Pacific Islands on the Front Line: Falling Seas in the West, Drought Across the Region

For most regions, El Niño is a story about rain. For the Pacific islands it is that and something stranger: the ocean itself moves. In a strong event the sea surface tilts eastward across the basin — falling by tens of centimetres around the western islands even as it rises along the Americas. Combined with a wholesale shift in where rain falls, this makes the region's smallest countries some of the event's most exposed, and their governments are moving earliest.

The mechanism: a shifted rain band and a tilted ocean

Two displacements drive everything. First, the South Pacific Convergence Zone — the rain band that waters Fiji, the Solomons, Vanuatu and their neighbours — migrates northeast during El Niño, following the warm water. Islands left behind its usual position fall into drought; islands near its new position, and those in the normally dry equatorial band like Kiribati, can turn unusually wet. Second, the weakened trade winds release the warm water they normally pile against the western Pacific: NASA analyses show sea level dropping by around 20 cm in the west while rising by up to 25 cm in the east during strong events.

The falling sea matters as much as the missing rain. Atoll communities live on thin freshwater lenses floating atop seawater within the island rock; drought stops their recharge while altered sea levels and wave dynamics push salt in. And when the sea drops, reef flats that normally stay submerged are exposed at low tide. The calibration from past events is grim: Guam recorded a 53% decline in staghorn coral in the 2014-15 event, and Indonesia's Bunaken reefs suffered up to 85% coral mortality in 2015-16 exposure events, with the 1982-83 event dropping Java Sea levels by 10-15 cm. Both displacements are part of the basin-wide rearrangement covered in the science of teleconnections.

What past events did to people

Papua New Guinea carries the region's harshest memory. In 2015-16, drought combined with highland frosts — clear, dry El Niño nights let temperatures plunge at altitude — to destroy sweet potato gardens, the staple food of the densely populated highlands. Oxfam documented food insecurity reaching millions of Papua New Guineans. Frost and drought together form a uniquely PNG double blow: the same dry air mass that parches the lowlands freezes the highlands.

What officials are saying in 2026

The strongest official signal comes from Port Moresby: Prime Minister James Marape has directed nationwide preparedness as El Niño threatens a prolonged dry season, per the Prime Minister's office — an explicit, whole-of-government directive of the kind regional advocates urged after 2015-16, when RNZ reporting carried warnings that PNG needed to prepare early for a potential food-security crisis.

Across the region, RNZ reporting on regional briefings indicates 20 Pacific small island developing states face a likelihood of below-normal rainfall during this event. Fiji has issued a drought warning, with at least 30,000 people affected and water trucking operations reaching 67,000, per that reporting. In the Solomon Islands, reporting describes calls for water rationing and closures of schools and clinics as supplies tighten. These are the leading edge: with the Pacific forecast to peak between November 2026 and January 2027, the deepest water stress for many island groups lies in the months around and after the peak, into 2027.

What to watch next

Watch four things. First, rainfall outlooks island group by island group — the SPCZ's exact displacement decides who dries and who floods, and national meteorological services' drought declarations will map it in real time. Second, PNG's highlands as the austral winter of 2027 approaches: frost reports from the sweet potato belt were the human tipping point of 2015-16. Third, water logistics — trucking volumes in Fiji, rationing decisions in the Solomons, desalination and shipping to atoll nations — which measure the gap between preparedness directives and delivery. Fourth, the reefs: western Pacific tide-gauge readings through the peak will indicate how much reef-flat exposure this event forces, an ecological loss that compounds the fisheries pressure island economies already face.

The region's governments have moved earlier than in 2015 — the question the next twelve months will answer is whether early directives translate into water, food and shipping where they are needed. Follow each national declaration and response as we log it in our news section.