El Nino's Impact on Oceania

▪ 1999

by Barrie MacDonald

      During 1997-98 the El Niño weather pattern wreaked more havoc and destruction on the Pacific Islands than it had since 1982-83. The adverse effects included severe drought in the western Pacific, an increased frequency of cyclonic storms in the eastern Pacific, and consequent impacts on subsistence agriculture, export production, public health, and housing.

      El Niño ("The Child," in reference to the Christ Child) was the name given by South American fishermen to the warm current that sweeps the Pacific coast every few years, arriving at about Christmas and replacing the usually cold Humboldt current from the south for months at a time. Now recognized as part of a broader phenomenon (the El Niño Southern Oscillation), this variant on the usual weather pattern results in increased rainfall and more frequent cyclonic storms in the eastern Pacific. For the western Pacific, El Niño causes long periods of reduced rainfall—with resultant drought conditions in the worst-affected areas—and cooler ocean temperatures that reduce the risk but not the occurrence of cyclonic storms.(See Oceanography. (Earth Sciences )) The warmer sea temperatures (by 3°-4° C [5.4°-7.2° F]) increase sea levels by as much as 0.5 m (1.6 ft), which can threaten coastal settlements in much the same way as global warming is projected to do during the next century. There is already concern that the more frequent occurrence of El Niño since 1977 represents a trend for the future.

      La Niña ("The Girl Child") brings contrasting conditions, with cooler ocean temperatures, less rain, and less frequent cyclones in the east and an increased risk of cyclones in Fiji and the islands to the west. As early as July 1997, the Southern Oscillation Index suggested that a severe El Niño pattern could be expected. By December 1997 ocean temperatures were at their highest this century. Towards the end of 1998 the Index indicated that, rather than a return to "normality," a major La Niña could be expected, bringing drier conditions to French Polynesia, the Cook Islands, and Tokelau; an increased incidence of cyclonic storms in Fiji, Vanuatu, New Caledonia, and Solomon Islands; and an easing of drought conditions on the eastern coasts of Australia and New Zealand.

      The 1997-98 El Niño followed a classic pattern. Early in 1997 warmer ocean temperatures were in evidence on the Pacific coast of South America; by midyear, reduced rainfall (sometimes as little as 10% of the usual precipitation) in the western Pacific had given way to serious drought conditions in Papua New Guinea, Solomon Islands, the Federated States of Micronesia, and the Marshall Islands. Similar conditions were experienced in eastern Australia and New Zealand. The season for strong cyclonic storms, usually defined as November to March, was particularly severe in the eastern Pacific in 1997-98, with French Polynesia experiencing four major cyclones during that period. In the adjacent Cook Islands, Cyclone Martin was the most severe in living memory. Although El Niño generally results in a reduced risk of severe storm activity in the western Pacific, Solomon Islands and Vanuatu were both struck by cyclones in January 1998.

      In Papua New Guinea some 750,000 people were affected by drought through 1997 and early 1998, resulting in crop failure and consequent malnutrition, with claims of up to 70 deaths attributable to starvation. Mining operations at Ok Tedi and Porgera were suspended because of the lack of water. With Australian assistance, relief measures, including the distribution of food, were implemented. In the smaller islands and atolls of Micronesia, drought conditions were particularly severe, continuing beyond mid-1998 and leading to the declaration of disaster-area status in the Federated States of Micronesia and the Marshall Islands. Measures taken to alleviate drought conditions included the importation of desalination plants and of equipment that treated groundwater to make it drinkable and also the shipment of water by barges to the worst-affected islands.

      Further effects of El Niño included 50% reductions of sugar exports from Fiji, coffee exports from Papua New Guinea, and squash exports from Tonga. Fisheries were also affected. The warmer water temperatures on the South American coast caused a sharp reduction in the anchovy harvest. Tuna, a highly migratory species, usually congregate for some months of the year to the north of New Guinea; under El Niño conditions, stocks were more dispersed, and Solomon Islands had a catch that was one-third larger than usual. With some 70% of the world's tuna fishery in the Pacific Ocean, the implications of such shifts for nations that depended on the exploitation of an exclusive economic zone were obvious.

      Aside from their direct costs, both droughts and storms adversely affected subsistence and cash crops for a significant number of Pacific Islanders, further depressing economic activity in much of the region. The drought also increased the incidence of bush fires in countries ranging from Papua New Guinea to Samoa, damaging health as well as forests. Compromised water supplies resulted in an increase of gastrointestinal diseases and to increased vulnerability to cholera in some areas.

      At a time when many of the smaller Pacific Islands countries faced global warming with some trepidation, perceiving rising sea levels as endangering their existence, the increasing frequency of El Niño posed a threat that was at least as damaging in its potential effects and was more immediate in its impact. The climatic extremes generated by this system and its cold-water-current opposite, La Niña, carry severe risks for those very small countries, with their fragile ecosystems, weak infrastructures, and narrow resource bases. Most were already heavily dependent on foreign aid for capital development and, in some cases, for recurrent expenditures. It seems certain that their economic struggles will only be accentuated by the continuing climatic challenge.

Barrie Macdonald is a professor of history at Massey University, Palmerston, N.Z.

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