São Paulo faces heightened flood, fire and drought risk from El Niño

The arrival of the El Niño phenomenon is expected to bring a mix of heavy rain, intense thunderstorms, and prolonged dry periods to São Paulo. In the 24‑hour period ending on 24 June, the city recorded nearly 100 mm of rain—about half the monthly average—an early indication of the amplified high‑altitude jet streams that can shift precipitation patterns. Experts warn that while total annual rainfall may not change markedly, the city could see fewer prolonged light showers and more concentrated downpours, increasing the likelihood of street flooding and water‑course overflow.

Officials of the municipal Climate Change Secretariat have tasked 13 city agencies with submitting flood‑mitigation plans by August, emphasizing measures such as clearing drainage channels and pruning trees. The state government also announced the deployment of artificial‑intelligence tools to analyse meteorological data and a network of highway cameras to detect emerging fire hotspots in forested and agricultural areas. Air‑quality specialists note that smoke from regional burning, including fires in the Amazon and Pantanal, adds fine particulate matter that can exacerbate cardiovascular events, especially among the elderly, pregnant women and children. The combined threat of heat, reduced humidity, and degraded air quality could strain public‑health services as the city moves toward the peak of the El Niño season in September.