New Zealand Temperate Glaciers
March 31, 2015
Currently, the topmost agenda of practically all governing bodies across the globe is climate change. Internationally coordinated glacier observations across the seven continents are a clear indication of the impact of global warming and a measure of its momentum. Over the past four and a half decades, a third of the New Zealand temperate glaciers has shrunk, negatively impacting the vast multimillion dollar glacier tourism economic of New Zealand. Furthermore, this glaciation has completely changing the biodiversity of this region through the formation of lakes and cirques.
Keywords: Glaciation, New Zealand temperate glaciers, ablation.
The Human Development Report released by the United Nations Development Program (UNDP) in 2007/2008 outlined the impact of global warming noting that Glaciers are a critical component of the earth’s system and the current accelerated melting and retreat of glaciers has had a severe impact on not only the environment but also the human well-being globally. Of the eight Millennium Development Goals, Ensuring Environmental Sustainability was and still is the most critical and the challenging with recent changes in vegetation patterns, water and energy supply, natural disasters such as floods and storms, and economic livelihoods are all linked to one of the most critical component of the earth’s system: Glaciers. Glaciers contain a variety of proxies for climate coercing and as a result, they have been globally recognized as a valuable element in early detection for climate change, Morgenstern (2014).
New Zealand temperate glaciers have over the years provided vital information for studying environmental change due to their isolated position in the South Pacific Ocean. The 3144 inventoried New Zealand temperate glaciers are located in the Southern Alps of New Zealand covering 1158 square kilometers. The strategic positioning of the Southern Alps creates a steep eastward precipitation gradient within the humid maritime climate and as a result, the strong fohn effects in these westerly conditions rapidly and evenly increases precipitation from 3,000 mm along the coastal plain to a high of over 10,000 mm in the areas immediately west of the Main Divide, Chin et al (2005).
New Zealand Temperate Glaciers are made up on numerous cirque and alpine glaciers which travel up well above the regional snowline. The central Southern Alps contain large debris-mantled glaciers valleys which are well-known for their far-reaching areas of supraglacial debris cover on the lower tongues. This is mainly because the New Zealand Temperate glaciers lie within the humid-maritime climates where the equilibrium line is at a relatively low altitude. Consequently, ablation takes place regularly and at a relatively rapid flow due to the warm temperatures and long snow-melting seasons. Furthermore, the recent changes in global climate has enhanced melting and runoff causing high mass turnovers in the valleys, Union of Concerned Scientists (2011).
The response of a glacier to climate change involves changes in atmospheric conditions such as air temperature, solar radiation, wind and cloudiness and precipitation which in turn influence the mass and energy symmetry of the entire glacier surface. According to United Nations Environmental Program (UNEP), over the last four and a half decades, a third of the Zealand’s Southern Alps’ ice volume has now disappeared. All the 127 glaciers surveyed in this region have shrunk by 38% and lost nearly 25% of their area of coverage since the mid-1850s. However, the survey also revealed that the retreat of the glacier tongues has advanced in recent decades providing a clear signal of increased climate change over this period, Zemp, & Woerden (2008).
Figure 1: Southern Alps ice volume, NIWA (2014).
This dynamic reaction has not only led to the drawback of the glacial tongues within the Alpines but it has caused significant damage to the local tourism, water resources and overall biodiversity. For example, the rapid melting of the Tasman glacier in the Mount Cook National Park has caused a lake more than seven kilometers long, two kilometers wide and 245 meters deep to be formed at the end of the glacier. Furthermore, the melt-water percolations has led to surface morphology changes and adversely affected tourism by resulting in increasingly problematic access for guided walks on the Franz Josef Glacier. The steepening of ice slopes and the increase in debris cover within this region has made it more hazardous for tourism activities to be carried out. Moreover, the combined run-off of these glaciers has made the region unfamiliar and the alpine scenery less impressive to tourists, Zemp & Haeberli (2014).
Nonetheless, the ablation action of these glaciers in the Southern Alpines has led to the formation of magnificent landforms such as the cirques. As an active agent of erosion, glaciers gradually wear away the earth’s surfaces carving out “u-shaped” ridges within the valleys in a process known as glaciation. Other than the lake, this is a clear indication that glaciation is positively and negatively manifested in the Southern Alpine region in New Zealand; positively through the formation of the lake and negatively through its adverse effect on glacier tourism.
Chinn, T., Winkler, S., Salinger, M., & Haakensen, N. (2005). Recent Glacier Advances In Norway And New Zealand: A Comparison Of Their Glaciological And Meteorological Causes. Geografiska Annaler, Series A: Physical Geography, 85(A), 141-157.
Morgenstern, U. (2014). Dating of Southern Alps Glacier Ice, Mount Cook National Park, New Zealand. Lower Hutt: Institute of Geological and Nuclear Sciences Limited.
Union of Concerned Scientists (2011). Tasman Glacier, New Zealand, Expected to Disappear | Global Warming Effects. (n.d.). Retrieved March 31, 2015.
Zemp, M., & Woerden, J. (2008). Global glacier changes: Facts and figures. Nairobi, Kenya: United Nations Environment Programme ;.
Zemp, M., & Haeberli, W. (2014). Glaciers and Ice caps (Vol. 6B). Zurich: UNEP.