Beached as – the tide’s
New Zealanders love the coast so much that we’ve established countless communities hard up against it. But as the climate changes and the sea edges closer, that affection may quickly become a dangerous affliction. Charlie Mitchell reports.
When the sun is out, Tracey Reeves perches atop a seawall with her fishing rod, resting her coffee on one of the large, jagged boulders holding back the sea.
On a weekday morning, locals are walking their dogs along the concrete footpath trailing the top of the seawall. Waves on a recent high tide scattered some of the rocks, which are being replaced by contractors with a digger.
One of the great attractions of life in Moanataiari, a suburb of Thames on the Coromandel coast, is that it’s surrounded by water. For an angler like Reeves, who lived in Auckland for decades where she built boats, the appeal of a quiet life by the water was obvious.
From her fishing spot, Reeves can keep an eye on the television in her living room, which is several metres below her.
The suburb was built on reclaimed land, which is slowly sinking; some of the land is now below sea-level, meaning that at high tide, the water level can rise above the houses. From above, it has a peculiar effect: Moanataiari looks like a mixing bowl floating in a sink full of water.
For Reeves, her new life in Moanataiari was perfect until the first big storm. It arrived on the morning of January 5 this year, at the same time as a king tide.
Northerly winds fuelled waves that screamed down the Firth of Thames and smashed against the seawall, every so often flooding on to the road and leaking through the top of the seawall. At its height, waves were crashing over the wall and down on to the road.
‘‘It was the first storm we’ve experienced of that size,’’ Reeves says. ‘‘We sit here and we’re below the water when the tide comes in, and that day I think every seventh wave was higher than the wall. It was quite frightening.’’
Reeves took several videos before the storm hit its peak. In one video, she scans the top of the seawall where the rocks are scattered everywhere, including her coffee table. ‘‘It’ll never be the same,’’ she says.
Another video shows a council officer rushing to his car and driving away as a large wave crashes over the wall.
The day after the storm ended, the tide receded, and everything was quiet. Reeves was mowing the lawn, and business continued as usual.
At a time when extreme weather events are becoming more frequent as a consequence of human-induced climate change, the long-term fate of communities like Moanataiari is uncertain.
Buying into a suburb below sea-level wasn’t a concern for Reeves. She did her research, told the bank, and felt it wouldn’t be a problem in the near future. She acknowledges the sea is rising, but wants to live in her house forever, so it doesn’t matter if it loses value.
The storm, however, was a harbinger of what was to come. Although it won’t worry her, she can see the impact on future generations, as storms get worse.
‘‘I sort of worry for the kids,’’ she says. ‘‘I do believe [the water] is probably going to come in. In the next 30 years I think the high tide will become an issue.’’
The damage at Moanataiari rippled further up the firth, too.
A long, narrow road traces the coastline for dozens of kilometres, linking Thames and the various bays along Coromandel Peninsula.
Much of that road is protected by seawalls, joined together in a long chain. Near Moanataiari, in a community called Te Puru, the seawalls couldn’t stop the waves, which shredded the tarsealed road like soggy Weet-Bix.
At the other end of the firth, the coastal community of Kaiaua was devastated by flooding. Waves swept into houses in the low-lying community: ‘‘[I]t’s never been this bad,’’ a local firefighter said. At the bottom of the firth, between Kaiaua and Thames, seawater flooded the farms on the low-lying Hauraki Plains; the salt in the water razed the pasture, leaving some farmers unable to milk their cows.
Many months later, the coastal Thames road is still being fixed. The repairs to the road alone so far have cost nearly $20 million.
The insurance cost of that storm was about $35m – it was the most damaging storm of the year for just three weeks, when ex-Cyclone Fehi caused about $46m of insured damages.
2018 is on track to be the most expensive year on record for insurance losses due to extreme weather, nearing a quarter of a billion dollars and close to surpassing the previous record set in 2017.
UP AND AWAY
Moanataiari is one of many New Zealand communities confronting a growing problem: the steadily rising sea.
As the climate warms, the sea will rise, likely with increasing speed. It is not a matter of if, or when, but how fast.
Sea-level rise is certain because there’s a clear, historical link between a warmer climate and higher seas. The cause is two-fold: the ocean is warming, and water expands when it’s warm, a process called thermal expansion. The other is that land-based ice – mostly glaciers and ice-sheets – has melted dramatically, transferring water once tied up on land into the sea. In Antarctica, where much of the world’s landbased ice is found, around 2.7 trillion tonnes of ice has melted into the ocean since 1992, according to recent research.
Over the last century, the sea hasn’t risen much. Around New Zealand, the average annual rate for much of the century was about 1.5mm.
It has long been expected that the sea would start to rise faster, which is shown in the latest data – seas around New Zealand are now rising 3mm to 4mm a year.
‘‘The trend has accelerated,’’ says Dr Rob Bell, a coastal oceanographer at Niwa, which supplies sea-level rise data to the government. ‘‘We’ve doubled the rate in the last 25 years.’’
There are nuances. Weather patterns such as El Nino and La Nina can counteract sea-level rise; parts of New Zealand are subsiding, meaning effective sealevel rise can be higher than average, and other areas are being lifted, partly negating sealevel rise. But there is a clear, long-term trend: the seas are rising, and doing so more quickly than they once did.
The main thing to worry