Journal article

The relative (un)certainty of subnational population decline

15 Jun 2017

“Prediction is very difficult, especially about the future.” This quote is attributed to Danish physicist and Nobel prize winner Niels Bohr, but the difficulty of making predictions does not stop us from making forecasts of economic, demographic, and other variables. Investors, businesses, policy makers and others use these forecasts to inform their decisions about investments and policy settings where understanding of the future trajectory and levels of costs and benefits are essential. One key example is forecasts of future population. The size and distribution (whether geographic, age, ethnic, or some other distribution) of the future population is a critical input into urban and other planning. Understanding the methods and limitations of forecasts is an important but often underappreciated task for planners and policymakers.

In this article, I draw on more than a decade of experience in developing population projections for local councils and others, as well as the latest in population projection methods, to provide an answer to the question: “Is population decline inevitable for New Zealand’s rural and peripheral areas?” A recent term, coined by economist Shamubeel Eaqub (2014), ‘zombie towns’, refers to population centres facing irreversible population decline. However, such a categorical statement (‘irreversible population decline’), does not reflect the uncertainty of population projections, or indeed the uncertainty of the future population distribution of New Zealand. Moreover, as I show in this article, it does not reflect the projected experience of the majority of territorial authorities (TAs) (or indeed, towns) in New Zealand, even many in rural or peripheral areas. While many areas are currently in decline, and these and others will decline in the future, such population decline is not certain except in a minority of cases that is large and growing.

In this article, I first outline some of the key points that decision-makers need to understand about population projections, focusing especially on the role and sources of uncertainty. I then briefly outline a recently developed state-of- the-art stochastic subnational population projection model (Cameron & Poot 2014a, 2016). Finally, I use the model to evaluate the probability of New Zealand’s TAs experiencing population decline over the periods 2013–2023, 2033–2043 and 2053–2063. This exercise complements the analysis at the town level by Jackson and Brabyn (infra), and clearly charts the progression from subnational population growth to decline, particularly for rural and peripheral areas.  


This article posed the question: “Is population decline inevitable for New Zealand’s rural and peripheral areas?” The answer is clearly ‘no’. I have demonstrated that fewer than one-third of TAs are projected to experience near certain decline, which may be a high or a low proportion, depending on one’s perspective. However, demography is clearly not destiny. In a few TAs, the probability of population decline reduces over time. Those TAs tend to have relatively youthful populations and relatively high fertility rates, neither of which are necessarily replicable for policymakers in other areas.

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