Sea levels: $19b bill for buildings

Replacing the buildings around New Zealand waiting to be lost to rising seas could exceed $19 billion, reports say.

Surf life saving clubs are already considering their options, but if the sea level rises by 1.5 metres, as expected by 2100, more than 6000 kilometres of drinking water, wastewater and stormwater pipes and 2000 kilometres of roads are also at risk, the recently released Our Marine Environment report says.

Climate change author Neville Peat, who published Invading Seas last year, said it was time to act.

‘‘Councils need to be looking in more detail than what they have been up until now.’’

Sea level rise wouldn’t just affect the buildings immediately beside the sea, like surf lifesaving clubs, but would also raise groundwater levels and affect infrastructure more inland.

‘‘The risks are pretty scary when you look at Napier, Christchurch and Dunedin, you can see some pretty scary numbers in terms of residences and treatment plants, substations at risk ... the numbers get up in to the thousands.’’

The expected increase in king tides would only increase that Climate change author Neville Peat

risk, he said.

Surf Life Saving New Zealand national life saving manager Allan Mundy said the plight of the surf life saving buildings could be eased by better dune management.

‘‘What we can do to save the clubs, and the beaches, is to encourage good dune communities,’’ he said.

Sea walls were very expensive to maintain, but the protection of a dune could be almost free, he said.

But he warned it wouldn’t be a quick fix.

‘‘Looking at our beaches, a majority of them will benefit from this kind of project.’’

The $19b price tag could be even higher if sea levels exceeded the projections, the Ministry for the Environment’s Our Marine Environment report said, and it warned recreation and heritage could also be affected.

A recent Department of Conservation (DOC) report estimated that 331 DOC assets and 119 visitor sites were potentially at risk from coastal inundation.

Similarly, 6 per cent of New Zealand’s Archaeological Association archaeological sites are considered to be at risk.

Many coastal iwi and hapu¯ have marae and other sites (like urupa¯) in vulnerable areas, which are important to their identity and the wellbeing of their people.

Research released in August by Niwa and the Deep South Science Challenge estimated that for every 10 centimetres of sea-level rise, buildings worth $2.5b would become exposed to potential flooding.

The risks are pretty scary when you look at Napier, Christchurch and Dunedin.