The southward expansion rate of the desertification in the Adamawa Plateau (Central Cameroon): implication for the speed of the Sahel desertification progress in Central Africa

Abstract

Central Africa experiences desertification hazards mostly due to deforestation in context with climate change and human activities like iron melting and agricultural practices. However, one of the most severe obstacles for sustainable development in Central Africa is the Sahel desertification whose speed of progress is underexplored. Among multiple lines of evidence recorded in geological archives, which suggest its southward progress in Central Cameroon over the Anthropocene epoch, the southward shift of the Intertropical Convergence Zone since 3.6 kyr BP is the most warning signal followed by forest disruption in favor of savannah expansion. This project aims at estimating the speed of the Sahel desertification progress in Central Africa, by quantifying its progress rate in Central Cameroon located between the sahelian zone, to the north, and the equatorial zone, to the south. For this purpose, four lake-sediment cores were collected in four shallow lakes on the Adamawa Plateau. They are investigated for sedimentology, geochemistry, mineralogy, and radiocarbon chronology. The goal of this study is to characterize the sedimentary sequences, pinpoint related environmental change in sediment supply and source area and differentiate relevant paleoclimate indicators of intensification of dry conditions over time. The importance of these centennial to decadal natural trends and variations as well as possible effects of human activities will contribute to a better understanding of the Sahel desertification progress in Central Africa.