It has been suggested that global warming has caused the El Niño/Southern Oscillation (ENSO) climatic events to become more frequent and intense. However, several ENSO events that occurred before 1880 had effects at least as intense and wide-ranging as those associated with the current event. This is the case particularly for the events in 1396 (ref. 1), 1685-88, 1789-93 and 1877-79. Here I discuss archival evidence, notably from South Asia and above all for the 1789-93 ENSO, for the strength of these historical effects.