Warm current (2,4)
I believe the answer is:
el nino
'warm current' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for el nino that I've seen before include "modern opera" , "Periodic warming of the eastern Pacific Ocean" , "Pacific climatic feature" , "Warm current affecting world's climate" , "Pacific climatic effect" .)