Mass balance reference glaciers in nine mountain ranges
Thirty reference glaciers with almost continuous
mass balance measurements since 1975
show an average annual mass loss of 0.58 m water
equivalent for the past decade (1996–2005), which is
more than twice the loss rate of the period 1986–1995
(0.25 m), and more than four times the rate of the
period 1976–1985 (0.14 m). The results from these
30 continuous mass balance series correspond well to
estimates based on a larger sample of more tha...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Trends in permafrost temperatures and active-layer thickness, Northern Tien Shan mountains
Mountain permafrost in Central Asia occupies approximately 3.5 million square kilometers and makes up about 15 per cent of the total permafrost area in the Northern Hemisphere. The climatic variations during the 20th century and especially during the last two decades have impacted current permafrost temperatures. In the Tien Shan Mountains, Qinghai-Tibet Plateau, and western Mongolian sector of the Altai Mountains, observations over the last 30 ...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
The Cryosphere, components and world maps
Snow and the various forms of ice - the cryosphere - play different roles within the climate system. The two continental ice sheets of Antarctica and Greenland actively influence the global climate over time scales of millennia to millions of years, but may also have more rapid effects on, for example, sea level. Snow and sea ice, with their large areas but relatively small volumes, are connected to key interactions and feedbacks at global scales...
01 Oct 2008 - by Hugo Ahlenius, UNEP/GRID-Arendal
Water towers of Asia - glaciers, water and population in the greater Himalayas-Hindu Kush-Tien Shan-Tibet region
The Himalayas–Hindu Kush, Kunlun Shan, Pamir and Tien Shan mountain ranges function as water towers, providing water to people through much of Asia. The glacier-fed rivers originating from the Himalaya mountain ranges surrounding the Tibetan Plateau comprise the largest river run-off from any single location in the world. While the mountains are homes to some 170 million people, the rivers that drain these mountains influence the lives of about 4...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Ice sheets, schematic illustration for Greenland and Antarctica
The ice cover in Greenland and Antarctica has two components – thick, grounded, inland ice that rests on a more or less solid bed, and thinner floating ice shelves and glacier tongues. An ice sheet is actually a giant glacier, and like most glaciers it is nourished by the continual accumulation of snow on its surface. As successive layers of snow build up, the layers beneath are gradually compressed into solid ice. Snow input is balanced by glaci...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Annual snowfall pattern for a typical mountain environment, Columbine Pass, Colorado 1971-2000
Mountain snow cover typically develops in the autumn and grows to a maximum depth in early spring. As day length and sun angles increase, so do air temperatures, causing snow cover to warm and begin to melt. Snow cover balances the availability of water in mountain environments. Where winter precipitation falls as rain, surface runoff occurs almost immediately. In contrast, snow stores water during the winter and then melts in the spring and ear...
01 Oct 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Mean snow-cover extent in the Northern Hemisphere 1966-2006
Snow occurs predominantly on the northern continents, on the sea ice of the Arctic Ocean and on Antarctica. On the Northern Hemisphere continents, snow covers a maximum mean area of 45.2 million km2, typically in January. The minimum snow-cover extent usually occurs in August and covers a mean area of 1.9 million km2, most of which is snow on the Greenland ice sheet and on mountain glaciers. As a result, snow cover is the surface characteristic r...
01 Oct 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Ratio of existing ski areas in the Alps with natural snow-reliability under current conditions and warmer conditions
Winter tourism is a significant part of the economy of Alpine countries and the most important source of income in many regions. In Austria, winter tourism revenue makes up 4.5 per cent of GNP and half of the total income from tourism. Much of winter tourism is based around the ski industry, which is dependent on reliable snow conditions. Although snow fall is expected to increase at high elevations, it is winter temperatures that largely determi...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Overview on glacier changes since the end of the Little Ice Age
Glaciers and ice caps reached their Holocene (the past 10 000 years) maximum extent in most mountain ranges throughout the world towards the end of the Little Ice Age, between the 17th and mid-19th century. Over the past hundred years a trend of dramatic shrinking is apparent over the entire globe, especially at lower elevations and latitudes. Within this general trend, strong glacier retreat is observed in the 1930s and 1940s, followed by static...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Glacier changes on Nevado de Santa Isabel, Colombia
With spectacular mountain peak glaciers melting away, the NEvado de Santa Isabel area in Colombia becomes less attractive to tourists. In addition, the local forestry and agricultural fertility suffer may suffer from reduced spring water. The retreat of glaciers is an indicator for changes in regional and global climate.
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
The Cryosphere, world map
Snow and the various forms of ice - the cryosphere - play different roles within the climate system. The two continental ice sheets of Antarctica and Greenland actively influence the global climate over time scales of millennia to millions of years, but may also have more rapid effects on, for example, sea level. Snow and sea ice, with their large areas but relatively small volumes, are connected to key interactions and feedbacks at global scales...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Mountain permafrost patterns and temperature gradients
Steep terrain and strong variability in surface temperatures are typical of mountain permafrost. The cross section in the foreground shows the complex distribution of subsurface temperatures characteristic of mountains, with the isotherms (lines linking points of equal temperature) nearly vertical in the ridge of the mountain. In the background, the colours on the mountain surface illustrate the strong variability in ground temperatures caused by...
01 Jun 2007 - by Stephan Gruber, University of Zürich. Hugo Ahlenius, UNEP/GRID-Arednal
Landcover - Europe and Central Asia
The Western part of the Eurasian continent, has some of the most populated and fertile parts of the World. Central Europe is densely populated, with few remaining fragments of undisturbed habitat, except for the mountain ranges. In the north - Scandinavia and Northern Russia, there is the taiga belt, with vast expanses of confierous forest, and further north, there is tundra and glaciers. Central Asia and Caucasus is a diverse region, with desert...
20 Jul 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Inland water and mountain systems
Inland water systems are permanent water bodies inland from the coastal zone and areas whose properties and use are dominated by the permanent, seasonal, or intermittent occurrence of flooded conditions. Inland waters include rivers, lakes, floodplains, reservoirs, wetlands, and inland saline systems.
30 Nov 2007 - by Philippe Rekacewicz, Emmanuelle Bournay, UNEP/GRID-Arendal
Pig farming in the Caucasus ecoregion
Over the recent number of years, as the economy came to a standstill, individual farms have replaced collective farming and subsistence agriculture and livestock breeding (cattle, sheep and goat) have became common. Along with the increase in farming, more and more land has been used as pasture land. Despite their low productivity, high Mountain areas are increasingly used as pasture grounds for sheep - leading to soil erosion and evoking avalanc...
29 Jan 2008 - by Manana Kurtubadze
Sheep and goats in the Caucasus ecoregion
Over the recent number of years, as the economy came to a standstill, individual farms have replaced collective farming and subsistence agriculture and livestock breeding (cattle, sheep and goat) have became common. Along with the increase in farming, more and more land has been used as pasture land. Despite their low productivity, high Mountain areas are increasingly used as pasture grounds for sheep - leading to soil erosion and evoking avalanc...
29 Jan 2008 - by Manana Kurtubadze
Climate zones of the Caucasus ecoregion
The Caucasus ecoregion covers an area of 580,000 km2, and includes six countries. The Greater Caucasus Mountain Range with its lofty peaks forms a formidable barrier between the northern and southern parts of the ecoregion. The Lesser Caucasus mountain chain extends across Georgia, Turkey, Armenia, Azerbaijan and into Iran. The climates in the regions mountaineous and temperature.
29 Jan 2008 - by WWF-Caucasus, design Manana Kurtubadze
The Caucasus ecoregion, topographic map
The Caucasus ecoregion covers a total area of 580,000 km2, includes six countries - Armenia, Azerbaijan, Georgia, Iran, Russian and Turkey - and follows the ecoregion definition prepared by WWF in their Action plan for Caucasus. The Greater Caucasus Mountain Range with its lofty peaks forms a formidable barrier between the northern and southern parts of the ecoregion. The Lesser Caucasus mountain chain extends across Georgia, Turkey, Armenia, Aze...
29 Jan 2008 - by Manana Kurtubadze, cartographer
Cattle in the Caucasus ecoregion
Over the recent number of years, as the economy came to a standstill, individual farms have replaced collective farming and subsistence agriculture and livestock breeding (cattle, sheep and goat) have became common. Along with the increase in farming, more and more land has been used as pasture land. Despite their low productivity, high Mountain areas are increasingly used as pasture grounds for sheep - leading to soil erosion and evoking avalanc...
29 Jan 2008 - by Manana Kurtubadze
Agricultural land in the Caucasus ecoregion
About 54% of a total of 44,019,400 ha of land is used for agriculture in the Caucasus. Most agricultural land is located in the plains, the Kuban-Azov plain, the Stavropol plateau, the Kura-Araks lowland and the Ararat valley while there is a shortage of farm land in mountain regions. The main crops of the Caucasus area are cereals, fodder, fruit, tea and tobacco.
29 Jan 2008 - by Manana Kurtubadze