What phenomenon causes a warming of ocean surface off the western coast of South America every 4 to 12 years?

The phenomenon that causes a warming of ocean surfaces off the western coast of South America every 4 to 12 years is known as El Niño. This climatic event is characterized by the periodic rise in sea surface temperatures in the central and eastern Pacific Ocean. During El Niño, the typical patterns of oceanic and atmospheric circulation are disrupted, leading to significant changes in weather patterns across the globe.

El Niño has profound effects, including increased precipitation in some areas and droughts in others, impacting agriculture, fisheries, and ecosystems. The occurrence of El Niño can lead to various socio-economic impacts, influencing food production and contributing to changes in weather-related disasters.

In contrast, La Niña, which is another climate phenomenon, typically occurs as a cooling of the ocean surface water in the same region, leading to opposite weather effects of El Niño. The term "La Niño" is not widely recognized in the scientific community, and while a tsunami refers to a series of large ocean waves caused by geological disturbances, it is unrelated to atmospheric climate patterns. Thus, El Niño is the phenomenon that aptly describes the warming effect observed in the ocean off the coast of South America over the specified timeframe.