Research spanning over a century of data shows El Niño summers linked to heavier downpours, challenging long-held assumptions about drought patterns

El Niño events, traditionally associated with drought in India, are now found to paradoxically intensify episodes of extreme daily rainfall, according to a new study published in journal “Science” on 18 September. Drawing on daily rainfall records of the India Meteorological Department (IMD) from 1901 to 2020, the research team observed that El Niño summers are increasingly marked by heavier downpours, even as total seasonal rainfall often declines.

“This is partly driven by increases in extreme daily values of convective buoyancy, provided that both the undilute instability of near-surface air and the dilution by mixing with drier air above are considered,” the study explained.

Spencer A Hill, lead author from City College of New York, noted: “You tend to get more days with extreme amounts of rainfall within India, not less, in El Niño summers.” He added that the findings run counter to more than a century of conventional understanding that El Niño conditions promote drought by suppressing monsoon rainfall.

El Niño and the Indian Monsoon
El Niño refers to the warming of sea surface temperatures in the eastern equatorial Pacific Ocean, typically 0.5°C or more above the long-term average, accompanied by weaker eastward trade winds. While the phenomenon influences rainfall worldwide, its role in shaping the Indian monsoon has long been considered primarily negative.

The study highlights that the summer monsoon’s interannual variability is driven by multiple factors beyond El Niño, including the Indian Ocean Dipole (IOD), North Atlantic Oscillation (NAO), Pacific Decadal Oscillation (PDO), and Atlantic Sea surface temperature (SST) anomalies. Local conditions such as dust concentrations and agricultural water use also influence rainfall patterns.

Implications for Climate Planning
India’s dependence on the summer monsoon for agriculture, water security and energy supply makes these findings significant for policy and planning. While overall monsoon totals may still decline under El Niño conditions, the rise in intense downpours raises fresh challenges in managing floods, soil erosion and urban infrastructure resilience.

The research underscores the need to reassess how climate variability is factored into India’s adaptation strategies, with extreme rainfall events now becoming a more prominent risk alongside traditional concerns of drought.