Global Agribusiness "El Niño and Agribusiness: global weather risks and ..."

Research evidence excerpt

Global Agribusiness "El Niño and Agribusiness: global weather risks and ..."

Global Agribusiness UBS Research

El Niño and Agribusiness: global weather risks and

commodity implications

Technical description

According to NOAA, El Niño is the warm phase of the El Niño-Southern Oscillation

(ENSO), a recurring ocean-atmosphere climate pattern centered in the tropical Pacific

that alternates among El Niño (warm phase), La Niña (cool phase), and ENSO-neutral

conditions. El Niño is associated with anomalously warm sea-surface temperatures

(SST) in the central and eastern equatorial Pacific and can influence weather and climate

patterns around the world.

El Niño is identified when the 3-month running mean of the relative Niño-3.4 SST

anomaly is +0.5°C or greater for at least five consecutive overlapping 3-month seasons.

The relative Niño-3.4 anomaly is calculated by taking the SST anomaly in the Niño-3.4

region and subtracting the average SST anomaly across the global tropics (20°N-20°S).

NOAA emphasizes that in order to characterize an El Niño event the atmosphere must

respond to the oceanic anomaly, typically through a weakening of the easterly trade

winds, shifts in tropical convection and rainfall toward the central/eastern Pacific, and

broader changes in tropical pressure patterns and circulation. This ocean-atmosphere

coupling is essential because it is what links tropical Pacific conditions to global

teleconnections, including changes in storm tracks, precipitation, and temperature

patterns in distant regions.

FigureSource:NOAA1: Niño 3.4 regionNiño

In normal (ENSO-neutral) conditions, strong easterly trade winds push warm surface

waters westward, piling up warm water near Indonesia, while cooler waters dominate

the eastern Pacific near South America.