Scientists warn of sea-level dangers

Sea levels are rising and scientists warn that action is needed to reduce risks of damage. Photo / Supplied

The sea level is rising and scientists warn that action is needed to minimise the risks of flooding, damaged beaches and infrastructure and infected drinking water.

Sixty-five per cent of New Zealanders live within 5km of the sea, including 12 of the country's 15 largest towns and cities.

And with a sea-level rise of at least one metre predicted, storm surge flooding will start to occur in those areas more frequently on king tides, the National Institute of Water and Atmospheric Research says.

Principal scientist Rob Bell said that because of their preference for coastal living, New Zealanders needed "to really consider what rising sea levels mean for us", especially for higher tides.

Dr Bell said it must be determined which coastal areas were the most vulnerable.

As well, new developments and subdivisions must start to take into account the rising sea-level.

Higher storm surges could damage beaches, seawalls, buildings, roads and other infrastructure; they might also affect drinking-water supplies in lowland rivers and groundwater, he warned.

A report by Niwa and Victoria University last year looked at how the predicted sea-level rise would affect the Mission Bay and Kohimarama area in Auckland.

It found that even with conservative predictions of how much the sea would rise, it would present a "significant risk to the people and property" of the community, especially during storms.

The New Zealand Climate Change Centre is holding a two-day conference at Te Papa in Wellington next week to discuss the "growing concern".

As well as a speech from Dr Bell, there will speakers from the British Environment Agency, Massey University and oceanographer John Church from the Centre for Australian Weather and Climate Research.

Scientists will present a synthesis of recent projections for sea level rise, discuss the uncertainties associated with these projections and will identify anticipated impacts on New Zealand's coastal environment and infrastructure resulting from climate change.

Said Dr Bell: "Planners and engineers here in New Zealand need sound guidance on what sea level rises are expected along our shores, working around the key uncertainty about how quickly the polar ice sheets may melt in future."