Climate change impacts in New Zealand

This page outlines likely climate change impacts in New Zealand. It links to information that local government can use to prepare its response to climate change. 

What climate change impacts are likely in New Zealand?

In New Zealand likely climate change impacts include:

  • higher temperatures, more in the North Island than the South, (but still likely to be less than the global average)
  • rising sea levels
  • more frequent extreme weather events such as droughts (especially in the east of New Zealand) and floods
  • a change in rainfall patterns - higher rainfall in the west and less in the east.

Summary of climate change impacts

Issue

Main points

Higher temperatures

  • There is likely to be an increase in demand for air-conditioning systems and therefore for electricity in summer
  • Conversely, there will be a reduction in demand for winter heating meaning less costs for bill payers and reducing stress on those who cannot afford electricity

Flooding

  • More frequent intense winter rainfalls are expected to increase the likelihood of flooding by rivers, as well as flash flooding when urban drainage systems become overwhelmed

Water resources

  • Water demand will be heightened during hot, dry summers
  • Longer summers with higher temperatures and lower rainfall will reduce soil moisture and groundwater supplies
  • River flows are likely to be lower in summer and higher in winter
  • Lower river flows in summer will raise water temperatures and aggravate water quality problems

Health

  • Higher levels of mortality related to summer heat are expected
  • Higher winter temperatures would be likely to lead to a reduction in winter related mortality and illnesses such as colds and flu

Biodiversity

  • Warmer weather would favour conditions for increased competition from exotic species as well as the spread of disease and pests, affecting both fauna and flora
  • Warmer temperatures will reduce some critical habitats, increasing the risk of localised extinction
  • Increased summer drought will cause stress to dry lowland forests
  • Earlier springs and longer frost-free seasons could affect the timing of bird egg-laying, as well as the emergence, first flowering and health of leafing or flowering plants

Built environment

  • Increased temperatures may reduce comfort of occupants in domestic, commercial and public buildings, and could lead to business disruption

Transport

  • Hotter summers may damage elements of transport infrastructure, causing buckled railway lines and rutted roads, with associated disruption and repair costs

Business and Finance

  • Households may find it more difficult to access adequate insurance cover in the face of increased flood risk
  • Fruit and vegetable growers may find it more expensive to insure against weather related damage eg, hail
  • The risk management of potential climate change impacts may provide significant opportunities for business

Positive and negative impacts for New Zealand

These changes will result in both positive and negative effects.

For example:

  • agricultural productivity is expected to increase in some areas but there is the risk of drought and spreading of pests and diseases. It is likely that there would be costs associated with changing land-use activities to suit a new climate
  • people are likely to enjoy the benefits of warmer winters with fewer frosts, but hotter summers will bring increased risks of heat stress and subtropical diseases
  • forests and vegetation may grow faster, but native ecosystems could be invaded by exotic species
  • drier conditions in some areas are likely to be coupled with the risk of more frequent extreme events such as floods, droughts and storms
  • rising sea levels will increase the risk of erosion and saltwater intrusion, increasing the need for coastal protection
  • snowlines and glaciers are expected to retreat and change water flows in major South Island rivers.

Planning for climate change

The Ministry for the Environment provides local government with detailed scientific, technical and policy guidance as well as case studies on how to plan for the potential impacts of climate change.

Reviewed:
01/07/14