| Summary: | From 1875-78, concurrent multi-year droughts in Asia, Brazil, and Africa, referred to as the Great Drought, caused widespread crop failures, catalyzing the Global Famine, which had fatalities exceeding 50 million people and long-lasting societal consequences. Observations, paleoclimate reconstructions, and climate model simulations are used to 1) demonstrate the severity and characterize the evolution of drought across different regions, and 2) investigate the underlying mechanisms driving its multi-year persistence. Severe or record-setting droughts occurred on continents in both hemispheres and in multiple seasons, with Monsoon Asia the hardest hit, which experienced the single most intense and the second most expansive drought in the last 800 years. The extreme severity, duration, and extent of this global event is associated with an extraordinary combination of preceding cool tropical Pacific conditions (1870-76), a record breaking El Niño (1877-78), record strong Indian Ocean Dipole (1877) and record warm North Atlantic Ocean (1878) conditions. Composites of historical analogues and two sets of ensemble simulations – one forced with global sea-surface temperatures (SSTs) and another forced with tropical Pacific SSTs - were used to distinguish the role of the extreme conditions in different ocean basins. While the drought in most regions was largely driven by the tropical Pacific SST conditions, an extreme positive phase of the Indian Ocean Dipole and warm North Atlantic SSTs, both likely aided by the strong El Niño in 1877-78, intensified and prolonged droughts in Brazil and Australia respectively and extended the impact to northern and southeastern Africa. Climatic conditions that caused the Great Drought and Global Famine arose from natural variability, and their recurrence, with hydrological impacts intensified by global warming, could again potentially undermine global food security.
|
|---|