Temperature: our changing climate

This section describes changes in New Zealand’s temperatures over time, and describes possible impacts on health. 

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Increasing annual temperatures in New Zealand
Warm days more common in northern and eastern New Zealand
A warmer climate will affect our health

Increasing annual temperatures in New Zealand

In New Zealand, NIWA has concluded that the mean annual temperature increased by 0.96°C between 1910 and 2010 (Figure 1).

Figure 1: Mean annual temperature in New Zealand has risen by 0.96°C over the past 100 years WaterSupplySystem

Source: NIWA [1]

Warm days more common in northern and eastern New Zealand

In environmental health monitoring, temperature extremes are used in preference to mean temperatures, because they correlate more with health effects (see below).   

We used NIWA weather data from around the country to determine which areas have high numbers of very cold and very warm days. 

Warm days are more common in several isolated territorial authorities, particularly in the north and east of both main islands (movie 1). 

Movie 1: Days over 25°C 2000-2013 by territorial authority, New Zealand

More cold days are experienced in the south than the north (movie 2).  

Movie 2: Days under 0°C 2000-2013 by territorial authority, New Zealand

Download factsheet on pdficon small temperature, climate change and health

A warmer climate will affect our health

Temperature changes affect our health. 

Some temperature changes will benefit health.  A decrease in the number of very cold days will mean fewer cold-related deaths and hospitalisations from cardiorespiratory (heart and lung-related) conditions.

However, any reduction in cold-related health effects is likely to be outweighed by a projected increase in heat-related death and illness [2]. Heat can affect health in many ways, from a mild ‘heat rash’ to increasing death rates [3].

Temperature changes will affect vulnerable populations the most.  See more about vulnerable populations on the 'who is more at risk' webpage

Combining temperature data and population data shows us that Northland, the east coast of the North Island, and parts of the Bay of Plenty are likely to be regions where people are particularly affected by climate change.

Download factsheet on pdficon small vulnerable populations and climate change

Information about the data

For more information about the data and indicators, download the metadata datasheets below:

References

1. NIWA. 2010. 'Seven-station' series temperature data.   Retrieved May 7, 2014, from www.niwa.co.nz/our-science/climate/information-and-resources/nz-temp-record/seven-station-series-temperature-data

2. Smith K, Woodward A, Campbell-Lendrum D, Chadee D, Honda Y, Liu Q, et al. 2014. Human health: Impacts, adaptation and co-benefits. In C Field, V Barros, D Dokken, K Mach, M Mastrandrea, T Bilir, M Chatterjee, K Ebi, Y Estrada, R Genova, B Girma, E Kissel, A Levy, S MacCracken, P Mastrandrea and L White (Eds.), Climate Change 2014: Impacts, Adaptation, and Vulnerability. Part A: Global and Sectoral Aspects. Contribution of Working Group II to the Fifth Assessment Report of the Intergovernmental Panel of Climate Change. Cambridge, United Kingdom and New York, NY, USA: Cambridge University Press.

3. State of Victoria Department of Health. 2011. Heatwave plan for Victoria. Protecting health and reducing harm from heatwaves. Melbourne: Victorian Government.