Change in glacier ice volume

  • Image, change in glacier volume.

    Archived 19 October 2017

    A glacier is a body of slow-moving ice, at least 1 hectare in area that has persisted for two decades or longer. Glacier volume is strongly influenced by climate factors, such as temperature and precipitation. Changes in glacier ice volumes give some indication of changing climate conditions in New Zealand.

    We classified Change in glacier ice volume as supporting information.

    Key findings

    From 1978 to 2014:

    • the trend in glacier ice volumes showed a statistically significant decrease
    • 19.0km3 of glacier ice was lost (a 36 percent decrease in volume, from 53.3km3 in 1978 to 34.3km3 in 2014).

    • The maximum ice volume occurred in 1997 (53.9km3).
    • The minimum ice volume occurred in 2012 (34.2km3).

    Definition and methodology

    To measure the volume of glacier ice we use cubic kilometre (km3) water-equivalent volumes.

    NIWA uses measurements of the annual end-of-summer snowline for 49 glaciers to estimate glacier ice volumes. This is based on photographs taken during aerial surveys. Adverse weather means not all glaciers can be measured each year. It can also be difficult to identify the end-of-summer snowline, for example, when a recent snowfall obscures the snowline, or cloud cover or backlighting makes it difficult to see.

    Data quality

    We classified Change in glacier ice volume as supporting information.

    Relevance

     This supporting information is a partial measure of the ‘Rain, hail, sleet, and snow’ topic.

    Accuracy

     The accuracy of the data source is of high quality.

    See Data quality information for more detail.

     

    Published 21 October 2015

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