Turning urban sprawl into a net-zero city. Lessons from Melbourne

The focus by leaders at COP26 understandably rested on national issues within a global context. But the growth of cities cuts across national lines. In particular, the sprawling cities of the southern hemisphere, exacerbate the climate crisis and threaten the social and financial health of urban communities. By 2050, 70% of the world’s population will be living in cities. They cannot be overlooked.

If urbanization is to be a positive step towards developing a net-zero city, the process needs to be well thought out and planned instead of the result of speculation and informal settlements.

For urbanization to have social, environmental and financial benefits, the following six factors are crucial:

Urban settlements need to be built at a density that creates a critical mass capable of supporting the essential services of a community such as public transport, social and commercial services. Without density we simply produce dormitory residential areas requiring a car based transport solution devoid of the essential services that make places work. This results in social isolation with high personal and living costs.

The second essential is that these areas need to be mixed use where the local community can access all that they require for their daily lives within a 20 minute walk. Mixed use is not only essential for ease of access and it ensures that the expensive infrastructure, required for successful urban areas, is used to its optimum by eliminating the peaks and troughs of single use neighbourhoods. Remote working during COVID has illustrated how mixed use is essential to making our local areas more accessible and liveable. It can also assist in lowering congestion and saving time spent on lengthy commuting trips.

Communities need to be well connected allowing easy access both locally and within metro areas. This will allow for a better balance between all modes of transport and help to transition away from a car based society. Streets, which make up 80% of the public space in cities, can become more people oriented, as is the case in the compact cities of the northern hemisphere, that produce healthier, better activated street life.

With density, mixed used and well-connected people, the public realm improves. Streets with sidewalk cafes and trading, tree lined roads and widened footpaths will be places to dwell in rather than simply rush through. Streets are where we should live out our democratic and social experiences. They should be inclusive spaces that are safe and vibrant and places where we meet, trade or simply observe daily life.

Importantly, as we build these places they need to be built in harmony with their location. They need to reflect the local climate and aesthetic that results from a low energy response to building local character. Generic solutions that depend on shipping, air conditioning and that all look the same are in opposition to net zero ambitions. Previous generations and communities innately understood problems and built simple solutions – we should learn their lessons in designing our future buildings.

Finally we need to realize that we already live in cities that are poorly adapted to net zero living and need to employ adaptability to achieve the essential characteristics listed above. Incremental adaptation has seen Melbourne convert outdated office buildings into residential apartments, asphalt into open space and widened footpaths to turn urban heat island into an urban forest.

These six key moves can change our cities dramatically at low cost for better social and economic outcomes.

State and local governments – as well as urban planners – can implement these and further elements. Changing cities is often seen as a slow and costly process without quick results, so politicians and their advisors tend to avoid it.

Sprawling cities in the Southern Hemisphere are similar in many ways, even though they may exist within different economic and social frameworks. Many were planned as colonial cities: a grid pattern with a strong central core surrounded by sprawling suburbs, each served by a local activity centre with retail and local services.

In Melbourne’s case, a city of 5 million, research has shown how the doubling of population could be accommodated on only 7.5% of the existing metropolitan land and by buildings in areas not exceeding 5-8 stories in height. The 7.5% of land is located along transport corridors, around rail stations, in activity centres, and on grey field sites.

The cost savings of greater utilization of existing underutilised infrastructure would be AU $1.1 billion for every 1 million people added to the metro area.

There would be no further need to consume rich agricultural land on the city fringe, or to place communities in areas where there are limited services, remote from employment, requiring families to own multiple cars to access the services they need. These areas place an increasing number of families in social and financial stress due to high mortgage and petrol prices, Griffiths University researched.

In contrast, over the last 35 years Melbourne’s well connected central city has concentrated on increasing its density, producing a better balance of uses, and adapting its public realm by converting 80 hectares of asphalt into widened footpaths. This has led to open space and trees along streets. It promotes walking, cycling and public transport.

Melbourne has become one of the world’s most liveable cities, where current inner city rental prices are among the lowest in the country. This, combined with reduced commuting times and the redundancy of a car, make the central city one of the most affordable inner cities in Australia.

The switch from sprawling cities to compact cities is dependent on national leadership. It is not difficult, but much rather essential, if our cities shall become sustainable, socially cohesive and economically successful.

The task, as illustrated above, does not require changes to the whole metropolitan area but to approximately 7.5% of our cities - areas close to public transit corridors and around existing activity centres.

The remaining 92.5% would see incremental changes such as rooftop solar, localized batteries, water catchment and urban forests. Melbourne is doing all of this already.

These combined with increased cycling, walking and the new trackless trams developed in China are seeing the cost of sustainable infrastructure reduce and become more accessible and resilient. Our suburbs could become extended green wedges retaining many of the essential characteristics for which they are valued.

Central Melbourne has shown the way and spent the last 30 years on this transition. If the next 30 years were spent transitioning our metro area and other cities followed suit, the journey to net zero would become more achievable. As a byproduct, our cities would become more liveable.

Alongside the commitments given by leaders at COP26 to save our forest, there needs to be a commitment by leaders to aid and empower cities to grow – according to the known ingredients of net-zero and liveable cities.