Providing climate change advice for New Zealand

Regional-scale climate projections assist local authorities to assess risks presented by climate change now and prepare their communities for the future impacts.

National-scale climate change projections 

Following the release of the Fifth Assessment Report by the Intergovernmental Panel on Climate Change (IPCC), in 2016 NIWA developed national-scale climate change projections for the Ministry for the Environment. These projections were updated in 2018 with the addition of results from a report on very extreme rainfall (the HIRDS report; Carey-Smith et al., 2018).

You can download these national-scale projections from the Ministry for the Environment’s website.

The following report distils and interprets information relevant to Aotearoa New Zealand from the Working Group 1 contribution to the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report titled ‘The Physical Science Basis’, published in August 2021:

Aotearoa New Zealand climate change projections guidance: Interpreting the latest IPCC WG1 report findings

Regional variation in climate change impacts across New Zealand

The impacts of climate change will vary across different parts of New Zealand. For example, the west coast of the South Island is projected to experience more rainfall than at present, while the east of the South Island is projected to experience reductions in rainfall. Similar variations are expected for other aspects of climate – such as average temperatures, hot days, frost days, humidity and wind.For this reason, regional-scale climate change projections can be more useful for New Zealand's local and regional councils. Regional-scale projections can help with assessing local risks from a changing climate and preparing communities for future impacts. 

Regional-scale climate change projections

NIWA has provided regional-scale high resolution (5 km x 5 km) maps and detailed reports to a number of New Zealand local government bodies (regional, district, and city councils).

These maps show projections for a large range of climate variables at 2040 and 2090 and for two different climate change scenarios (based on the trajectory of greenhouse gas concentrations in the future).

Along with descriptions of the projected future changes to different climate variables, these reports have been tailored to each region following discussions about sectors of concern. These may include impacts of climate change on aspects including biodiversity, biosecurity, river flows, aquaculture, agriculture, storm surges and groundwater, among others. Climate variables that were mapped include temperature, precipitation, wind, humidity, soil moisture, and solar radiation. Indices and threshold information has also been produced (e.g. changes to the numbers of ‘hot days’ or days above 25 degrees per year). GIS layers of the climate projections have also been provided so that the councils may use them in their planning and decision making processes.

Find out more

You can read more about climate change scenarios under the IPCC’s Fifth Assessment Report and NIWA’s work in developing national-scale climate change projections

Links to NIWA reports for local government (listed alphabetically)

Auckland Council

Auckland region climate change projections and impacts | Auckland Council

Bay of Plenty Regional Council

Climate Change projections for the Bay of Plenty - summary of the NIWA report Oct 2019

Environment Canterbury

Environment Southland, Gore District Council, Invercargill City Council, and Southland District Council

Greater Wellington Regional Council

Climate Change and the Greater Wellington Region - a new report

Gisborne District Council and Hawke's Bay Regional Council

Horizons Regional Council

Kaipara District Council

Marlborough District Council

Northland Regional Council

Otago Regional Council

Taranaki Regional Council

Tasman District Council

Waimakariri District Council