Magazine article New Internationalist

Global Warning: Sea Levels Are Rising in the South Pacific and Set to Rise Higher

Magazine article New Internationalist

Global Warning: Sea Levels Are Rising in the South Pacific and Set to Rise Higher

Article excerpt

Global Warning

Sealevels are rising in the South Pacific and set to rise higher. Patrick Nunn explains why the islands are so Vulnerable.

THE PACIFIC most tourists see is the stuff of fantasy. Behind the veneer, however, lie environments under considerable stress. The worst symptoms of this stress have been caused by resource mismanagement and the never - ending search for export dollars. But another problem looms large over Pacific island nations as they struggle to sustain themselves into the twenty - first century - and that is global warming.

The evidence that our planet's surface has been warming for the past 100 years or so is overwhelming. Yet the data on which this evidence is based comes largely from industrialized countries - not from small Pacific islands with only minuscule industrial sectors. Long - term, regularly monitored climate stations are few in the Pacific and data quality is often suspect. So there has been some doubt about whether global warming has indeed affected this vast region.

Yet the three best sites - in Fiji, Hawai'i and Aotearoa/New Zealand - all show an unequivocal result. The Fiji data from Government House in Suva, for example, show a net rise of around 0.5degreeC from 1884 until 1986, when the recording station was relocated. There seems little reason to doubt that the Pacific has been warming at approximately at the same rate as almost everywhere else. Throughout history climate has been changing. So too has the surface of the oceans. The connection is twofold. Just as water expands slightly when heated, so does the upper part of the ocean when its temperature rises. Ice will melt when heated - but, if it is floating, the sea level will not change. This will happen only if the ice is on land. When temperatures rise, through both thermal expansion of ocean water and land - ice melt, the sea - level will rise.

The sealevel in the Pacific is undoubtedly rising and has been for at least 100 years - probably twice as long. The few long - term tide - gauge records that we have suggest that it has been rising at a rate of around 1.5 millimetres per year. This may not sound very threatening. But on a gently sloping coastline a rise of around 15 centimetres, similar to that of the past 100 years, can cause flooding of tens of metres of shoreline.

This is a depressingly common story throughout the Pacific islands. On several occasions over the past ten years I have organized my students - who come from 12 different Pacific island nations - to conduct interviews with elderly, long - term residents of long - established coastal settlements in their home countries. These people were asked how their coastlines had changed during their lifetimes. With a few exceptions the results demonstrate widespread inundation, over the past 60 - 70 years at least, throughout the south and west Pacific.

Admittedly the hard evidence is not as good as that for temperature. Sceptics have tended to latch onto tide - guage records. Because they are too short - less than 30 years - and/or because the place where the tide gauge is located is itself moving, they do not show a clear pattern of sealevel rise.

Sitting in their offices, some government planners are keen to deny the reality because to admit it means recognizing a problem which demands more dollars than they can afford. Yet, back in their home village drinking kava with their relatives, they hear about the receding shoreline and look worriedly at the foundations of their grandparents' house, poking out of the water 100 metres from shore.

Daunting prospects

Projections by the sophisticated computer models of the Inter governmental Panel on Climate Change (IPCC) - the group of some 700 experts given this task in 1987 by the UN - suggest that the rates of temperature and sealevel rise will increase three - to five - fold in the next 100 years or so. The effects of the past century will be dwarfed by those of the next. …

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