Global Warming Effects Around the World

Tasman Glacier, New Zealand

Top Impact

Freshwater (Land ice)

Other Impacts

People (Water use)

People (Costs)

Tasman glacier—a tourist showpiece and storehouse for water resources in New Zealand's Southern Alps—is shrinking fast because of global warming. Scientists expect the glacier to continue to dwindle, and eventually to disappear. This aerial photo shows its dark, rock-covered surface alongside a lake recently formed by meltwater, with chunks of broken-off glacial ice floating on the lake's surface.1

Key Facts

Global warming is melting the glaciers of New Zealand's Southern Alps, potentially damaging local tourism, water resources, and biodiversity.4

  • Tasman glacier—New Zealand's largest and longest—is shrinking so rapidly that its meltwater formed a new lake toward the end of the twentieth century.3,5
  • New Zealand is projected to warm by 1.8° F (1° C) by mid-century, and 3.6° F (2° C) by late this century, according to best estimates.12,13
  • Scientists expect New Zealand's glaciers to shrink noticeably even given small increases in temperature, and warn that the Tasman glacier is likely to eventually disappear.4,11,16,5


Glacial ice meets temperate rainforest in the Southern Alps, a mountain range on New Zealand's South Island.2 Glaciers in the Southern Alps are at the heart of several national parks.3 These glaciers are melting as the world's climate warms, potentially damaging local tourism, water resources, and biodiversity.4

About 18 miles (29 kilometers) long and up to 2,000 feet (600 meters) thick, Tasman glacier in Aoraki/Mount Cook National Park is New Zealand's largest and longest glacier.3 Tasman is melting so rapidly—at an average rate of 590 feet (180 meters) per year since the 1990s—that a lake formed at the end of the glacier in the late twentieth century.3,5 By 2008 the lake was more than four miles (seven kilometers) long, 1.2 miles (two kilometers) wide, and 800 feet (245 meters) deep.5

Ice on land accounts for 75 percent of the world's freshwater, and covers 10 percent of Earth's surface.6 All but 3-4 percent of this ice is tied up in the ice sheets of Greenland and Antarctica. Of the remainder, 50 percent is in North America, 44 percent in Eurasia, 5 percent in South America, and 1 percent in New Zealand.7

By storing water as ice, Earth's glaciers are a small but significant water resource.7 They provide a source of water during droughts and in the summer, after seasonal snows have melted. The water can be used to produce hydroelectric power and provide irrigation.3

Glaciers around the world have been retreating over the past century. The rate of retreat has increased in the past decade, and the total volume of glaciers on Earth is rapidly declining.6,8,9

In New Zealand and Australia, the volume of glacial ice decreased by nearly one-half over the past century, and at least one-quarter of glacier mass has been lost since 1950.4,7,10 Glaciers in the Southern Alps advanced in the 1990s—perhaps because of rising precipitation—but they have been shrinking since 2000.6 Studies show that temperature is the dominant factor influencing the length of maritime glaciers such as Franz Josef glacier.11

What the Future Holds

New Zealand is projected to warm 1.8° F (1° C) by mid-century, and 3.6° F (2° C) by late this century, according to best estimates.12,13 Scientists expect winters to be shorter and summers hotter. The South Island could have 10 to 30 fewer frost days, and 5-70 more days with temperatures topping 86° F (30° C), by 2100.4,14

Tasman and other New Zealand glaciers are expected to continue shrinking noticeably even with small increases in temperature as our climate changes, although that effect may be delayed in the southwest, where winter and spring precipitation could increase seasonal snow and ice accumulation.15 New Zealand's glaciers are projected to shrink noticeably.4,11,16

Scientists warn that Tasman glacier is likely to retreat at an average annual rate of 1,500-2,700 feet (477-822 meters), and risks eventually disappearing.5 Rapid melting of the glacier has already sent chunks of ice into the lake, and is likely to cause major—possibly catastrophic—avalanches of rock and debris.17

Glacial melting is likely to reduce tourism in towns such as Fox and Franz Josef, and national parks such as Aoraki/Mount Cook.4 A loss of biodiversity is also expected: 200 to 300 indigenous plant species may disappear in New Zealand alone.4,18

Other potential impacts of glacial melting include greater risk of avalanches and flooding,4 reduced hydropower capacity during dry seasons, and a decline in the amount of water available for irrigation.



  1. Photograph used by permission. Lestari Handoyo.
  2. New Zealand Tourism Board. 2010. Southern Alps. Online at travel/ about-nz/ features/ southern-alps-feature/ southern-alps.cfm. Accessed May 2, 2010.
  3. Ministry of Culture and Heritage. 2010. Glaciers and glaciation. In: Te Ara: The encyclopedia of New Zealand. Wellington, New Zealand. Online at en/ glaciers-and-glaciation. Accessed May 3, 2010.
  4. Hennessy, K., B. Fitzharris, B.C. Bates, N. Harvey, S.M. Howden, L. Hughes, J. Salinger, and R. Warrick. 2007. Australia and New Zealand. In: Climate change 2007: Impacts, adaptation and vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Edited by M.L. Parry, O.F. Canziani, J.P. Palutikof, P.J. van der Linden, and C.E. Hanson. Cambridge University Press, pp. 507-540.
  5. Massey University. 2008. Tasman glacier retreat extreme. Albany, New Zealand. Online at massey/ about-massey/ news/ article.cfm?mnarticle=tasman- glacier-retreat-extreme-23-04-2008. Accessed May 3, 2010.
  6. Lemke, P., J. Ren, R.B. Alley, I. Allison, J. Carrasco, G. Flato, Y. Fujii, G. Kaser, P. Mote, R.H. Thomas, and T. Zhang. 2007. Observations: Changes in snow, ice and frozen ground. In: Climate change 2007: The physical basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Edited by Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor, and H.L. Miller. Cambridge University Press, pp. 337-383.
  7. Chinn, T.J. 2001. Distribution of the glacial water resources of New Zealand. Journal of Hydrology (NZ) 40:139-187.
  8. U.S. Global Change Research Program. 2009. Global climate change impacts in the United States. Edited by T.R. Karl, J.M. Melillo, and T.C. Peterson. Cambridge University Press.
  9. Steffen, K., P.U. Clark, J.G. Cogley, D. Holland, S. Marshall, E. Rignot, and R. Thomas. 2008. Rapid changes in glaciers and ice sheets and their impacts on sea level. In: Abrupt climate change. Synthesis and assessment product 3.4. Reston, VA: U.S. Geological Survey.
  10. Clare, G.R., B.B. Fitzharris, T.J. Chinn, and M.J. Salinger. 2002. Interannual variation in end-of-summer snow-lines of the Southern Alps of New Zealand, in response to changes in Southern Hemisphere atmospheric circulation and sea surface temperature patterns. International Journal of Climatology 22:107-120.
  11. Anderson, B., and A. Mackintosh. 2006. Temperature change is the major driver of late-glacial and Holocene glacier fluctuations in New Zealand. Geology 34:121-124.
  12. New Zealand Climate Change Office. 2008. Climate change effects and impacts assessment: A guidance manual for local government in New Zealand, executive summary. Wellington: Ministry for the Environment. Online at publications/ climate/ climate-change-effect-impacts- assessments-may08/page1.html. Accessed May 3, 2010.
  13. "Best estimates" are the average results of all the model runs for the low-emissions and high-emissions scenarios of the Intergovernmental Panel on Climate Change.
  14. Mullan, A.B., M.J. Salinger, C.S. Thompson, and A.S. Porteous. 2001. The New Zealand climate: Present and future. In: The effects of climate change and variation in New Zealand: An assessment using the CLIMPACTS system. Edited by R.A.Warrick, G.J. Kenny, and J.J. Harman. Hamilton: International Global Change Institute, University ofWaikato, pp. 11-31. Online at igci/ climpacts/ Linked%20documents/ Chapter_2.pdf.
  15. New Zealand Climate Change Office. 2008. Climate change effects and impacts assessment: A guidance manual for local government in New Zealand, Table 2.1: Main features of New Zealand climate change projections for 2040 and 2090. Wellington: Ministry for the Environment. Online at publications/ climate/ climate-change-effect-impacts-assessments-may08/ table-2-1.html. Accessed May 3, 2010.
  16. Anderson, B. 2004. The response of Ko Roimate o Hine Hukatere Franz Josef glacier to climate change. PhD thesis. Christchurch: University of Canterbury.
  17. Kirkbride, M.P., and C.R. Warren. 1999. Tasman glacier, New Zealand: Twentieth-century thinning and predicted calving retreat. Global and Planetary Change 22:11-28.
  18. Halloy, S.R.P., and A.F. Mark. 2003. Climate change effects on alpine plant biodiversity: A New Zealand perspective on quantifying the threat. Arctic Antarctic Alpine Research 35:248-254.
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