Final answer:
Between 1950 and the late 1970s, ENSO favored more frequent and intense El Niño events, which are part of a cycle of warm and cold sea-surface temperatures in the Pacific Ocean affecting global weather patterns.
Step-by-step explanation:
From 1950 to the late 1970s, the state of ENSO was characterized by stronger and more frequent El Niño events. The El Niño Southern Oscillation (ENSO) is a systematic shift in atmospheric pressure, sea-surface temperature, and ocean circulation in the tropical Pacific Ocean that creates cycles of warm and cold temperatures.
During an El Niño event, a band of warm ocean water develops in the central and east-central equatorial Pacific, including off the Pacific coast of South America, leading to high air pressure in the western Pacific and low air pressure in the eastern Pacific.
These events cause global changes in temperature and rainfall, affecting weather patterns and thereby having an impact on agriculture and ecosystems around the world.