La Gazzetta Online

CMCC Lectures  

Late 20th century Sahel drought:

An obvious candidate for attribution?

6 May 2025, 12:00 CEST

An in-depth look at the evolving scientific understanding of the Sahel drought with Alessandra Giannini from École normale supérieure – PSL & IPSL, a leading voice in climate research whose work has reshaped the interpretation of recent droughts in the region, linking them to the warming of global tropical oceans.

 

Join the discussion on drought attribution and gain valuable insight into how unravelling Earth’s system dynamics behind past events in global climate hotspots  is crucial to steering human development toward adaptation in a warming world. 

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 onset of the drought. The region has faced severe droughts throughout history, with one of the most intense episodes occurring in the 1970s. According to NOAA, rainfall during this period dropped by 30% compared to the 1950s, leading to extreme dry conditions causing widespread famine.

 

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.

 

As early as the 1970s, a debate emerged between proponents of local and global causes. Most notably, Charney highlighted a biogeophysical feedback between the human-induced land degradation and a reduction in precipitation and vegetation, while Bryson called into question the global impact of human activity. Once 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 came to the forefront.

 

Alessandra Giannini has played a pivotal role in reshaping the scientific understanding of these recent Sahel droughts and their attribution to the warming of global tropical oceans. As a distinguished guest of the CMCC Lecture Series, she will explore this scientific trajectory and its implications for future climate projections and adaptation efforts.

JOIN THE LECTURE, BE INSPIRED!

Speaker: Alessandra Giannini is a distinguished climate scientist with a background in physics from the University of Milan and Earth and environmental sciences from Columbia University. Her research initially focused on climate predictability in semi-arid tropical regions such as the Caribbean and the Brazilian Nordeste, areas that are profoundly influenced by the El Nino-Southern Oscillation—the most important pattern of climate variability globally. Since conclusively demonstrating, in 2003, the oceanic origin of the great Sahelian droughts of the 1970s and 1980s, her work has focused on this region, that she has travelled extensively, notably, participating in the regional climate outlook fora convened annually around seasonal prediction. Currently, she serves as a faculty member in the Geosciences Department at l’École Normale Supérieure in Paris, France, where she also directs the Center for Education and Research on the Environment and Society (CERES).

Moderator: Anna Pirani, CMCC

The event is part of the CMCC Lectures webinar series, which presents frontier topics and solutions in climate sciences and action, through the insights of leading experts. The series provides a platform for distinguished scientists to showcase their cutting-edge research and engage in dialogue with peers and stakeholders.