The Mahurangi Magazine

Select Page

High time to ramp up response

by 1 Sep 2009Sea-level rise0 comments


Ban Ki-Moon (en route to Antarctica): ‘social cohesion is essential to addressing the threat of climate change. When societies rally together in recognition that this is a challenge that no sector can take on alone—that is when we see real progress.’ photograph United Nations

Blame it on that unabashed alarmist, Noah. For establishing the notion that humanity could be wilfully drowned and a fresh start would only be few months in an ark away.

The sad fact is that not all the animals can be saved. Sure, the likes of the lions and the tigers and the kangaroos will be saved, albeit in diminished areas. But global warming will arbitrarily extinguish a million species—their ability to adapt to new or altered habitats will be outstripped by the pace of climate change.

As impoverishing a spectre as that is, it is the wholesale dislocation of human populations that has the potential to make life desperate for more than half a billion, and dangerous for the balance.

Urgent global preparation is needed, far beyond the hopelessly non-strategic goals of capping and trading carbon dioxide et al—population is the gorilla in the cupboard.

Sir David Attenborough heads up the Optimum Population Trust that is working to keep Britain’s growth below current projections—the equivalent of another couple of Londons by 2050—to relieve pressure on the environment. It has been demonstrated that population can be controlled on a global scale—to the tune of 400 million fewer souls than otherwise currently inhabit China.

While reining in population may be the single most urgent need, Aotearoa has far more strategic duties regarding sea level rise. The most cost-effective means of reducing the damage to coastlines is to increase the resilience of coastal vegetation. The frontline of this work is establishment of sand-binding plants and pōhutukawa.

Even a dense cover of spinifex and pīngao will not withstand severe storm events, particularly when added to higher high tides. But it will allow dunes to recover more quickly between storms. This will be crucial in ensuring that low-lying areas inland remain productive longer and in turn can be made more resilient with the planting of indigenous species.

While this applies mostly to beaches outside the harbour, Sullivans, Mita, Ōpahi and Scotts Landing all need sand-binding plant programmes.

But the particularly Mahurangi issue is its hundreds of kilometres of readily erodible soft-rock and clay bank coastline.

These coastlines, in the main, and in the long term, cannot be armoured, although some will be as a short-term measure. Again, the only cost-effective response is to increase the coastline’s resilience, and again, with indigenous species. The standout species, of course, is pōhutukawa.

As soon as is practicable, some millions of pōhutukawa and other plants are called for. Many of these will prove to be sacrificial, as storm events bring down banks and cliffs. But many will mature to seriously buttress and shade the shoreline—shade plays an important role in reducing the wetting and drying that is the main cause of foreshore erosion.

In or out of the Auckland region, the Mahurangi catchment will be hard-pressed to find the many millions of dollars needed. Multiply this by the coastline of Aotearoa and it is starkly apparent why producing and establishing coastal plants smarter must be strategic goal, right up there with methane reduction—as Professor Sir Peter Gluckman puts it, science-informed, strategic and collaborative.

Mahurangi is already at the forefront of this work, with the open-ground trials, which demonstrate that large-scale forestry-style nursery methods work for indigenous species. The forestry and dune plant scientist behind these trials, forester of the year Dr David Bergin, was scheduled to speak to the Mahurangi forum on Monday evening. However, sudden changes to his schedule, David works for Scion in Rotorua, has necessitated in a rain check—Auckland Regional Council’s sediment management specialist, Jack Turner, will talk on forestry and sediment.

Human civilisation, in the 14 000 years (give or take) since the Neolithic Revolution, has inadvertently achieved the previously unimaginable: Warming the planet, raising its oceans, and changing its very axis—which in itself, ironically, doesn’t appear to matter!

For the love of Mahurangi, humanity and the natural world, it’s time to ramp up a strategic response.

Receive Mahurangi Magazine updates

Join the mailing list to be notified of new pages.

Thank you for subscribing to Mahurangi Magazine!