Issued: 16 October 2026
LOW SEA LEVELS LINKED TO El Niño MAY INCREASE ENVIRONMENTAL RISKS AROUND SOLOMON ISLANDS.
The Solomon Islands Meteorological Service is monitoring unusually low sea levels across parts of the northern and western Solomon Islands, a pattern consistent with the historical El Niño events. Current Observations from the Tarekukure Wharf tide gauge show water levels approximately 0.30 metres (30cm) below predicted tide levels, while satellite observations indicate significantly below-average sea levels across Santa Isabel and the New Georgia and Marovo regions.
El Niño occurs when the trade winds that normally push warm surface waters towards the western Pacific weaken. As a result, ocean waters and sea levels shift eastward towards the central and eastern Pacific Ocean, leaving the western Pacific, including parts of Solomon Islands, experiencing sea levels below normal by around 10 to 40 (30?) centimetres, and in some cases more during stronger events.
With El Niño now well established and expected to strengthen further towards the end of this year, these lower-than-normal sea levels are likely to persist over the coming months. For enclosed reef and lagoon systems such as Marovo Lagoon, reduced sea levels mean less water passing over reef barriers during tidal cycles. This can slow the exchange of water between the lagoon and the open ocean, reducing natural flushing and circulation.
At the same time, satellite observations show elevated chlorophyll concentrations along parts of the coastline, indicating an increase in microscopic marine plants known as phytoplankton. While phytoplankton are a natural and important part of marine ecosystems, unusually high concentrations can signal nutrient-rich conditions that may lead to algal blooms. When large amounts of organic material break down, the decomposition process can consume oxygen in the water, placing stress on marine life.
Sea surface temperatures in the area are currently near normal or slightly cooler than average. This suggests that the observed environmental changes such as in Marovo lagoon are not being driven by a marine heatwave. Instead, the combination of lower sea levels, reduced water exchange, and reduced naturally occurring nutrient inputs in combination with other natural processes may be the cause.
These factors may contribute to periods of reduced dissolved oxygen, particularly in sheltered or poorly flushed areas. Fish and other marine organisms can become stressed when oxygen levels fall too low, and in severe cases, localised fish mortality events may occur, such as the incident in Marovo
The Solomon Islands Meteorological Service advises that, with El Niño forecast to continue strengthening into early 2027, communities and resource managers should remain alert to the potential for ongoing impacts in enclosed lagoon systems across the country. Continued monitoring of sea levels, water quality, and marine ecosystems will be important to better understand and respond to these changing conditions.
ENDS//