Atmosphere Ocean Science Colloquium

Late 20th century Sahel drought: an obvious candidate for attribution?

Speaker: Professor Alessandra Giannini, École Normale Supérieure

Location: Warren Weaver Hall 1302

Date: Wednesday, February 28, 2024, 3:30 p.m.


Discussion around the causes of persistent drought in the Sahel, the semi-arid southern margin of the Sahara desert, has fascinated not only climate scientists since the drought's inception in the early 1970s. That a shift in the climate had happened, perhaps magnified by comparison to the anomalously abundant rainfall of the immediately preceding period, became clear early on. Already in the early 1970s the debate raged between proponents of local and global causes. Most notably, Charney spoke of a biogeophysical feedback between the [human-induced] baring of the soils and a reduction in precipitation and vegetation, while Bryson called into question the global impact of human activity. Once that improvements in climate modeling enabled the simulation of this long-term shift, between the wet 1950s and 1960s and the dry 1970s and 1980s, and its attribution to oceanic influence, the classic question of attribution, to human emissions, reached the forefront. I will discuss this trajectory, as well as what it means to projections of future change and adaptation efforts.