Adapted by Ministry for the Environment and Statistics New Zealand to provide for environmental reporting transparency. Dataset used to develop the "Annual glacier ice volumes" indicator (available at https://www.stats.govt.nz/indicators/annual-glacier-ice-volumes).
This dataset measures the total volume of ice in glaciers greater than one hectare in area throughout New Zealand between 1978 and 2020.
Glaciers are iconic indicators of climate change (Mackintosh et al., 2017). Glacier fluctuations are amongst the clearest signals of climate change because glaciers are highly sensitive indicators of the earth’s surface energy balance (Chinn, 1996). The amount of loss seen in two recent extreme mass-loss events for New Zealand glaciers was more likely to have occurred due to anthropogenic climate change (Vargo et al., 2020).
Glaciers provide an important natural resource that supports power generation, primary production, and water resources. Glaciers act as a reservoir of water and are vital for plants and animals dependent on downstream rivers and lakes, particularly throughout drier seasons. Glaciers regulate downstream water temperature, which is important for many aquatic species, including Taonga species. Changes to ice storage and melting can affect ecological and hydropower resources downstream, as well as important cultural values and tourism. Melting glaciers also add to coastal sea level rise, further contributing to the impacts of climate change.
Climate change is causing summer snowlines to rise and glaciers to retreat. A recent survey of all glacier ice in New Zealand found that the North Island glaciers had declined in area by 25 percent since 1988. For glaciers situated close to the limits of where they can exist, like those on Mt Ruapehu (the only North Island glacierised site today), even moderate warming scenarios predicted for the coming decades may lead to their extinction (Eaves & Brook, 2020). Mt Ruapehu is in the Tongariro National Park, which has been awarded UNESCO World Heritage status for its cultural and natural values. Ruapehu’s glaciers serve as a cultural reference point for local iwi. For example, the Whangaehu River, which has been recognised as indivisible and a living being, emerges from the Whangaehu Glacier on the east flank of Mt Ruapehu. The loss of glaciers will have a negative impact on culture and historical kōrero.
Between 1978 and 2020 the total volume of glacial ice in New Zealand decreased by 35 percent and the rate of annual loss increased.
The total volume of ice in glaciers in New Zealand decreased from 53.3km3 in 1978 to 34.6km3 in 2020.
The highest annual ice loss occurred in 2018 with 2.7km3 lost. The second highest annual ice loss occurred in both 2019 and 2011, with 2.5km3 lost.
More information on this dataset and how it relates to our environmental reporting indicators and topics can be found in the attached data quality pdf. Summary report available at https://environment.govt.nz/publications/environment-aotearoa-2022/.
References
Chinn, T. J. (1996). New Zealand glacier responses to climate change of the past century. New Zealand Journal of Geology and Geophysics, 39(3), 415–428. ++https://doi.org/10.1080/00288306.1996.9514723++
Eaves, S. R., & Brook, M. S. (2020). Glaciers and glaciation of North Island, New Zealand. New Zealand Journal of Geology and Geophysics, 64(1), 1–20. ++https://doi.org/10.1080/00288306.2020.1811354++
Mackintosh, A. N., Anderson, B. M., Lorrey, A. M., Renwick, J. A., Frei, P., & Dean, S. M. (2017). Regional cooling caused recent New Zealand glacier advances in a period of global warming. Nature Communications, 8(1). ++https://doi.org/10.1038/ncomms14202++
Vargo, L. J., Anderson, B. M., Dadić, R., Horgan, H. J., Mackintosh, A. N., King, A. D., & Lorrey, A. M. (2020). Anthropogenic warming forces extreme annual glacier mass loss. Nature Climate Change, 10(9), 856–861. ++https://doi.org/10.1038/s41558-020-0849-2++
