In defense of population growth

Growth: what is it good for?

Accommodating a growing population can certainly be challenging. It means having to find more money to invest in transport and water infrastructure to enable new residents to live and travel in the city. As Auckland Council’s recent consultation on the Long Term Plan shows, asking people to pay more is never a very popular proposition – even if they like how the money’s being spent.

And, as Stu pointed out in his post on Auckland house prices this Monday, population growth can also put pressure on housing markets. Multiple research papers from the Reserve Bank have shown that increases in net migration tend to be followed by increases in house prices – shown in this chart. Obviously, homeowners do quite well out of this, but others face added costs:

In short, it’s not surprising that some people feel trepidatious about population growth and migration. And it’s not surprising that those anxieties are especially present in Auckland, which is projected to continue growing rapidly over the next three decades.

While unease about population growth is understandable, I’d argue that it’s misplaced. In my view, the benefits of urban population growth in New Zealand far outweigh the costs. While large urban areas can become dysfunctional – think of Beijing’s astonishing smog problems or the high cost of infrastructure in sprawling American cities – New Zealand’s cities are nowhere near large enough for the diseconomies of scale to triumph over the economies of scale.

This is easy to see if we look at the periods when Auckland hasn’t been attracting migrants. Here’s a chart from a presentation on Auckland’s demographics by Auckland Council social researcher Alison Reid. It displays the composition of Auckland’s population growth since 1922. In recent decades, natural population increase – i.e. people having babies – has been the biggest source of growth. Net migration is important, but it can be quite volatile – surging up and then crashing back.

What stood out to me from this chart was that the years with little or no net migration to Auckland have not been good times for the city. Net migration slowed to a trickle during the Great Depression, and turned negative during the constrained years during and after World War Two. More recently, quite a few people fled Auckland during the economically calamitous Muldoon years. Net migration remained low during the painful adjustments imposed by the following two governments.

I wasn’t living in Auckland during the 1990s – my parents had joined the queues leaving via Auckland airport – but friends who were say that the city was turning into a ghost-town. History shows that shutting off the migration tap has never led to a better, more vibrant city or more opportunity for residents. It’s simply been a sign of failure.

My hypothesis is that New Zealand has a strong feedback loop between net migration and economic growth. When growth prospects get worse – as they did in the 1970 and 1980s – it dissuades people from coming here and encourages Kiwis to leave for greener pastures. This in turn worsens growth prospects by sucking consumer demand out of the economy and reducing perceived household wealth (i.e. lowering house prices).

By contrast, good growth prospects tend to attract migrants to New Zealand’s cities and encourage potential emigrants to stay. This in turn leads to a virtuous cycle between higher growth and increased migration.

We can’t fully control this process, as it depends in part on what’s happening in Australia and the rest of the world (not to mention macroeconomic variables that we don’t fully understand). But we can make sure that our cities are in a good position to take advantage of population growth.

The first, and most important thing we can do is to build better cities that are able to attract and efficiently accommodate more people. In Auckland, for example, we’ve got some challenges, including transport investment that’s been heavily skewed towards cars (and only cars) and rising house prices. But the flip-side of those is that we’ve got great opportunities to:

• Improve transport choice by investing in Auckland’s “missing modes” – a frequent bus network throughout the city, rapid transit infrastructure, and safe walking and cycling infrastructure
• Improve housing choice by providing opportunities for people to develop higher-density residential typologies in market-attractive areas
• Invest in great public spaces, such as Auckland’s waterfront and increasing numbers of shared spaces.

Second, as we attract more people to our cities, we need to accommodate them in an efficient and environmentally responsible way. This means enabling people to live in areas that are accessible to jobs, shops, and other amenities. As I found when I looked at carbon emissions from commutes in New Zealand cities, people in inner-city areas are considerably more environmentally friendly than their co-workers from the urban fringe.

Moreover, the data shows that increasing density can be a positive-sum game for existing communities as well as for the environment. At the city level, we can’t observe any relationship between rising population densities and congestion – fears of traffic-choked streets just don’t seem to have materialised in practice. (So much for diseconomies of scale!)

On the other side of the ledger, suburbs with higher population densities have better consumption choices. Many of the services that people rely upon – from vege shops to Japanese restaurants to public transport to roads – exhibit strong economies of scale, which means that they get better when there are more people around.

Which suggests that there is also a third important thing that we need to do, which is to tell good stories about the opportunities that urban growth will offer us. New Zealand’s used to thinking of itself as a rural economy with some cities sprinkled around as afterthoughts. That’s a dated and inaccurate self-image when over half the economy is located in our three largest cities.

So, what’s your perspective on urban growth?

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