Which phenomenon describes a warm ocean current along the equator near Ecuador?

• A. La Niña
• B. The Gulf Stream
• C. The Pacific Decadal Oscillation
• D. El Niño

Answer: (D)

El Niño describes the warming of surface waters in the tropical Pacific Ocean, especially along the equator near Ecuador and Peru. When the trade winds weaken, warm surface water that usually sits in the western Pacific moves eastward, creating a persistent warm pool in the central and eastern Pacific. This warming alters weather patterns around the world, bringing changes like wetter conditions in some regions and drought in others. The Gulf Stream is a warm Atlantic current, La Niña is the cooler counterpart in the Pacific, and the Pacific Decadal Oscillation is a long-term climate pattern that can be warm or cool over decades, not specifically this equatorial warming event.