Study sounds alarm on New Zealand's sinking coastline, rising sea levels

Scientific projections show sea levels in New Zealand are rising twice as fast as previously thought in many parts of the country.

The research found that parts of Wellington, the capital, will see 30 centimetres of sea level rise in just 18 years’ time. This would cause typically once-in-a-century floods every year. AFP - DAVID ROWLAND

Released Monday, the data reveals that homes and other infrastructure in Auckland, Wellington and elsewhere risk being inundated decades earlier than expected.

NZ SeaRise is a five-year government-funded research programme that combines data on sinking land with up-to-date international sea-level rise projections.

Involving some 30 local and international experts, it takes into account the natural rises and falls of the country’s coastline, as well as climate change and warming temperatures.

Global sea-level rise of 25-30 cm by 2060 is unavoidable regardless of our future emissions pathway. But in many of NZ’s most populated regions vertical land movements mean these changes may happen 20 to 30 years sooner than previously expected https://t.co/AC9EsguIJ3 pic.twitter.com/IX2ovlb7lc

— NZSeaRise (@NZSeaRise) May 2, 2022

Less time to act

Alarmingly, the research found that parts of Wellington, the capital, will see 30 centimetres of sea level rise in just 18 years’ time. This would cause typically once-in-a-century floods every year.

Authorities in New Zealand had not expected levels to reach this threshold until 2060.

More broadly, existing global emissions policies show sea levels are expected to rise about 0.6 meters by the year 2100. 

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However for large parts of New Zealand this would double to about 1.2 meters, says co-leader of the NZ SeaRise program, Tim Naish, of the Victoria University of Wellington.

"We have less time to act than we thought,” he said of the “unavoidable rise” in sea levels.

Some areas in Auckland and Wellington are sinking 3-4 millimetres a year, which corresponds with the annual rate at which the sea is rising.

It is expected the new information - which halves the time authorities have to mitigate against climate change - will have strong consequences for adaptation planning and policy measures.