Climate change risk and the built environment

This Issue This is a part of the Net-zero carbon buildings feature

By - , Build 182

A government-level report into the impacts of climate change on New Zealand, including our built environment, will help councils, communities, infrastructure providers and others to begin making plans to mitigate risks.

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Figure 1: A strategic approach to climate adaptation.
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THE NATIONAL CLIMATE change risk assessment for New Zealand (NCCRA), published in August 2020, provides a national overview of how New Zealand may be affected by climate change-related hazards.

It was delivered by a broad team of experts on behalf of the Ministry for the Environment and followed an assessment framework previously developed by the Ministry.

Risks and opportunities

The NCCRA identifies the main climate risks and opportunities, highlights information gaps and helps identify where adaptation action is required. It also provides a very useful resource for councils, iwi, infrastructure providers, key business sectors, the social sector and communities – assisting them to understand and address the risks they face.

The risk assessment will be used to develop a National Adaptation Plan to be published towards the end of 2021 that will outline the government’s strategy for building resilience (adapting) to the identified priority risks.

The risk assessment groups risks according to five value domains – human, natural environment, economy, built environment and governance. While many of the risks are interlinked, these groupings are useful as they help identify risk owners – those who have a role in managing the risk over time.

Eight priority risks for built environment

The eight priority risks for the built environment cover risks to critical infrastructure sectors as well as to buildings (see Table 1). A number of these first-order risks can cause cascading or second-order risks to communities, ecosystems and the broader economy.

Many of these risks relate to water – either too much, leading to flooding and erosion, or too little, leading to drought.

Table 1 Summary of built environment risks

Risk of flooding

Extreme flood events are projected to increase around New Zealand, with estimates of up to an 11% increase in the 1 in 10 year, 1-hour duration storm by 2040 and up to a 34% increase by 2090 on average across the country under RCP8.5. RCPs (representation concentration pathways) predict how concentrations of greenhouse gases in the atmosphere will change in the future as a result of human activities. RCPs range from very high (RCP8.5) through to very low (RCP2).

On-going sea-level rise also contributes significantly to both coastal and inland flooding, exacerbating coastal storm tides, which in turn lead to more frequent and severe inundation of coastal areas.

It is estimated that, by 2050–2070, extreme sea levels that are expected to be reached only once every 100 years on average at present-day mean sea levels will occur at least annually on average. Sea-level rise is also predicted to lead to groundwater rise in some coastal areas, creating an additional hazard for communities and councils to consider.

Increased flood exposure leads to risk for infrastructure, buildings and structures. This may relate to temporary disruption or even damage and destruction of buildings, potentially requiring relocation from at-risk locations in the future. The failure of drainage systems in urban areas – due to capacities being exceeded – and the potential overtopping and breach of stop banks is also a known risk to the built environment.

The ability to adapt existing buildings in a cost-effective manner is limited, as buildings are generally designed to be long-standing permanent structures served by complex infrastructure systems.

Those with suspended timber floors could be modified, making them more adaptable than buildings that have concrete floor slabs. This fact raises important questions for how we design buildings within areas that may be exposed to flooding presently or in the future.

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Risk of droughts

Another key risk is that of drought, which will impact on potable water supplies throughout New Zealand as well as contribute to increased fire risk. Recent droughts have had major impacts on water supplies around New Zealand – particularly those in Auckland and Northland.

Water New Zealand’s annual performance reviews indicate that, since 2014, around 50% of councils (on average) report that they have implemented some form of water restriction within communities. This is a significant proportion and underlines the seriousness of this risk to councils and communities and is further complicated by low levels of household metering in some areas and broader under-funding of systems. This inhibits the ability to effectively manage leakage and demand levels.

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Other challenges

These flood and drought-related risks currently pose major challenges for communities, councils and infrastructure utilities, and these challenges will grow over time if not addressed soon.

Other challenges include the ability to retain insurance, as explored in a recent Deep South Science Challenge study Climate change and the withdrawal of insurance (see www.deepsouthchallenge.co.nz), and how well our institutions respond to climate change, particularly in terms of governance.

One of the key governance risks identified within the NCCRA was that climate change impacts are exacerbated because current institutional arrangements are not fit for adaptation. This includes legislative and decision-making frameworks, coordination within and across levels of government and funding mechanisms.

Developing plans to adapt and respond

Infrastructure owners and those in the broader built environment sector should, however, take some comfort that these issues are now well and truly on the radar. The release of the NCCRA provides a very useful starting point to enable them to begin to understand their own risks and develop plans to adapt and respond to these.

It is important that infrastructure owners take a strategic approach to planning for climate risk and embed climate change considerations into the way they do business. This is summarised in Figure 1 and includes planning (assessing and understanding risks and vulnerabilities), acting and observing or adjusting as required due to the future uncertainty with climate projections.

Figure 1: A strategic approach to climate adaptation.

Figure 2 presents a useful range of high-level principles that should be considered when responding to and managing climate risks. These cover decision making and long-term thinking, collaboration, stewardship and kaitiakitanga and prioritising actions with multiple benefits.

Key focus for those involved in the built environment

Climate change risk and adaptation must become a central consideration for all actors within the built environment. Importantly, this is in addition to the urgent need to reduce emissions.

The NCCRA has shed light on key risks for New Zealand and provides a useful framework and head start for regions and sectors to understand and begin to manage risks relevant to their interests. This, along with the Zero Carbon Act reporting power and the proposed mandatory climate-related financial disclosure scheme, provides added incentive for councils and infrastructure utilities to respond and ensure that they are contributing to a resilient future for their communities.

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For more

To read National climate change risk assessment for New Zealand, visit www.mfe.govt.nz.

Download the PDF

More articles about these topics

Articles are correct at the time of publication but may have since become outdated.

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Figure 1: A strategic approach to climate adaptation.

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