El Niño increases risk of extreme monsoon downpours in India

El Niño, the climate phenomenon known for suppressing India’s summer monsoon rainfall, may paradoxically increase the risk of extreme downpours in the country’s wetter regions, according to a new study.

Researchers analysed more than a century of high-resolution Indian rainfall data, from 1901 to 2020, and found that while light and moderate rainfall becomes less frequent during El Niño years, very heavy daily rains can become more than 50% likelier in already wet areas.

This means that, even as the overall monsoon season is drier, the storms that do occur are often more intense, creating potentially hazardous conditions.

The team, led by Spencer Hill, linked these extreme events to changes in atmospheric buoyancy and shifts in low-pressure system tracks. Unlike the weakening effect of El Niño on India’s average summer rainfall in recent decades, its influence on extreme downpours has remained relatively stable, though regional patterns have shifted.

The findings underline the complex and regionally varied impacts of El Niño on India’s monsoon and suggest that similar processes could drive extreme rainfall variability in other tropical regions/