«Infrastructure Australia is an independent statutory body that is the key source of research and advice for governments, industry and the community ...»
and Australian Infrastructure
Audit Background Paper
Australian Infrastructure Audit
2 Population Estimates and Projections Australian Infrastructure Audit Background Paper
Infrastructure Australia is an independent statutory body that is the key source of research and advice
for governments, industry and the community on nationally significant infrastructure needs.
It leads reform on key issues including means of financing, delivering and operating infrastructure and how to better plan and utilise infrastructure networks.
Infrastructure Australia has responsibility to strategically audit Australia’s nationally significant infrastructure, and develop 15 year rolling infrastructure plans that specify national and state level priorities.
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Executive Summary Introduction This paper provides an overview of various population projections for Australia, the eight states and territories, their capital cities, and some regional areas over the next 15 to 40+ years. The paper has been prepared to inform the Australian Infrastructure Audit and subsequent development of the Australian Infrastructure Plan.
The purpose of the paper is to consolidate authoritative data on population issues in order to minimise the potential for misunderstanding of the demographic drivers of future demand for infrastructure.
Developing a solid understanding of population projections is important for a range of reasons. Firstly, population growth is a key driver of economic growth. The so-called ‘three Ps’ model of economic growth - population, productivity, and participation - applied by the Australian Treasury and others has population at its core.
Secondly, projections of the demand for infrastructure services, and in turn the business cases for new capital and maintenance proposals, turn heavily on population projections. Misunderstanding population projections can lead to poor infrastructure-related decisions.
Finally, population not only adds to demand for infrastructure; it can also provide funding for infrastructure. A larger population, gainfully employed, can afford more.
Australia’s Present Population Australia’s population at the end of September 2014 was estimated to be 23.58 million persons. The four most populous states were: New South Wales (7.54 million and 32.0% of the national total); Victoria (5.87 million; 24.9%), Queensland (4.74 million; 20.1%) and Western Australia (2.59 million; 11.0%).
Two-thirds of Australians live in the capital cities. Western Australia, South Australia and Victoria have the highest concentrations of population in their capital city (all 75% or more), while Tasmania and Queensland have the least (both under 50%).
Natural increase in the population has ranged between 114,000 and 162,200 persons per annum over the last 20-25 years. Recently, net overseas migration (NOM) has played a more significant role in national population growth, with net figures between 200,000 and 300,000 persons per annum since the mid-2000s.
Projected Population Growth Over recent years, Australia has had one of the fastest population growth rates in the developed world (it grew by 1.49% per annum over the 15 years to June 2014). Long-term population projections released by the Australian Bureau of Statistics (ABS) in November 2013 suggest that, on ‘medium’ assumptions,
Australia’s population will grow from 22.7 million persons in June 2012 to:
30.5 million in 2031 (an increase of 7.8 million persons or 1.56% per annum);
41.5 million in 2061 (an increase of 18.8 million persons or 1.24% per annum); and Population Estimates and Projections Australian Infrastructure Audit Background Paper 7 53.6 million persons in 2101 (an increase of 30.9 million or 0.97% per annum).
The latest projections are somewhat higher than the equivalent figures released in 2008. The previous projected populations for 2031 and 2061 were 28.8 million and 36.7 million persons respectively. The new medium level projection for 2031 (30.5 million persons) is not that different to the previous high level projection (30.9 million).
This increase in the projected population reflects both recent natural growth in population as well as higher levels of net overseas migration. The new medium level projections assume net overseas migration of 240,000 persons per annum, 60,000 persons more than the 2008 projections. The assumption on net overseas migration is the largest and most uncertain, both in terms of the aggregate number and the distribution of future migrants between the states and territories.
Projections of Australia’s population used in the 2015 version of the Intergenerational Report are very close to those issued by the ABS in November 2013. The 2015 Intergenerational Report provides a projection for 2034-35 (32.0 million persons), i.e. the closest year to 2031 (the year of interest in the Audit). The medium level ABS population projection for June 2035 is also 32.0 million.
The proportion of Australians living in capital cities is expected to grow. The medium projections suggest that Australia's capital cities will increase their share of national population from 66.0 per cent in 2011 to
69.3 per cent in 2031 and 73.4 per cent in 2061.
This view is consistent with those of several state governments (e.g. New South Wales, Victoria and South Australia) that are planning for their capital cities to take on a greater share of the state’s population.
The medium level projections suggest that 78.4 per cent of Australia’s population growth over the period to 2031 could occur in the cities. The equivalent percentage for the period to 2061 is 82.1 per cent. On
these medium projections, the population of Australia's capital cities would grow by:
6.4 million persons between 2011 and 2031; and 15.7 million persons between 2011 and 2061.
The projected growth in the population of the capital cities between 2011 and 2031 is equivalent to a new Melbourne and Brisbane. The projected growth to 2061 is more than the total current population of the capital cities.
The population of a number of major cities outside the capitals, e.g. Geelong, Bendigo, Ballarat, Newcastle (or more precisely the Lower Hunter), the Sunshine Coast and Gold Coast in Queensland (and possibly Rockingham and Mandurah in Western Australia), is also expected to grow appreciably. Several of these cities are in ‘peri-urban locations’ that are relatively close to the capitals and share many economic and social linkages.
Over time, as these peri-urban cities grow, it is conceivable there will be greater interaction between the capital and the city in question. In the absence of employment growth in these locations, ‘journey to work’ trips to and from the capital city may increase appreciably.
Performance of Previous Population Projections Projecting population growth over the long term can be challenging. Examining the performance of past projections provides an insight into how future projections may perform.
Population projections for Sydney based on the 1981 Census suggested a 2011 population which was only
3.2 per cent (142,000 persons) lower than the observed estimated resident population (ERP) in 2011.
Similarly, the 1981 population projections for Adelaide in 2011 were 4.8 per cent lower (58,000 persons) than the observed ERP in 2011. A previous projection of Queensland’s population in 2011 was only 4.0 per cent (174,000 persons) lower than the observed ERP in 2011. Given the length of time over which these projections were made, the margins of error provide some encouragement for future projections.
Projections for Western Australia show a different result. The projection for 2011 was 14.4 per cent (230,000 persons) lower than the observed ERP. However, the 2001 projection was off by less than 1 per 8 Population Estimates and Projections Australian Infrastructure Audit Background Paper cent. The difference in the following ten years is almost certainly due to the impact of growth in the mineral and energy sectors in the period after 2001.
More recent population projections for Melbourne also appear not to have fully anticipated a period of very strong economic growth. The Victoria in Future projections, based on the 2001 Census, anticipated a 2011 population for Melbourne of 3.87 million persons. In contrast, the observed population was 4.17 million by 2011, a difference of 294,000 persons (7.6 per cent) in less than a decade.
Examining the performance of these past long-term projections has shown that they can prove to be reasonably accurate, but are susceptible to inaccuracy should periods of strong economic growth develop in the future.
Implications for Our Infrastructure Networks Projections are simply that; projections of future population given certain assumptions. Change the assumptions, and a different set of projections arise. They are used to inform forecasts and plans.
Arguably, greater weight should be placed on the forecasts and plans themselves. This is because they are expressions of intent and/or design, reflecting decisions and commitments by various parties.
Government plans are usually (but not always) based on population projections that, at a state/territory level, accord fairly well with the medium growth ABS projections.
Governments and others may advocate other plans and strategies that, if implemented, would lead to materially different population figures from those suggested by current projections. This is particularly the case at a sub-national level. For example, the Australian Government has committed to developing and implementing a strategy to grow economic activity in northern Australia. Also, state government projections for New South Wales and Victoria suggest greater population growth in regional areas than anticipated by the ABS.
Demand for infrastructure does not necessarily rise or fall in proportion with changes in population.
Nevertheless, in the absence of changes in the per capita consumption of infrastructure services and/or an ability to manage demand for those services within existing assets, the recent and prospective growth in Australia’s population suggests a rising demand for new infrastructure.
The projected growth in population will have significant implications for our infrastructure networks.
Given the ‘fiscal gaps’ projected in various versions of the Intergenerational Report (and equivalent reports prepared by some states), funding (or otherwise meeting) the projected requirements for infrastructure will almost certainly require significant policy change.
Within the cities, the location of new development and population growth will be critical. While the cost of providing new infrastructure in ‘greenfield areas’ is substantial, the cost of retrofitting or augmenting some infrastructure (for example transport links in tunnels) in established areas can also be high.
With a few exceptions, the ‘population case’ for expanding infrastructure networks in regional areas is likely to be less obvious. Arguments for investment in infrastructure in those areas will be driven more by social considerations (service equality) and economic development prospects, e.g. proposals for development in northern Australia.
Approach Pursued in the Audit The ABS estimates and projections are a starting point for analysis during the Audit, particularly at a national and state/territory level. The ABS projections are also used as a starting point by state and territory governments, as well as other bodies such as the Australian Treasury.
In developing sub-state/territory projections, a balance has been struck between, on the one hand, having a set of projections that is sufficiently disaggregated to inform meaningful discussions about an area’s infrastructure needs and, on the other, having a level of disaggregation that is manageable to deliver. The Audit uses sub-state/territory projections at the ABS-defined Statistical Area (SA) 4 Level. This is the first level of disaggregation below the state/territory level. There are 88 SA4 areas across Australia. In some cases, e.g. when analysing urban transport, a finer grain of analysis (SA3 or SA2) has been applied.
Population Estimates and Projections Australian Infrastructure Audit Background Paper 9 The projections used in the Audit are consistent with those used in the recent Northern Australia Infrastructure Audit prepared by Infrastructure Australia. Given the nature of that work, in some cases estimates and projections were prepared at the ABS SA2 level.
10 Population Estimates and Projections Australian Infrastructure Audit Background Paper 1 Introduction The Australian Government has asked Infrastructure Australia to prepare an Australian Infrastructure Audit (the Audit), and subsequently to assist the Government in preparing an Australian Infrastructure Plan (the Plan) for the development of Australia’s infrastructure.