Final answer:
From 1980 to the present, the state of ENSO has been characterized by stronger and more frequent El Niño events.
Step-by-step explanation:
From 1980 to the present, the state of ENSO has been characterized by stronger and more frequent El Niño events. El Niño is the warm phase of the El Niño Southern Oscillation (ENSO) and occurs when a band of warm ocean water develops in the central and east-central equatorial Pacific, including off the Pacific coast of South America. This phenomenon causes global changes in both temperatures and rainfall.