complexity. A dissociated and even fragmented approach, often rules in our management of politics, economics, education and business. Only some limited aspects are taken into account, out of context and even omiting sometimes very basic features of the affected entity. When we busy ourselves with the study of systems and their multiple relations with their environment, we should try to discover and use some efficient ways for their management. If we consider systemic modelisation, we notice the existence and multiplicity of hypercomplex entities and situations, mostly man-made or, at least, widely modified and made more complex by human activities. Examples are the vast economic systems for production and distribution of goods, as well as the numerous and very diverse local, national and transnational ones, private or public, concerned with a wide variety of specific subjects, scientific, technical, economical, political, social, etc. Most of those originally natural and more or less cyclical ones (water, forests, soils, human as well as vegetal and animal populations, etc…), have been widely modified by ever increasing human interferences, deepened in turn by technological progress. Obviously, we should urgently attend the need for a better understanding and adequate management of all kinds of complex systems, natural as well as man-modified. This would be possible only through a new conceptual synthesis, in order to gain a general and coherent integration of our enormous, but scattered and globally ill-interconnected specialised knowledge.