Ice and Snow

The classic Arctic ice seal in a changing climate

Seal Ice Snow

Ringed seals are the classic Arctic seal in many regards, being found as far north as the Pole because of their ability to keep breathing holes open in ice that can reach 2 metres in depth. This species is certainly one of the most vulnerable of the high-Arctic seals to the declines in the extent or quality of sea ice because so many aspects of their life-history and distribution are tied to ice. Ringed seals also require sufficient snow cover on top of the ice to construct lairs for resting,...

The water towers of Asia

Hindu Kush Tian Sahn Himalaya

The Himalayas-Hindu Kush, Kunlun Shan, Pamir and Tien Shan While mountains traditionally have been considered the major water sources of the region, there is great diversity in the hydro-logical significance of mountains and glaciers for downstream mountain ranges (Figure 6B.10) function as water towers, providing water to people through much of Asia. The glacier-fed rivers originating from the mountain ranges surrounding the Tibetan Plateau comprise the largest river run-off from any single...

References

Climate Change 2007 The Physical Science Basis. Contribution of Working Group 1 to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change eds. S. Solomon, D. Qin, M. Manning, Z. Chen, M.C. Marquis, K. Averyt, M. Tignor and H.L. Miller . Intergovernmental Panel on Climate Change, Cambridge and New York 1 Thomas, D.N. 2004 . Frozen Oceans The floating world of pack ice. Natural History Museum, London 2 Gloersen, P., Parkinson, C.L., Cavalieri, D.J., Comiso,...

Projections of st century sealevel rise

The Intergovernmental Panel on Climate Change IPCC provides the most authoritative information on projected sea-level change. The IPCC Third Assessment Report TAR of 200123 projected a global averaged sea-level rise of between 20 and 70 cm the limits ofthe model projections between 1990 and 2100 using the full range of IPCC greenhouse gas scenarios and a range of climate models. When an additional uncertainty for land-ice changes was included, the full range of projected sea-level rise was 9 to...

Deadly ice avalanches of Glaciar in the Cordillera Blanca Peru

Avalanche Perou 1962

Many disasters have been recorded from the glaciers in the Cordillera Blanca. The 1962 and 1970 events originating from Glaciar 511 on the Nevados Huascaran142 Figure 6B.18 , the highest peak of which is at 6768 m above sea level in the Peruvian Andes, were particularly severe. On 10 January 1962, an ice avalanche took place with an estimated starting volume of 10 million m3 the avalanche travelled down 16 km and destroyed the city of Ranrahirca, where 4000 people died. On 31 May 1970, the most...

Ice algae the primary producers

Primary Producer Examples

Ice algae are the primary producers in ice-associated food webs, and consist primarily of diatoms, but also include other types of algae originating from the pelagic open-water system40,47. Large strands of the ice diatom Melosira arctica Figure 5.14 are found in Arctic multi-year ice48. The algae attach to ice-crystal structures on the underside of Arctic ice49, whereas in Antarctica, an important feature of the sea ice is the infiltration communities of algae, associated with the...

The snowloving deer of the Arctic

Reindeer and caribou (Rangifer tarandus) have been called chionophiles, snow loving. In fact, Arctic island subspecies of Rangifer are associated with a snow environment for up to ten months out of the year. Rangifer are the most dominant large mammal species in Arctic environments. The species has specialized adaptations in order to thrive in a cold environment. Their diet is energy rich winter lichen, which they obtain mostly by digging (cratering) under the snow70,71. Large hooves aid in...

Glacier responses to climatic changes

The response of a glacier to climatic change involves a complex chain of processes5,6. Changes in atmospheric conditions such as solar radiation, air temperature, pre cipitation, wind and cloudiness influence the mass and energy balance at the glacier surface7,8. Air temperature plays a predominant role, as it is related to the radiation balance and turbulent heat exchange, and it determines whether precipitation falls as snow or rain. Over time periods of years and decades, changes in energy...

Migratory sandpipers and snow on the Arctic tundra

Snow very much determines the distribution of Arctic birds. In the spring, 24-hour daylight and vast food supplies attract billions of waterbirds to migrate from virtually all corners ofthe world to breed in the Arctic. These migratory waterbirds need snow-free patches to feed and nest in the tundra. For sandpipers breeding in Greenland and Arctic Canada, such as the knot, dunlin and sanderling, both the density and timing of breeding have been shown to be strongly related to snow cover....

Tropical glaciers

Tropical glaciers are found in the high mountains of the Andes in Colombia (Figure 6B.19), Venezuela, Equador, Peru and Bolivia, as well as in the high mountains of East Africa (Figure 6B.20) and Irian Jaya, Indonesia. Around the period 1950-1990 they covered about 2760 km2 with about one quarter in the Peruvian Cordillera Blanca143 this area had shrunkto about 2500 km2 for the period 2000-2005144. The maximum extents of tropical glaciers occurred between the second half of the 17th century in...

Impacts on agriculture crops and animal husbandry

The dramatic impacts of snow cover on vegetation also apply to agricultural crops. Gradual changes in snow cover, as well as incidences of extreme snow events, can have a strong impact on crops both at the start and end of the growing season. Snow typically disappears in the spring before the start of the growing season. If it occurs during the growing season, snow can insulate crops from cold air or cause damage by freezing crops or breaking off branches and stems. An early autumn snow may...

Glaciers and water supply in Central Asia

On average, glacier melt contributes 10-20 per cent of the total river runoff in Central Asia39,120. During dry and hot years, the input of glacier water into summer river flow could be as high as 70-80 per cent, compared to 20-40 per cent in normal years. This proportion is critical for agriculture - the economic sector that consumes about 90 per cent of water resources and is highly dependent on water availability. During the severe droughts of 2000-2001 in the southern districts of Central...

The Caucasus icerock avalanche and its implications

One ofthe largest historical glacier disasters occurred in 2002 in the Russian Republic of North Ossetia in the Caucasus. An icerock avalanche resulting from a slope failure in the Kazbek region and a connected instability of the Kolka glacier devastated tens of kilometres along the length of the Genaldon valley13,45-47. The Kolka ice-rock avalanche Figure 6B.8 is remarkable for several reasons. The steep, high mountain wall ofthe initial slope failure was covered by firn and ice masses, a...

Impacts of seaice changes on culture and livelihoods of Arctic Indigenous Peoples

Environmental and seasonal cycles are an integral part of the human-environment system in Arctic regions, and the peoples of the north have a long tradition of adapting to shifting environmental conditions. However, the rapidity and pervasiveness of current and projected climate change pose new and unprecedented challenges to the adaptive capacity oflocal communities and Arctic societies31. Nearly four million people live in the Arctic today, including indigenous and non-indigenous people. Some...

Glacier changes and water availability in the tropical Andes

There is growing evidence that glacier retreat in the tropical Andes has accelerated in recent decades due to atmospheric warming134. Ongoing rapid glacier recession was found to have enhanced discharge at the expense of catchments storage138,139. The recent increase in runoff is not likely to last very long140. In the long run, changes in runoff may occur which could severely affect the availability ofwater resources forfuture generations, particularly during dry periods. Short-term increases...

Impacts on water resources

One of the most dramatic impacts of changing snow cover is on water resources. Snow cover in mountain regions provides critical water supplies, serving nearly one-sixth of the global population with freshwater for domestic, agricultural and industrial uses79. Much of the arid American West79 and Central Asia80 (Figure 4.10) depends heavily (about 75-85 per cent) on snow melt to supply water for municipalities and agriculture. Snow melt driven water resources are crucial for generation of...

Forces that drive the climate system

Atmospheric climate, represented primarily by temperatures, precipitation, and winds, undergoes externally-forced changes as well as natural, internal variations. External forcing factors include greenhouse gas fluctuations, dust from volcanic eruptions, and variations in the amount of solar radiation reaching the top of the atmosphere. These changes in atmospheric conditions influence the amount of ice and snow cover in a particular region and the regional climate is affected by them in turn....

The Late Glacial and Holocene the period since about years ago

At the time of the peak of the last ice age about 21 000 years ago, glaciers covered up to 30 per cent of the land2. Glacier fluctuations can be reconstructed back to that time using a variety of scientific methods. Understand- Figure 6B.4 Shrinking ofVernagtferner, Austria. This glacier in the European Alps lost almost 30 in area and more than 50 in mass between 1912 and 2003. Source Data and photos, taken by O. Gruber 1912 , H. Schatz 1938 , H. Rentsch 1968 and M. Siebers 2003 , provided by...