Final answer:
ENSO, particularly its warm phase known as El Niño, has significantly contributed to the accelerated retreat of tropical Andean glaciers since the late 1970s, with climate change intensifying these effects.
Step-by-step explanation:
The phenomenon of ENSO (El Niño Southern Oscillation) has been identified as a driving factor in the acceleration of tropical Andean glacier retreat since the late 1970s. ENSO is a systematic shift in atmospheric pressure, sea-surface temperature, and ocean circulation in the tropical Pacific Ocean, which causes alternating warm (El Niño) and cool (La Niña) conditions, leading to global changes in both temperatures and rainfall. El Niño events, characterized by warmer ocean water and lower air pressure in the eastern Pacific, are particularly influential in accelerating the melting of glaciers. However, the complex interaction between ENSO cycles and climate change, which is driven by factors such as the industrial revolution's increase in atmospheric carbon dioxide, has exacerbated the decline of Andean glaciers in recent decades.