Tag: Snow

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 red...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Formation of lakes and glacier lake outburst floods (GLOFs) by Medvezhi Glacier, Pamirs
The increasing number of glacial and moraine lakes in Central Asian mountains is a matter of great concern. One of the surging glaciers that poses a potential threat is the 15 km long Medvezhi (Bear) Glacier in the Pamir...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Cryosphere - winter seasons, Northern and Southern Hemispheres
Seasonal variation in the extent of ice and snow cover is greatest in the Northern Hemisphere. Imagine the Earth with white caps on the top and bottom. The top cap increases by a factor of six from summer to winter, whil...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Population, area and economy affected by a 1 m sea level rise (global and regional estimates, based on today's situation)
Even for today’s socio-economic conditions, both regionally and globally, large numbers of people and significant economic activity are exposed to sea-level rise. The densely populated megadeltas are especially vulnerabl...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Trends in Arctic sea ice extent in March (maximum) and September (minimum) in the time period of 1979–2008
For the Northern Hemisphere (primarily the Arctic), observations using remote sensing technologies have been used to measure the extent and the to assess the development. Despite considerable year-to-year variability, si...
18 Apr 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 mi...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Sea ice concentration change over the 21st century as projected by climate models
The data are taken from climate model experiments of 12 (out of 24) different models that were conducted for the IPCC Assessment Report 4 using the SRES A1B greenhouse gas emission scenario. Plots on the right show chang...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Arctic temperatures in the 20th century, modeled and observed
Observed Arctic winter land temperatures and IPCC model recreations for the 20th century. Note that although these model runs are able to capture the range of Arctic warm and cold periods, the timing of the peaks varies,...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Variations in snow depth and ice cover, alpine lake at Hardangervidda plateau, Norway
Climate warming means that lowland lakes typically are experiencing longer ice-free periods, promoting greater biological productivity. However, despite this warming trend, biological productivity may be reduced, at leas...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Arctic sea ice minimum extent in September 1982 and 2008
The red line indicates the median minimum extent of the ice cover for the period 1979–2000. This figure compares the Arctic sea ice extent in September for the years 1982 (the record maximum since 1979) and 2008. The ice...
18 Apr 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Ice avalanches of the Nevados Huascarán in Peru
Many disasters have been recorded from the glaciers in the Cordillera Blanca. The 1962 and 1970 events originating from Glaciar 511 on the Nevados Huascarán, the highest peak of which is at 6768 m above sea level in the ...
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, ...
01 Jun 2007 - by Stephan Gruber, University of Zürich. Hugo Ahlenius, UNEP/GRID-Arednal
Arctic delta pond ecosystems, seasonal flooding and adaptation
The physical development and ecosystem health of river deltas in cold regions are strongly controlled by ice processes and thus are highly susceptible to the effects of climate change. As an example, the photograph shows...
01 Nov 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Trends in snow-covered area for the Northern Hemisphere 1922-2005
Observations of snow-covered area for the Northern Hemisphere show a significant development in the later 20th century, with a reduction of the area covered by snow in the spring (March-April) from some 38 million km2 in...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Glaciers monitored through the World Glacier Monitoring Service
Worldwide collection of information about ongoing glacier changes was initiated in 1894 with the foundation of the International Glacier Commission at the 6th International Geological Congress in Zurich, Switzerland. Tod...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Projected changes in permafrost (Northern Hemisphere)
Modelled permafrost temperatures (mean annual temperature at the permafrost surface) for the Northern Hemisphere (Arctic), derived by applying climate conditions to a spatially distributed permafrost model. (a) Present-d...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Shrinking of Fedchenko Glacier in the Pamirs of Tajikistan
Significant loss of glaciers in Central Asia began around the 1930s, and become more dramatic in the second half of the 20th century and continue into the 21st century. Glacier area was reduced in the Tien Shan and in th...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Major research stations in Antarctica
Antarctica is interesting for many types of researchers. For example, glaciologists study the ice and snow, while oceanographers look at the oceans. The ice, snow and oceans affect the global climate and are presently ch...
31 Jul 2008 - by Hugo Ahlenius, UNEP/GRID-Arendal
Climate change - ice and snow and the albedo effect
Changes in the polar regions can cause more warming in the entire planet earth system through feedback effects. One such effect is the reduction of ice and snow due to warmer temperatures. When the white and gray snow an...
31 Jul 2008 - by Hugo Ahlenius, UNEP/GRID-Arendal
Arctic sea ice minimum extent in September 1982 and 2008
The red line indicates the median minimum extent of the ice cover for the period 1979–2000. This figure compares the Arctic sea ice extent in September for the years 1982 (the record maximum since 1979) and 2008. The ice...
31 Jul 2008 - by Hugo Ahlenius, UNEP/GRID-Arendal
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