Possible Future Population Growth Scenarios for Christchurch and Canterbury
What will happen in the future? Will Christchurch’s and Canterbury’s population stabalise into a steady-state form or will it continue to evolve and change?
A review of historical changes and a discussion of some factors which will affect the future illustrates the possibilities.
In the thirty years between 1991 and 2022 Canterbury’s population grew by 50% to 655,000 people (Stats NZ). Greater Christchurch makes up over 80% of the province’s population. The city is New Zealand’s second largest metropolitan area and second city to reach a population greater than ½ a million (assuming Greater Auckland is considered just one metropolitan city).
New Zealand has five regions that make up 77% of its total economic activity. The upper North Island ‘golden triangle’ makes up half the economy — 52.1% up from 49.1% in 2001. This consists of Auckland 37.3%, Waikato 8.9%, and Bay of Plenty 5.9%. The fourth region is Wellington has 12.6% of New Zealand’s total economic activity — down from 15.2% in 2001. The fifth region is Canterbury which also has 12.6% of the nation’s economic activity — up from 11.6% in 2001. No other region exceeds 5% and these other regions have declined from 24.1% to 22.7% of economic activity between 2001 and 2021 (Source).
Given these population and economic growth figures Greater Christchurch is a significant place with growing importance to New Zealand.
It is conceivable given Canterbury’s historic growth pattern that over the next 30 years Greater Christchurch’s population could increase by another 50% to ¾ of million people, and over 60 years double to 1 million people or even higher (note — a 50% increase from 750,000 would actually be 1,125,000 people).
This is not a prediction that population or economic growth will occur or even to make a value judgement that this would be a good thing. The point is if population growth does occur then policies and plans should be prepared for it.
There are many factors that influence whether a city grows strongly or not, not least people’s right to freedom of movement.
A key factor for a city’s success is having great networks — both physical (such as water supply infrastructure, road networks, congestion free transit systems etc.) and social (that connect people for their various recreational, business, health and other needs, such as, systems to share and advance knowledge).
It is vitally important that these city networks are inclusive for newcomers and for the next generation.
Christchurch in the future might gain or not from people migrating to New Zealand’s larger cities — this urbanisation pattern has been observed internationally for several centuries now. It is so strong for some cities — like Tokyo — that city growth is positive while national population growth is negative. Demographic growth rates over a 30-to-60-year time period might change — for instance, it is possible that future generations might have more children (i.e., the birth rate might increase). Conversely New Zealand might have a net migration loss or gain, and Christchurch might gain or not by the movement of peoples within New Zealand.
In the future Christchurch might experience the movement of peoples due to environmental rather than economic reasons, such as, natural disasters and climate change disruptions — both within New Zealand and overseas, that cause managed retreat from some areas and demand for expansion in other areas.
Climate change is likely to have a huge impact on global migration patterns — which will affect New Zealand and Christchurch. But not to be forgotten is the possibility of further tectonic activity. The Alpine fault erupts fairly regularly every 300 years or so. It is due for another event. The 2010/11 Christchurch earthquakes destroyed 28,000 homes. Whole suburbs were permanently evacuated (red-zoned) and new suburbs were built. New Zealand because of its geological make-up will experience similar events fairly regularly — something like once in a lifetime somewhere in New Zealand a town or city will be majorly damaged from tectonic activity.
There are many other possible factors that might affect the future size and shape of Christchurch. As the saying goes, there are known known factors, known unknown factors, and unknown unknown factors.
Ultimately bottom-up choice will trump any prescriptive top-down plan for Greater Christchurch’s population. Christchurch is part of the common Australasian labour market whereby people are free to move as opportunities present themselves. There is a large number of New Zealanders in Australia — perhaps as many as 500,000 people — 10% of New Zealand’s population, which are free to return at any time.
For longer timeframes, such as, thirty-to-sixty-years it is not possible for predictions to be truly accurate. At best they are educated guesses probably based on extrapolating earlier trends. See my paper — Great Cities have Great Networks for a discussion on why soft-touch planning that can adapt to multiple future scenarios would be beneficial.
Because of the difficulties discussed in this paper New Zealand policy makers have a pattern of over and under estimating population growth. For long term planning purposes, such as the creation of city spatial strategies, policy makers should have a strategy that can cope with a range of different growth (and no-growth) scenarios.
Final Thoughts
In a sense this is the third paper of a four-part series.
The first paper outlined the general characteristics of what makes a city great — it is called Great Cities have Great Networks.
This second much shorter paper discusses Possible Future Population Growth Scenarios for Christchurch and Canterbury.
The third paper — What Shape Will Christchurch Become? — examines Greater Christchurch’s draft spatial strategy to determine whether the metropolitan area has the capacity to become a great city and found it probably doesn’t — but a few relatively simple additions to the strategy could easily fix this.
The fourth paper which I have yet to start would look at a specific plan to fix the Greater Christchurch spatial strategy so that Christchurch has the capacity to become a great city with great networks. This paper will examine new transit-oriented development (TOD) tools, institutions, and policies.
