Jean-Paul Bravard – författare

The Earth’s oceans are currently undergoing unprecedented changes: rivers have suffered a severe reduction in their sediment transport, and as a result, sediment input to the oceans has dropped lower than ever before. These inputs have varied over millennia as a result of both natural occurrences and human actions, such as the building of dams and the extraction of materials from riverbeds. Sedimentary Crisis at the Global Scale 1 examines how river basins have been affected by the sedimentary crises of various historical epochs. By studying global balances, it provides insights into the profound disruption of the solid transport of fluvial bodies. The book also explores studies of various rivers, from the Amazon, which remains relatively unaffected, to dying rivers such as the Colorado and the Nile.

The great deltas of the globe have been threatened for several decades but their decline now appears to be inevitable; they are receding and losing the fertility that supports their tens of millions of inhabitants. Our deltas are victims of the dramatic deterioration in the volume of continental sediment brought by rivers to the oceans.By nature, deltas are fragile eco- and geological organisms. For centuries, they have been subject to human actions in the Mediterranean and European world, and today a deep crisis is affecting the great tropical deltas. A chapter is also devoted to concerns facing the Mississippi, an “aging delta of the new world”.Sedimentary Crisis at the Global Scale 2 discusses possible strategies to protect the deltas of the world – or at least adapt them and their dependencies to the changes they face. Several models are possible, including comprehensive protection (such as in the Netherlands) and cautious and respectful opening to the forces of the oceans in an environment-first perspective.