El Niño is combining with climate change to drive extreme weather conditions around the globe.
From starving cattle in parched El Salvador to a "terrifying" threat to the world's coral reefs, this year's exceptionally strong El Niño is being felt across the globe.
ADVERTISEMENT
ADVERTISEMENT
The natural weather phenomenon occurs when sea temperatures in the Eastern Pacific Ocean become unusually warm, which happens roughly every two to seven years.
Previous El Niño events have contributed towards record-breaking heat, fuelling long-standing droughts, flash floods and deadly wildfires across the globe.
While most El Niño events increase global average temperatures by around 0.2°C – enough to trigger extreme weather across the Global South – it is a fraction of the additional human-caused warming from climate change.
Here is how this year's so-called 'Super El Niño' is playing out around the world.
El Niño threatens coral reefs and forests
This year's El Niño adds "a terrifying level of additional risk" for the world's coral reefs, according to David Obura, chair of the UN's expert nature panel.
Corals are highly sensitive to heat, and climate change is already making bleaching events more frequent and intense.
The fourth global bleaching event and this year's El Niño have put corals in even greater jeopardy.
Obura led a major reassessment of coral health, published in the science journal Nature, that found reef-building species had deteriorated sharply since the last global census in 2008, with 44 per cent threatened with extinction.
Forests are also at risk. Global deforestation slowed last year, according to the independent Forest Declaration Assessment, but the gains are unlikely to last as conditions worsen in Central Africa and El Niño raises fire risks across the tropics.
Livestock suffer as drought strikes El Salvador
Drought fuelled by El Niño is wreaking havoc across Central America's Dry Corridor, which stretches from Mexico to Panama.
In El Salvador, where August temperatures were 4.3°C above normal, livestock are suffering the impacts.
"Imagine how thin this little animal is! Why? Because of a lack of grass," says Antonio Aguilar, a 54-year-old rancher, pointing to a cow reduced to skin and bones at a livestock market in Sensuntepeque.
The El Niño, expected to peak by year's end, is unfolding amid accelerating human-caused warming, which amplifies its effects. A warmer atmosphere dries out soil, deepening drought, and holds more moisture, making rains more extreme.
Heavy rain closes Iguazu Falls
Extreme downpours fuelled by El Niño caused the Iguazu River to flow at six times the normal rate last week. Park authorities in Argentina responded by closing tourist trails, including the walkway to the Devil’s Throat, the largest and most dramatic of the Iguazu Falls' cascades.
South America, the southern US, East Africa and Central Asia have all experienced heightened flood risks during previous El Niño events.
In Argentina's northeast, tthe Paraná River rose to a dangerous 4.7 metres on 15 October, prompting evacuations in nearby towns. Flooding has also forced thousands from their homes in Paraguay and Uruguay.
Global poverty risks stoked by extreme weather
UN development chief Alexander De Croo warns that El Niño, combined with surging energy costs and higher interest rates, could push millions into poverty as the vulnerable are hit by crisis after crisis.
In particular, severe drought linked to El Niño is affecting more than half of Sudan – where conflict is already fuelling famine – causing localised crop failures and depriving households of food and income.
Many staple imports, such as maize and beans, could also put Europe's food security at risk, according to the IHE Delft Institute for Water Education in the Netherlands.
While El Niño is out of our control, human-caused warming can be minimised by cutting emissions. De Croo urges private investors to recognise both the "economic cost" of climate change and the "business case" for tackling it.
Sri Lanka's central bank warns that El Niño could undermine the island's fragile recovery from its worst economic crisis in decades, with torrential rains forecast through December and prolonged drought early next year.
Will this year's El Niño be record-breaking?
How this El Niño ranks depends on how it is measured, and agencies' differing methods make direct comparisons difficult.
Britain's Met Office calls it "unprecedented" and Japan's weather agency calls it the strongest ever observed, but US forecasters have not declared a record – yet.
The strongest El Niño year in NOAA's dataset is 1982. The agency says the current event will likely surpass it.
"By any measure, we are looking at a very strong El Niño," says climate scientist Emily Becker of the University of Miami. She adds that only once it is over will scientists know "where it fits in the context of history".
Because climate change is warming oceans everywhere, the US National Oceanic and Atmospheric Administration (NOAA) now measures how warm or cool the east-central Pacific is compared with the rest of the tropical ocean. That difference is what drives global weather impacts.
How do a few degrees of warming in the Pacific exert so much influence?
Under NOAA's updated index, a 2.5°C anomaly in a key Pacific region relative to the rest of the tropical ocean, sustained over three months, would make for the most intense El Niño on record.
That might not sound like much, but the El Niño-Southern Oscillation is the leading natural driver of year-to-year climate variability.
Shifts in where the ocean releases heat into the atmosphere ripple across global weather, leaving some regions cooler and wetter and others hotter and drier. These effects are known as "teleconnections".
But while El Niños, and their opposite number La Niñas, when the equatorial Pacific is colder than normal, load the dice toward certain outcomes, they do not guarantee them.
