Perth's Population Explosion

Long-range forecasting is a necessary part of planning but is always fraught with difficulty. For that reason, land use and transport planning should be on the basis of managing risk and uncertainty rather than a single projected value (or even range of values) for population.

It is of some concern, therefore, that newly-released population forecasts for Perth are substantially higher than those used as the basis for Directions 2031, the major strategic planning guidance for Perth.

Directions 2031

Directions 2031 was based on a Perth population of 2.40 - 2.88 million by 2031, with a longer-term expectation of 3.5 million by 2050.

The new forecasts from the Australian Bureau of Statistics show a range of 2.7 - 3.1 million (+12.5% on Directions 2031) for 2031 and 3.9 - 5.4 million (+15% to +50% on Directions 2031) by 2050.

Australian Bureau of Statistics 

Such a large increase in medium-term and long-term population expectations does not simply mean that current plans can be accelerated. All development, including transport infrastructure, has a long lead time, which means the acceleration required is effectively even more rapid than the population forecasts imply.

Acceleration will also mean that there is a great temptation to rely more heavily on the 'easy' fixes - those that can be accelerated most readily - rather than those that are more suitable for growth but are more difficult to implement quickly.

Directions 2031 sets a target of 47% of new dwellings to be created as infill in existing developed areas. This was a reduction from 60% from the previous Network City. Any further reduction, even in the short-term, to accommodate more rapid growth would increase distances people have to travel and add to congestion and the cost of travel.

More fundamentally, forecasts of a larger-than-previously-anticipated population growth for Perth raises the question of whether such a size and rate of growth is desirable and, if not, how it can be influenced.

In transport, predict-and-provide is increasingly being replaced by demand-management, but one of the prime determinants of travel demand, population, is still regarded as a given. Perhaps it is time for both land use and transport planning to consider Perth's population growth as something to be influenced rather than as a given that is beyond our control.