Huge costs loom as sea levels creep up

Press, 26 September 1988, Page 5

Huge costs loom as sea levels creep up

PA Wellington New Zealand faces horrendous costs in saving coastal communities as the greenhouse effect raises sea levels, says the Conservation Department’s climatic change specialist, Dr Jeremy Gibb. As the climate warms, the oceans are expected to expand, raising sea levels at least half a metre within 50 years and by up to 1.5 m within a century. Dr Gibb expects widespread retreat of the 11,000 km of coastline by about the year 2065. He urged local bodies to begin arranging an orderly withdrawal of assets from the coastal zones. Preliminary studies by local authorities suggest that low-lying urban areas, such as Auckland’s downtown area, and Dunedin’s St Kilda Borough, will flood if they are not protected, as will many West Coast settlejnents. The Northland Regional

Council’s water and soil planning officer, Ms Susan Clayton, said the rising sea level was the most serious planning issue facing Northland. A predicted half-metre rise in sea level was conservative. But even with a 20cm rise, some beachfront hotel developments in Northland would find their basements flooded. Dr Graeme Campbell, who has been studying the possible effects of a sea level rise for the Auckland Regional Authority, said part of the problem for downtown Auckland was that so much of the area was reclaimed. “Queen Street itself is built on a tidal canal, and there’s an underground river that runs under the street. “On the Manukau Harbour, there is the sew-age-purification works; we would have to build them higher; and I am not sure what you would do about Auckland Airport. Low-ly-ing places like Mission Bay will be thretened as well.”

The Hauraki Catchment Board’s general manager, Mr Richard MacLaren, said a 1.5 m rise in sea level would mean the loss of a substantial amount of farming land on the Hauraki Plains. In Wellington, the Hutt Valley already has problems with flooding. If sea levels rose, Petone could be under threat, said the manager of the Wellington Regional Council’s land information department, Mr Gary Fitzwilliam. The downtown area of Wellington would have considerable problems with drainage and with flooded basements, and as with other ports round New Zealand, wharf areas might" have to be raised. Dr Gibb said that by 2100, Hokitika would be a shallow lake. “Low-lying cities like Christchurch will suffer increased flooding and Pauanui Beach in Coromandel will retreat from erosion,” he said.