Climate change worsened rains and floods which killed dozens in southern Africa, study shows

Weeks of punishing rainfall across southern Africa pushed rivers over their banks and turned streets into torrents, leaving more than 100 people dead and forcing over 300,000 from their homes. A new analysis indicates the deluge was not just bad luck: human-driven warming made the rain more intense and the flooding more destructive.

Scientists working with World Weather Attribution examined the sequence of storms that soaked South Africa, Mozambique, and Zimbabwe and concluded that parts of the region received roughly a year’s worth of precipitation in just 10 days. The resulting floods ripped up roads and bridges, swamped entire neighborhoods, and caused damage running into the millions of dollars.

In Mozambique, entire blocks were swallowed by rising waters; in South Africa’s Limpopo and Mpumalanga provinces and areas of Zimbabwe, critical infrastructure was swept away. The humanitarian toll is still being counted as communities begin a long recovery.

Rainfall beyond design limits in a warmer world

By historical yardsticks, the event aligns with what would once be expected roughly every half-century. But the study found a clear shift toward more violent downpours in the region, a hallmark of climate change: a warmer atmosphere holds and releases more moisture. The ongoing La Niña phase, which naturally tilts southern Africa toward wetter conditions, played a role—but operated in an atmosphere heated by human emissions, amplifying the outcome.

Researchers noted that climate models struggled to assign an exact figure to the boost from warming, reflecting limitations in how well global tools capture local dynamics. Even so, they reported that an increase on the order of 40% in rainfall intensity is difficult to explain without the influence of greenhouse gases. In other words, a stormy spell that might have been serious under past conditions was escalated into a far more hazardous disaster.

Forecasts helped; river realities overwhelmed

Heavy rain and flood risks are not new to southern Africa, yet the scale of this event surprised many specialists. Meteorologists in Mozambique observed that some locations recorded in two or three days what they usually expect over an entire rainy season—volumes no drainage system or levee can easily handle.

Mozambique’s geography compounded the crisis. The country sits downstream of nine international river systems, so local rainfall coincided with surges from upstream catchments. Even with timely forecasts and multiple models signaling danger, the sheer volume of water left little room to prevent widespread damage.

The central and southern provinces were hardest hit. The Gaza provincial capital, Xai-Xai, and the nearby town of Chokwe were largely inundated. In neighboring countries, washouts and bridge failures severed transport links, hampering relief and recovery operations.

Closing the gap: climate models built for Africa

Attribution science aims to quantify how much climate change alters the odds or severity of specific weather extremes. But the researchers stressed a persistent blind spot: most freely available climate models are developed in Europe, North America, or parts of Asia. Those tools tend to perform best in the regions they were designed for, leaving African contexts under-resolved.

Climate experts called for investment in African-led modeling efforts to better capture local terrain, land-atmosphere interactions, and river basin dynamics. Improved regional models would sharpen estimates of how much warming intensified this event, and, crucially, inform planning for flood defenses, zoning, and emergency response across diverse African climates.

From evidence to action

The findings add to a growing body of evidence that a warmer climate is loading the dice toward heavier cloudbursts and flashier floods. As extreme rainfall sharpens, countries will need to rethink standards for bridges, culverts, and stormwater systems; keep new development out of high-risk floodplains; and expand early warning systems that reach the most vulnerable communities.

Cross-border cooperation on river management—covering reservoirs, floodgates, and data sharing—is another priority in transboundary basins. And while adaptation can blunt the damage from today’s hazards, the researchers emphasized that curbing fossil fuel use remains essential to limiting further intensification of extreme rainfall in the decades ahead.