Sign in

Can Our Resilient Infrastructure Goals be Achieved in a Low Carbon Manner?

IS THOUGHT LEADERSHIP - RESILIENCE | James Hughes - Climate and Resilience Specialist at Tonkin + Taylor 

“It has been recently reported ‘that 75% of the infrastructure that will exist globally in 2050 has not yet been constructed”’. Consider that for a moment.

As more people move to cities (currently around 55% globally live in cities, and projected to be 70% by 2050), and these cities densify, more vertical and horizontal infrastructure will be required. Add to this, legacy issues of poorly designed and end-of-life systems that need renewing, and increasing expectations relating to levels of service, and environmental performance – and one can easily envision the scale of the challenges we face.

These challenges are amplifying right now, as throughout NZ and Australia, infrastructure investment is accelerating significantly, as Governments attempt to jump start economies as a response to COVID-19 impacts.

Also, and importantly, Governments and Councils are increasingly taking a focus on reducing emissions. For example, NZ’s Climate Change Commission has just released their draft advice on how the country should reduce emissions in line with international commitments to limit warming to 1.5 degrees. These factors present massive challenges for all our infrastructure sectors, particularly those that rely predominantly (and historically) on ‘hard engineered’ solutions. By this I mean, those that may rely on energy intensive mechanical and electrical systems (e.g. pumping, heating, cooling) or physically engineered structures (often made of steel and concrete, with high embodied carbon emissions).

If we now circle back to the quote at the start of this piece - it is therefore imperative that new infrastructure contributes to achieving our climate change targets and is ultimately ‘low carbon infrastructure’.

But what is low carbon infrastructure, and how do we reconcile the various drivers mentioned above at the scale and pace required? This no doubt will require careful planning and strong leadership. If there was any time in history to pause and consider ‘how’ and ‘on what’ we spend on infrastructure, now is it.


The physical risks from climate change are increasingly well understood in Australia and now in New Zealand (following the release of the NCCRA). Rising sea levels, increasing extreme events, higher temperatures, drought and bushfire all pose risks to existing communities, and this risk is predicted to increase over time. Central and local government leaders are grappling with decisions on whether to defend, accommodate or in fact move away from at-risk areas, and must weigh up costs and benefits of doing so in each individual case.

A challenge in densely populated areas is that the cost of relocation is prohibitive, and therefore defending/accommodating the increasing risks will likely become the only tenable response.

Therefore, the choice of how we invest in future infrastructure solutions to enable our communities to live in a more volatile and uncertain natural world then becomes a key question. Should we build higher (and higher) sea walls, and ‘hunker down’; do we anticipate and prepare ourselves for more frequent and intense events, and deal with the consequences (‘clean up’) afterwards; do we pack up and move; or can we move to more flexible and agile ways of living with nature in a more volatile world?


The most recent Intergovernmental Panel on Climate Change (IPCC) special report SR15 (2018) confirms we must target 1.5°C with ‘no or limited overshoot’ and underscores the need for urgent and transformative climate action, as impacts increase in scale, frequency and intensity.

IPCC SR15 highlighted the concept of the ‘carbon budget’ which is the total amount of carbon equivalent which can be emitted in order to limit warming below a threshold. In order to have a 66% chance of staying below 1.5°C, the remaining global carbon budget is around 420Gt CO2e and it is estimated that this budget will be used up in approximately 8 years at current emissions levels. IPCC states ‘the world has already witnessed about 1˚C of temperature rise and is on track to exhaust the carbon budget associated with 1.5˚C by 2030’.

Efforts to meaningfully achieve emissions reductions targets will have particular implications for cities and infrastructure providers, given a large portion of people live in cities in Australia and NZ, and as a result generate a significant volume of emissions.


Cities play a vital role in driving carbon emission reductions for their communities. As presented in the recent C40 Cities report “Cities can deliver or influence just over half of the savings needed to put cities on a 1.5 degree trajectory - either through direct action or via collaboration with partners such as the private sector”.

They also have a role in ensuring current and future communities are resilient to natural and climate hazards – through, for example, land use planning, flood management infrastructure, and controlling / managing growth and the development of new communities.

In order to reconcile the need for both building resilience and delivering a low carbon future – three key points are discussed below, in relation to the various phases of ‘city building’ – planning, design, construction and operation/maintenance:

Why we build: When planning for growth and renewal in out cities, we firstly must consider why we need to build at all. Can alternatives to new infrastructure provision be explored? This may mean building nothing at all, investigating opportunities for demand reduction, or behavioural change.

Where we build: It is vital that we build new communities and associated infrastructure in areas that have acceptable (low) levels of exposure to future climate hazards.  This would mean in areas outside of known flood plains, or areas exposed to coastal erosion or inundation. While this sounds simple, there are numerous examples of new developments occurring in potentially hazardous areas. Building in less-hazardous areas lowers the need for protective infrastructure which can often be both costly and high-carbon.

Additionally, we need to think about the urban form of our communities. Given that transport often contributes the greatest proportion of carbon, this is a key opportunity for reduction – and requires a focus on improving our urban form (compact cities) – to enable residents to use lower emission transport options such as public transport and active modes.

What and how we build: The method of infrastructure construction can influence the emissions generated through the construction process and the type of infrastructure can influence the emissions generated from the operations and maintenance processes. The biggest opportunities for reducing capital carbon are early on in design and planning processes. Operational carbon requires thinking about energy use for mechanical equipment, and how systems are renewed in the future.


Going forward, our Councils and infrastructure providers must integrate climate adaptation and carbon reduction into all decisions regarding infrastructure. Inherent within the complex decisions that need to be made will be a range of trade-offs and value judgements. However, the more we make these decisions transparent and explicit, and base them on the most recent science, the more communities can usefully and proactively participate and engage in achieving more sustainable and resilient outcomes.
Basel (2019).
In NZ and Australia, around 85% live in urban areas.
NZs first National Climate Change Risk Assessment
Deadline 2020: how cities will get the job done (C40)