Adaptation: building climate resilience

Last updated: 21 December 2023

MBIEs Building for Climate Change programme (BfCC) is working on improving the climate resilience of buildings.

Climate change is increasing the frequency of severe weather events in Aotearoa/New Zealand. It is also driving slow-onset changes like drought, sea-level rise and altered rainfall patterns.

Considering current and future climate hazards there may be some areas that are unsuitable for building. In other areas, the risk of damage to existing buildings may increase and decisions need to be made on whether to retrofit buildings to improve their ability to withstand climate impacts or to accept the risk and prepare to repair buildings damaged by severe weather events.

National Adaptation Plan

Aotearoa/New Zealand's first National Adaptation Plan (NAP) was released in August 2022. It sets out strategies, policies and proposals that the government will undertake through to 2028. It provides the government’s response to the risks identified in the National Climate Change Risk Assessment 2020.

NAP actions and responsibilities

MBIE's Building for Climate Change programme co-led the development of Chapter 7, Homes, Buildings and Places of the NAP, alongside Te Tūāpapa Kura Kāinga - Ministry of Housing and Urban Development, and Ministry for the Environment – Manatū Mō Te Taiao.

There are four NAP actions that MBIE (Building performance) are responsible for:

Action 3.25: Design methodology for risk assessments of public buildings (2024-2026)

This action is to help owners of public buildings assess and understand climate risks and implement adaptation strategies.
Action 5.7: Reduce and manage the impacts of climate hazards on homes and buildings (2022-2026)

The research promoted by this action will inform regulatory and other changes needed to enable adaptation to climate hazards.
Action 7.4: Update regulatory requirements to ensure buildings are designed, and constructed to withstand more extreme climate hazards (2024-2028)

This action will improve the quality of buildings and make them more resilient to future climate impacts.
Action 7.6: Manage potential impacts of adaptation related to regulatory change (2026-2028)

This action will address negative impacts of regulatory changes for buildings and manage barriers to climate adaptation for the building sector.

MBIE will be work closely with the building sector to deliver on their actions in the NAP.

Climate adaptation

Climate adaptation is the process by which behaviours, systems and ways of life are adjusted to the existing and future impacts of climate change.

For the built environment, this means that buildings are designed, built, and used in a way that is suitable for the current climate as well as a more extreme future climate.

Climate resilient buildings

Building climate resilient buildings means building the right buildings in the right places. This means ensuring that buildings:

can withstand projected climate hazards that the building is likely to be exposed to over its lifetime, and
are built in areas where exposure to climate hazards is minimal or adequately managed.

Climate resilient building design

Resilient building design is the practice of designing buildings that can withstand and quickly recover from the effects of climate change, such as extreme weather, sea-level rise and flooding.

In Aotearoa/New Zealand, buildings need to be designed to withstand the effects of earthquakes, such as ground shaking and liquefaction, and also for different current climate zones and wind strengths, depending on the region. Future weather and climate related resilience is another aspect that will need to be considered in future.

Building the future

Resilience for buildings involves more than robust construction. Buildings need to be designed to be more climate friendly so they can reduce the impact they have on the environment.

Through thoughtful design and considering their lifecycle impact, it is possible to build low-carbon climate-resilient homes and buildings that use materials efficiently, are more durable and resilient to the effects of climate change.

When buildings are more durable and long lasting, the need for costly repairs and maintenance over time is reduced which could result in less cost over time as well as reducing emissions that would result from the building work needed to repair or replace them.

To ensure people can use their homes and buildings for longer, good design can enable future flexibility. Consideration should be given to ways of re-purposing and re-using buildings, rather than demolishing them.

Climate hazards and risks

Climate risks and climate hazards have an influence on the climate adaptation strategy for buildings.

The Building for Climate Change programme will focus on how buildings are designed and constructed to withstand, or be less vulnerable to, the effects of climate hazards.

Other risks that are related to where buildings are located and decisions and rules for how land can be used are made by councils through their district plans. These plans are developed under the resource management system, which promotes sustainable management of natural and physical resources.

Climate risk

A climate risk is the potential that a climate hazard may cause adverse consequences.

Climate risk is the interaction of climate hazard, exposure, and vulnerability.

For example: A house is built close to the sea.

The hazard = rising sea level caused by climate change
The exposure = the house is next to the shore, so its exposure is high
Vulnerability = The house may be vulnerable if it is not built to withstand the rising sea.

Climate hazards

A climate hazard is an event or trend that may result in the loss or damage to homes and buildings and injury or loss of life or other health impacts to people who occupy them.

The following are climate hazards that are likely to impact buildings:

Floods

Aotearoa/New Zealand's major urban centres and much of our population are located on the coast, on floodplains, or near major rivers. Homes, buildings and communities in these areas are at risk of flooding as a result of more frequent or heavier rain, storm surges and sea-level rise.

The number of people exposed to these hazards is already high and will increase as high intensity rainfall events become more frequent and intense due to climate change. As the sea level continues to rise, areas of low-lying coastal land that currently flood during storms or king tides will experience more frequent and severe inundation.

MBIE has published a guidance document on the natural hazard provisions of the Building Act. This is intended for Building Consent Authorities but may also be useful for building owners and their designers who are building on land that is at risk of flooding.

MBIE has also published guidance to homeowners and occupiers of buildings who have been affected by the severe weather events. This information may also be useful to the owners of any property that has been affected by flooding.

Slope stability quick guide [PDF 4MB]

Flooding resources

Unstable slopes and slips

A severe weather event can involve a combination of different natural hazards. Heavy or persistent rainfall can cause slopes to become unstable and result in landslides.

MBIE has published a slope stability guide to provide direction to homeowners and occupiers of buildings that were affected by the extreme weather events of spring 2023, however this guide is useful to anyone whose land or building has been damaged by slips or slope instability.

Slope stability quick guide [PDF 4MB]

Severe wind

Extreme winds may cause damage to, or the destruction of buildings. Buildings need to be designed for the wind zone, speed and loading for the area where the building is to be located.

A way determining the wind zone for a specific location is in NZS 3604:2011 Table 5.1.

BRANZ has also published a digital map so that you can find out what zone your property is in, and a guide on how to find the correct wind zone for a site using NZS 3604:2011.

Digital map (BRANZ) - experience.arcgis.com

Design Right - Wind zones and NZS 3604 [PDF 1.3MB] - buildmagazine.org.nz

For existing houses, it is not a requirement to strengthen or upgrade to comply with current Building Code requirements for structural stability, however vulnerable building elements, such as roofs, should be secured to stop them being blown away in an extreme wind event.

Wildfires

On average, there are 3,000 to 4,000 wildfires in Aotearoa/New Zealand each year. Wildfires can lead to the loss of life and property. Smoke from wildfires can impact human health through reduced air quality.

Higher temperatures, stronger winds, and periods of drought means that the fire risk in parts of Aotearoa/New Zealand will increase.

Understanding the risk is the first step to protecting homes and buildings from wildfire damage. Fire Emergency New Zealand (FENZ) has information on their website.

Protect your home from outdoor fires - fireandemergency.nz

Heat and overheating

Rising average temperatures may result in reduced heating demand, but an increase in cooling and air conditioning demand. Extreme heat can also reduce the durability of building materials, especially plastics and coatings.

A detailed site analysis at the earliest stages of a building project will help you identify the optimum positioning and orientation of the building on the site and identify passive cooling opportunities such as shading from existing and new landscaped areas.

Aotearoa/New Zealand's buildings are usually of lightweight construction, so the use of thermal mass for controlling overheating may not be effective. Instead, a combination of insulation, shading, and ventilation can be used to create a comfortable internal environment without increasing emissions by relying solely on mechanical air-conditioning for cooling.