La Nina proves as disruptive as her better-known brother

EL NINO, a periodic sloshing of warm water from west to east across the Pacific, gets its name—“the boy child”—because it is around Christmas that it warms the water off Peru. It is now understood to have far wider effects, leading to characteristic patterns of temperature, rainfall and drought around much of the world. El Nino’s female counterpart, La Nina—a cooler sloshing from east to west—is less well known, and less frequent. But it too can impose a distinctive pattern of weather worldwide.

A moderately strong La Nina began around the middle of 2010 and is now at its peak; it is very likely to last another couple of months, and conceivably into the middle of this year. It can be blamed for floods in Australia, which are typical of La Nina in their location, if not their intensity, and in the Philippines, where ten people had died as of January 4th. But these are far from the first symptoms. The torrential rains which killed hundreds in Venezuela and Colombia in November and December had the little girl’s fingerprints on them, too. The spectacular inundation in Pakistan last August also fits the pattern. …