El Niño And Climate Change Fuel Brazil Floods

Catastrophic flooding in Brazil in April and May was a stark reminder of the compound effect of El Niño and climate change. Unprecedented rainfall led to devastating flooding across Rio Grande do Sul.

Record-breaking rainfall in the Rio Grande do Sul (RGDS) province of Brazil — equivalent to three normal months of rainfall in a two-week period — caused flooding over an area the size of the U.K. (Figure 1).

Two-week rainfall accumulations reached almost 1,000 millimeters in some parts of RGDS, and the state's capital, Porto Alegre, registered 327 millimeters of rainfall in less than a week at the end of April (Figure 2).

The flooding has also been long-lasting, persisting for almost all of May with flood depths reaching 5 meters in some locations.¹ Economic losses are expected to exceed 22 billion Brazilian Reals (US $4 billion).