Final answer:
El Niño and La Niña are inter-annual climate variations associated with changes in sea-surface temperatures and atmospheric pressure in the tropical Pacific Ocean, affecting global weather patterns and having economic impacts.
Step-by-step explanation:
El Niño and La Niña are inter-annual variations in Earth's climate system occurring in the tropical Pacific Ocean. These phenomena represent the warm and cool phases, respectively, of the El Niño Southern Oscillation (ENSO), which have profound effects on global weather patterns. El Niño is characterized by unusually warm sea-surface temperatures in the central and eastern equatorial Pacific, whereas La Niña features cooler than average sea-surface temperatures. Both conditions are linked with shifts in atmospheric pressure across the Pacific, leading to significant changes in climate, such as altered rainfall distribution and extreme weather events.
These events can have economic impacts, especially on agriculture and fisheries, and the potential to induce natural hazards like droughts, floods, and fires. The ENSO cycle is a natural climate pattern, but its intensity and frequency may be influenced by global climate change. Thus, understanding El Niño and La Niña is essential for preparing and mitigating their societal and environmental effects.