Final answer:
El Niño is the term describing a change in surface currents causing warmer temperatures on the coasts of South America. It is the warm phase of the El Niño Southern Oscillation (ENSO) and affects global temperatures and rainfall patterns.
Step-by-step explanation:
The term describing a change in the surface currents causing warmer than normal temperatures on the Peruvian and Chilean coasts of South America is El Niño. El Niño is the warm phase of the El Niño Southern Oscillation (ENSO), characterized by a band of warm ocean water in the central and east-central equatorial Pacific.
This phenomenon affects global temperatures and rainfall patterns, and it is associated with high air pressure in the western Pacific and low air pressure in the eastern Pacific.