According to the recent report by Commissioner for the Environment Dr Jan Wright ‘Preparing New Zealand for rising seas: Certainty and Uncertainty' it is not a matter of if but when New Zealanders will be detrimentally affected by sea-level rise caused by climate change.

Apparently 9000 Kiwi homes are vulnerable. The report notes that in Tauranga, there are many pockets of low-lying land around the harbour. Most of the 1291 low-lying homes are in Mount Maunganui and the suburbs of Otumoetai and Matua. Most of the 107 low-lying businesses are near the airport.

Thirty-five roads could also be flooded.

An article in the Spring 2015 issue of the University of Auckland Alumni magazine ‘Ingenio' (page 24) is therefore salient. A joint research project involving three universities (two in NZ and one in the UK), using leading edge simulations, focussed on how estuarine environments with and without mangroves responded to sea-level rise.

It revealed that mangrove forests play a central role in such environments, and could exercise a crucial role in protecting coastal areas in the days to come. The ability of mangroves to create a buffer between sea and land occurs even when an area is subjected to potential rises of up to 0.5mm per year.

In 2010 Debra Stokes examined the physical and ecological impacts of mangrove expansion and removal in Tauranga Harbour for her doctoral thesis. She notes that where seaward sections of the mangrove population have been cleared at Waikaraka, it has resulted in a lowering of the intertidal surface at a mean rate of 17 mm yr-1, which I believe increases the height of tidal inundations at these locations. She adds: 'These findings have implications for the sustainability of the remaining mangrove and salt marsh should sea-level rise continue."

In light of all this, I would like to suggest that the case for the removal of mangroves from various sectors of Tauranga Harbour is becoming less clear-cut (excuse the pun). There is evidence that protecting buffer zones between land and sea may well serve our best interests in the decades to come, which is a factor the mangrove managers may need to mull over carefully.

One of Dr Wright's key findings is that the Government must do more to help councils and communities deal with sea level rise. Seven of her eight recommendations focus on improving the direction and advice given to councils, who ‘must use science that is fit for purpose, and engage with communities in a measured way and with empathy'. I hope that our local bodies continually review their approaches as further evidence becomes available.

Phillip Donnell, Welcome Bay.