The disquiet Earth

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    Even though I live nearby, it took me a while to notice what was missing. 

    In summer, a path curled between the Te Huruhi urupā and the sea, as it has done ever since the urupā fence was built. 

    Now, big chunks are missing, eaten by the year’s storm surges. At one point there is barely a finger length of crumbling soil left between the path edge and an urupā fence post.

    As damage goes, this doesn’t seem like much, especially when compared to the ravages of Cyclone Gabrielle in Northland, Auckland, Coromandel and down the East Coast of the North Island. The storm which killed eleven people and wrecked homes, farms, marae, breweries, vineyards, orchards and roads wracked up costs in the Hastings District alone of over $2 billion.

    But the loss of this small path on Blackpool Beach is disquieting; not only flagging a serious threat to a burial site of emotional and historic significance, but also as a reminder of what lies in store for coastal communities.

    Gabrielle’s central low pressure, senior New Zealand climate scientist James Renwick points out, was lower even than the behemoths Cyclone Bola in 1988, and Giselle (the same storm that sunk the Wahine ) in 1968, making it unusually intense. This was, he says, likely the result of a warmer atmosphere and sea surface.

    Climate change may not cause cyclones, but it makes them worse. Along with storms of increasing ferocity, the Te Huruhi urupā faces rising tides; the seas have already risen 20 centimeters in the past 100 years, and this rate is quickening. We know the sea is rising; by how much depends on the amount of greenhouse gases we continue to pump into the atmosphere.

    “We can’t avoid [at least] 30 centimetres of sea-level rise by mid-century,” paleoclimatologist Tim Naish told Newsroom last year. “That’s baked in, that’s unavoidable, so we can plan for that.” 

    In a book published last week, Under the Weather – a Future Forecast for New Zealand, Renwick explains how tiny differences in sea level rise can have big effects on a typical beach – one with a slope between 1-in-20 and 1-in 100. 

    “A 25-centimetre rise in average sea levels would shift the high-tide mark 20 to 100 times further inland – somewhere between five and 25 metres. We are virtually guaranteed 50 centimetres of sea-level rise this century, meaning that the high-tide mark is likely to shift inland between 10 and 50 metres. That means anything located within a few tens of metres of the current high tide mark is going to be in trouble.”

    In climate science, small variations have big effects. And big storms amplify sea level rise.

    “When a storm affects the coast, three things happen,” Renwick says. “First, the low pressure near the centre of the storm lifts the level of the sea surface up, typically about 20 centimetres in an average storm. The lower the air pressure and the stronger the storm, the more the sea level is raised. Second, if onshore winds are blowing, they will pile up seawater at the coast, raising the sea level even more. Finally, wind-driven waves coming into the beach will raise the sea level again. With just 10 or 20 centimetres of sea level rise, a sea wall which was once high enough to keep the waves at bay will find itself over-topped.” 

    If we cannot contain greenhouse gas emissions, the Greenland and Antarctic ice sheets will pass their melting ‘tipping point’ and billions of people around the world, their homes, roads, airports, hospitals, schools and ports will be inundated. The earth has been here before – fifty million years ago crocodiles basked at the North Pole and sea levels were 70 metres higher than they are now. 

    New Zealand, says Renwick, is temperate enough to escape the worst consequences of climate change, at least for a while. But being such premium real estate in this new world will come with its own challenges, as will accommodating climate refugees from stricken neighbouring nations, including Australia. 

    Aotearoa, as of 2019, has a law that says we must get to net-zero carbon dioxide emissions by 2050. How do we do it? Renwick’s wish list: boosts to renewably powered public transport; incentives for ‘active transport’ (walking and cycling); affordable car-sharing schemes; incentives for buying electric vehicles and a national charging-station network; big investments in solar and wind power; better home insulation; more efficient home appliances; no more coal boilers; climate-conscious development (increased urban density, no urban sprawl); climate-conscious land-use (for instance: not using dry country for dairy farming); growing more plant-based food.

    These aren’t ‘nice-to-haves’. The urupā’s crumbling path is speaking to us, although the earth’s megaphone is already deafening.

    As Catherine Delahunty recently tweeted: “Canada burning, New York choking, Arctic melting, Pacific Islands drowning and Aotearoa counting costs of cyclones, but still the denial on my Twitter feed…” • Jenny Nicholls

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