25 Feb 2023

Prof Jonathan Boston: how to manage managed retreat

From Saturday Morning, 8:15 am on 25 February 2023

Recent extreme flooding events have bought the need for managed retreat into sharp focus.

We will have no choice but to move tens of thousands of people out of harm’s way over the coming decades according to New Zealand researcher Jonathan Boston. 

Emeritus Professor of Public Policy at Te Herenga Waka Victoria University, Boston is a contributor to a recently released working paper focussed on developing recommendations for the government's proposed Climate Adaptation Act.

Erosion at Waihi Surf Life Saving Club.

Cyclone Hale caused widespread erosion to North Island beaches, including at Waihi Surf Life Saving Club. Photo: Supplied / Waihi Surf Life Saving

We're seeing climate change playing out in real time, he tells Kim Hill, and cross-party consensus is needed to respond in a rational way.

Who decides when to retreat and on what basis, what should be the planning process and how should retreat be funded are among the thorny problems to resolve, he says.

“We urgently need an informed national conversation on these big issues.

“We can't put it off any longer, we've put it off for years, to be honest, we can't put it off any longer.”

A cross-party consensus is needed to ensure any policy solutions are long-lasting, he says.

“We need a platform that will endure across generations, as we've had with EQC and ACC.”

A Ministry for the Environment estimate is 750,000 New Zealanders and 500,000 buildings worth more than $145 billion are in harm's way but there is huge uncertainty surrounding the extent of the risk, he says.

“We don't know exactly how much sea level rise we're going to have this century, let alone in the coming centuries.

“That will depend on what happens globally in terms of greenhouse gas emissions, whether we meet the Paris targets or anything close to the targets, and it doesn't look very promising at the moment.

“It also will depend exactly how the climate system actually impacts on different parts of the planet.”

What we do know for certain is sea level rise will have profound impacts across the world, he says.

“The seas will rise, and they will rise at an ever-increasing rate this century and that will have huge damage globally, including to some of the largest cities on the planet and some of our largest cities like Dunedin, Christchurch, Wellington.”

New Zealand has another contributory problem, he says.

“About 40 percent of New Zealand’s coastline is subsiding, at least two millimetres a year, which is two centimetres a decade, and some of the coastline is subsiding at a much faster rate, like five to six millimetres a year or five to six centimetres a decade.

“Now, that might not sound very much. But when you put the subsidence together with the sea level rise, then you're talking very significant numbers over time.”

Moving towns, cities and New Zealanders in their thousands will require collective responsibility and social solidarity.

“For a very long time, we have shared the costs of earthquakes, the cost of war and so on.

“And that is a really critical principle, in my view, in terms of sea level rise, and indeed climate change more generally, because the impacts that people are going to suffer, are going to be often arbitrary, certainly unwanted and often uninsurable.”

And the people to suffer most will have contributed least to the problem, he says.

“The question here is to what extent do we share the costs of climate change impacts, including more powerful storms and sea level rise? To what extent do we share those costs collectively? Or put a significant proportion of the burden on the individuals who will be affected?”

Intergenerational fairness should guide any policy decisions, he says.

“We should perhaps try and pre-fund some of the costs, in the same way that we're pre-funding, the costs of retirement incomes through the Cullen fund, and in the way that we pre-fund to some extent the costs of earthquakes through the natural disasters fund of EQC.”

Poorly designed policy could exacerbate future problems, he says. Inadequate compensation for people asked to move for example.

“First of all, we won't really have a social license for managed retreat, certainly voluntary managed retreat, and the second is, people will understandably demand protection, rather than retreating.

"And the risk is we will end up building all sorts of defensive structures, which are not going to be cost effective.”

NZ Defence Force/supplied
[57] An aerial view of the eastern end of Westport during the July 2021 flood.

Photo: Supplied / Defence Force

This could increase long term risk, he says.

“For example, we could put a bund around Westport - that is under serious consideration at the moment - that will protect Westport for a period of time from the onset of more powerful storms and sea level rise, but it won't protect Westport forever.”

The question remains whether that is an effective use of resources, he says.

"The good citizens of Westport may not like to hear what I'm going to say. But in my view, we need a serious conversation as to whether or not towns like Westport should be protected, or whether we should buy them out and build a better Westport in a safer location.

“That kind of conversation has to be had, if it isn’t had soon, it will have to be had in the future.”

Such conversations are needed nationwide, he says. Central government, and by extension tax payers, will inevitably bear most of the cost.

“Moving towns like Westport, moving whole suburbs like South Dunedin or South Shore in Christchurch, or Petone in Wellington, significant parts of Whakatāne or Whanganui or Whangārei and so on they will almost certainly require central government involvement, because the central government will be paying for at least some of the costs.

"In my view, it's going to probably bear the burden of paying for property buyouts in the main because I just don't see local government having resources to do that.”

Planning regulations, fairness, good public housing in safe areas and avoiding costly and ineffective defensive measures, will need the buy-in of politicians across the spectrum, he says.

“Because it is ultimately they who will be deciding what kind of policies are put in place, and I don't envy them, but we need to do our best to create a context in which they can make prudent decisions for the future.”