More than one-third of the Earth’s surface is made up of the Pacific Ocean, and changes in its temperature in a comparatively small area close to the equator have an impact on weather from the interior of Australia to the Canadian prairies to the agricultural nation of East Africa. El Niño is essentially a periodic warming of tropical Pacific surface waters that causes a series of atmospheric changes that are felt in almost every part of the world, frequently in ways that appear completely unrelated to a patch of warm ocean thousands of kilometers away.
The relationship is instantly recognizable in Australia. Strong El Niño occurrences cause the Australian and Indonesian land masses to receive less rainfall, the bush to dry out, and the risk of fire to increase dramatically. Although drought had been accumulating for years, the 2019–2020 Black Summer fires in Australia happened during El Niño-influenced circumstances. Internal temperatures rise, soil moisture decreases, and the type of terrain that typically allows cattle to graze becomes cracked clay. Reduced rainfall, increased fire danger in peat forests, and the ensuing smoke events that impact Southeast Asia’s air quality for weeks at a time are similar pressures faced by Indonesia and Malaysia.
The monsoon link is very important to India. The rainfall that hundreds of millions of farmers rely on for their growing seasons is diminished during El Niño years due to a reduced Indian monsoon. The yields of rice, wheat, and sugar cane are all negatively impacted by delayed or insufficient rainfall. Rice prices fluctuate, sugar futures vary, and the food security of low-income households in South and Southeast Asia deteriorates in ways that rarely make international headlines but are felt keenly by those on the ground. These agricultural ramifications also have an impact on commodities markets.
Perhaps the most contradictory regional image is found in South America. During El Niño, Peru and Ecuador, which typically have dry Pacific beaches, see drastically increased rainfall. This flooding has historically resulted in major infrastructure damage and the evacuation of coastal residents. During the same time period, conditions are drier than typical in sections of the Amazon basin and northern South America. Rain or drought are not always brought about by the phenomena. They are redistributed.
Those who haven’t studied it attentively often find the storm dimension surprising. Atlantic hurricane activity is suppressed under El Niño circumstances because the warm Pacific seas change the upper atmosphere’s wind shear patterns over the Atlantic, preventing the formation of tropical storms. Strong El Niño years have generally had less active Atlantic hurricane seasons. In contrast, there is an increase in storm activity in the eastern and central Pacific. Instead of a net reduction, it is a redistribution of harmful potential.
El Niño’s most direct connection to the broader climate discourse is the global temperature effect. Elevated global average temperatures are a result of warmer Pacific waters, and when El Niño and the long-term warming trend caused by greenhouse gas accumulation coincide, the combined effect results in record-breaking temperatures that climate scientists identify as important data points. Although El Niño is not the cause of climate change, its periodic amplification of baseline temperatures that are already elevated has made the impacts of previous El Niño events more severe than those of similar phenomena in previous decades.
There’s a sense that the stakes have increased when observing the forecast models as scientists update their El Niño outlooks every month. Governments overseeing agricultural subsidy budgets, insurers, and food planners all monitor the same ENSO indicators and modify their plans appropriately. The phenomenon is cyclical and natural. The environment it enters has undergone significant alteration.
