Building cities for a changing climate

Our cities are responsible for a large chunk of the world’s greenhouse gas emissions, so the way we plan and construct them has to adapt to the future impacts of climate change.

Worldwide, buildings are responsible for 19% of greenhouse gas emissions and our cities are responsible for up to 70%.

So, designing buildings that produce fewer greenhouse gas emissions is vital to help limit global warming and the threats it poses. But we also need to ensure buildings are designed and constructed to cope with our changing climate conditions to bolster their longevity.

This means the construction sector has a significant role to play in mitigating and adapting to climate change.

The urgency of rapidly reducing greenhouse gas emissions was highlighted in the bleak prognosis from the recent Intergovernmental Panel on Climate Change (IPCC) special report.

The IPCC report, released last year, states that “limiting global warming to 1.5°C would require rapid, far reaching and unprecedented changes in all aspects of society”.

This includes changes in the way cities currently function, including land use, energy, industry, buildings and transport.

Our research identifies several barriers inhibiting the construction industry’s response to adapting to climate change.

The current regulatory framework is a key hurdle that many stakeholders within the Australian construction industry raised in our interviews. The National Construction Code doesn’t explicitly address climate change.

Updating the regulations is an opportunity to set new benchmarks for the industry. The National Construction Code and its associated standards need to be reviewed and strengthened to ensure climate change adaptation and mitigation are addressed.

In the absence of any updated regulations, another barrier is the lack of client demand for buildings to be designed and constructed to address climate change. This sits alongside the perceived additional cost of building and including these mitigation and adaption measures.

Australia’s National Construction Code doesn’t explicitly address climate change.

Yet many people we interviewed say better regulation to address climate change would be beneficial. This would create a ‘level playing field’ for the industry and encourage innovation in the sector.

Significant climate change impacts will happen within the life cycle of buildings that are being constructed now. So it’s important to design for these changes today.

For example, considerations need to be made now to ensure gutters and drains are built to a size that can cope with bigger rainfall events, and to ensure that our homes stay cooler for longer during increasingly hot summers.

Preparing for our new extremes

Unless we rapidly reduce our greenhouse gas emissions, we will all face significant and catastrophic impacts including increasing drought periods, a spike in the number of extreme heat days, increasing rainfall intensity and a rising number of extreme events like floods, cyclones and bushfires.

These changes will influence the way our economy and society function.

To limit warming to 1.5 degrees (above pre-industrial levels) by 2100, and to limit climate change impacts, we need to reduce our global greenhouse gas emissions, fast — to 50% by 2030 and net zero emissions by 2050.

As the IPCC’s special report says, achieving this goal will require a rapid transformation of our urban infrastructure systems including transport, the layout of our cities, and the design and construction of buildings.

If we construct buildings that are unable to withstand future weather conditions, we’ll need more electricity to heat and cool our homes and workplaces.

Ignoring future climate change in construction will mean many buildings become redundant.

But where we build will also be important; the further out, the more likely we’ll see more transportation-related greenhouse gas emissions, like travel modes for work and leisure. We will need to facilitate city growth on sites that aren’t vulnerable to future risks such as sea level rise.

In addition, risk to operational capacity and building obsolescence will become key considerations for owners and occupiers alike, requiring forward planning and construction of buildings to withstand and cope with future challenges.

Australia is going through a significant period of population growth. This translates to a large volume of construction, like dwellings and associated urban infrastructure, which is underway in many parts of the country.

It’s critical the construction code is updated to ensure that new buildings going up now address the changes we know are occurring and will continue to escalate in the future.

Ignoring future climate change in construction is likely to end with many buildings and infrastructure projects becoming redundant, expensive to run or maintain, or even uninhabitable. This creates a plethora of problems for current and future generations.

Our research found all disciplines involved in creating a built environment have a role to play in addressing climate change — architects, urban designers, planners, engineers, builders and constructors are all integral to making a change.

Understanding how these sectors integrate and influence each other, and how they operate within policy and regulatory frameworks, is crucial to reduce greenhouse gas emissions and so limit the harsh consequences of irreversible climate change.

The research was conducted by Dr Anna Hurlimann, Professor Valerie Francis, Dr Georgia Warren-Myers and Dr Geoff Browne from the University of Melbourne’s Faculty of Architecture Building and Planning. It was funded by The Multiplex Research Program Award.

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