La Niña
The cold phase of ENSO: cooler-than-average Pacific Ocean temperatures that strengthen trade winds, intensify the Walker Circulation, and drive drought across South America, East Africa, and South Asia while delivering floods to Australia and Southeast Asia.
What is La Niña?
La Niña occurs when sea surface temperatures in the Niño 3.4 region fall 0.5°C or more below the long-term average. This cooling strengthens the trade winds, pushes warm water further into the western Pacific, and intensifies the Walker Circulation — increasing rainfall in Southeast Asia and Australia while suppressing it in South America, East Africa, and parts of South Asia. La Niña events are often more economically damaging than El Niño for global food security, because they simultaneously stress three of the world's most important agricultural production zones.
Agricultural and Commodity Impacts
Commodity Market Effects
La Niña events are historically the most disruptive ENSO phase for global agricultural commodity markets because they simultaneously reduce production in Argentina (soybeans, corn), East Africa (cereals, coffee), and South Asia (wheat, rice) while creating logistical disruptions in Australia and Southeast Asia.
- Soybeans: −45% Argentine harvest in 2022–23 La Niña — largest single-event supply shock in 20 years
- Wheat: Australia and Pakistan production disrupted simultaneously in same La Niña events
- Rice: Pakistan 2022 floods destroyed 3.8 million hectares of standing rice crop
- Coffee: East Africa double and triple La Niña droughts reduced supply from Kenya, Ethiopia, Tanzania
- Corn: Argentine Pampas drought reduces production alongside weakened South African harvest
Food Security Implications
La Niña is the dominant driver of food security crises in East Africa, the Horn of Africa, and parts of Southern Africa. The triple-dip La Niña event of 2020–2023 was the longest since the 1950s and drove IPC Phase 4 Emergency or Phase 5 Famine conditions across Somalia, Ethiopia, Kenya, and South Sudan for three consecutive years. An estimated 40 million people in East Africa faced acute food insecurity at the peak of the 2023 crisis.
How We Track It
El Niño One Wave monitors the ONI index using NOAA CPC data updated monthly. The live platform shows the current ENSO phase, the 11-year ONI chart, and real-time agricultural temperature anomalies across 6 global monitoring regions that allow early detection of ENSO-phase crop stress.
Full methodology: elnino-onewave.pages.dev/methodology