The fastest climate switch on record
The numbers are no longer ambiguous. Earth Sciences New Zealand puts the probability of a strong El Niño classification by spring at greater than 60%, while combined NOAA and domestic forecasts push the overall 2026 likelihood above 90%. Rural News Group analysis gives a 33% chance the event reaches strong intensity by year-end, and NOAA gives a one-in-four chance of very strong conditions comparable to the super events of 1997-98 and 1982-83.
What makes this event different is speed. MetService meteorologist Jon Tunster has said there are very few historical analogues for a switch this rapid, with only 1976 and 2023-24 offering comparable precedents. Subsurface temperatures in the central equatorial Pacific are running 3-5°C above average at 100-200 metre depths, paralleling the early stages of the severe 1997 event.
Associate Professor Daniel Kingston from the University of Otago noted in April that if the event unfolds as predicted, impacts may be substantial, adding that the biggest recent jumps in global mean temperature have been associated with El Niño years.
$62 billion in exports built on the wrong weather assumption
Here is the planning failure in one sentence. MPI’s December 2025 SOPI report forecast New Zealand’s primary industry exports would grow to $62.0 billion by 30 June 2026, up from a record $60.4 billion in the prior year. Those forecasts were built under La Niña assumptions. The SOPI explicitly noted La Niña conditions were expected through January 2026. The world has since moved in the opposite direction, and MPI has not revised its numbers.
The sector breakdown makes the exposure concrete: dairy at $27.4 billion, meat and wool at $13.2 billion, horticulture at $9.2 billion. In 2015, Treasury modelling found a 70% probability of drought given El Niño conditions and estimated a 3-5% milk production decline as a realistic scenario, rising to 7-10% in drought-affected years. Reserve Bank research cited in the same 2015 document estimated a severe drought could reduce annual real GDP by 0.3-0.6%.
Those figures are a decade old, but they remain the most detailed official modelling New Zealand has. The most exposed regions are Marlborough, Hawke’s Bay, Canterbury and Northland, where dryland farming, horticulture and wine production concentrate.
The grid operator is not relaxed about winter
Electricity is where El Niño risk extends well beyond the farm gate. Transpower’s March 2026 Energy Security Outlook reports national controlled hydro storage at 103% of historic mean, which sounds comfortable until you read the fine print. NIWA’s seasonal forecast indicates below-normal rainfall most likely for the west of the South Island, including key hydro catchments.
Transpower’s language is unusually direct, emphasising that ongoing focus on hydro storage management and sufficient backup thermal fuels is necessary to mitigate the potential for very high prices as winter 2026 approaches. Gas and coal thermal storage are near maximum levels. That is precautionary stocking, not confidence. Any business with significant energy cost exposure, from data centres to manufacturers, should be modelling spot price volatility scenarios now, not in August.
A warmer baseline makes a moderate event hit harder
Jim Salinger, Adjunct Research Fellow at Te Herenga Waka Victoria University of Wellington, wrote in March that three converging drivers, the Interdecadal Pacific Oscillation, a warming Southern Annular Mode and the El Niño signal itself, point toward the possibility of a significant event against a steadily warming planet. New Zealand’s warming rate has increased from about 0.14°C per decade to around 0.27°C per decade since 1998.
The practical implication is that a moderate 2026 El Niño carries greater real-world impact than a moderate event would have in 2000, because it plays out on a hotter baseline. Previous standout events caused severe droughts costing the economy hundreds of millions of dollars. The World Meteorological Organisation has confirmed the past decade was the warmest on record.
The to-do list nobody wants to write
Insurers are already pricing 2026-27 renewals with increased wind and flood risk in the south and west, and drought losses in the north and east. Marex agricultural analysis flags El Niño as carrying significant implications for agricultural supply chains and market pricing.
The sectors with the most immediate exposure are primary producers facing production and water access risk, electricity-intensive businesses facing spot price volatility, construction and logistics operators in exposed regions, and any firm entering insurance renewals without updated risk profiles. The information is available. The forecasts are public. The scientists have been clear for months. What is missing is the business response. A 90% probability event that could shave half a percentage point off GDP is not weather. It is a planning variable, and the window to act on it is closing.
Sources
- Formidable El Niño expected – Expert Reaction (2026-04-29)
- El Niño 2026: NZ businesses face formidable event without plans (2026-04-29)
- El Niño 2026: 90% probability reshapes NZ business risk (2026-04-29)
- What the coming El Niño climate pattern means for NZ in a warming world (2026-05-02)
- Situation and Outlook for Primary Industries data (MPI SOPI) (2025-12)
- Energy Security Outlook – Transpower (2026-03)
- Official Information Act Response – El Niño Effect on NZ Economy (Treasury) (2015-11-23)