Tag: Ice

Trends in the ice-breaking date in the Tornio river, Finland
The icebreaking date for the Tornio River in Finland has been recorded since 1693. With the increased greenhouse effect, impacts on the cryosphere are likely. One impact will be less ice on rivers and lakes. Freeze-up da...
12 Feb 2006 - by Philippe Rekacewicz, UNEP/GRID-Arendal
Rising water levels in the Spitamen district (Tajikistan)
Sudden releases of water into the Spitamen district from Kyrgyzstan are regularly endangering the neighboring Tajik arable land downstream and villages along the river. The Tajik communities are convinced upstream Kyrgyz...
16 Mar 2006 - by Viktor Novikov, UNEP/GRID-Arendal
Arctic map, political
The Arctic is extremely diverse in terms of landscapes, varying from pack and drift ice to rugged shores, flat coastal plains, rolling hills and mountains surpassing 6000 metres above sea level (Denali, 6,194 m asl, in s...
16 Sep 2006 - by Hugo Ahlenius, UNEP/GRID-Arendal
Projected changes in the Arctic climate, 2090 - with shipping routes
The averages of the scenarios in the Arctic Climate Impact Assessment (ACIA) are presented in this figure, for the year 2090, with the surface temperatures over land, the size of the polar ice cap, and the outer limits o...
16 Sep 2006 - by Hugo Ahlenius, UNEP/GRID-Arendal
Barents Sea - Oil free zones
Proposal from the World Wildlife Fund for Nature (WWF) for permanent petroleum-free zones in the Barents Sea. Areas covered with ice for parts of the year are also included in the proposed zones. The map has been drawn u...
01 Nov 2006 - by Hugo Ahlenius, UNEP/GRID-Arendal
Fossil fuel resources and oil and gas production in the Arctic
The Arctic has been opened up for increased exploration of petroleum, gas and mining activities. The Barents Sea, the Mackenzie Valley in Canada and the Alaskan North Slope, are the areas of chief interest at the moment....
06 Dec 2006 - by Philippe Rekacewicz & Hugo Ahlenius UNEP/GRID-Arendal
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 rat...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Time series of freeze-up and break-up dates from selected Northern Hemisphere lakes and rivers, 1846–1995
Limited by the availability of detailed observations, most historical evaluations of changes in freshwater ice have focused on relatively simple characteristics, such as the timing of autumn freeze up and spring break up...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Overview of world glaciers and ice caps
By far the largest area of glaciers and ice fields are found in Canada (about 201 000 km2), followed by Alaska (about 75 000 km2) with about 700 km2 in the rest of the USA. Glaciers and ice fields are concentrated in th...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Mass balance of Maliy Aktru Glacier, Russian Altai
Measurements on this valley-type glacier in the North Chuyskiy Range show a slightly negative annual mass balance trend culminating in an ice loss of about 4 m water equivalent over the period 1964–2005.
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Northern Hemisphere snow-cover extent anomalies 1966-2005
Data from satellite monitoring from 1966 to 2005 show that mean monthly snow-cover extent in the Northern Hemisphere is decreasing at a rate of 1.3 per cent per decade. For the calendar year of 2006 average snow-cover ex...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Projected temperatures in the 21th century
Projected Arctic annual land temperature increases for the first half of the 21st century relative to the average temperature for 1980–99. The average of the IPCC models (the blue line) shows an increase of 3ºC by 2050. ...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Temperatures over previous centuries from various proxy records
Evidence from tree rings and other temperature proxies suggests that during the previous 500 years global temperatures were 1.0ºC cooler than those of the 20th century during a period roughly from 1300 to 1870 – known as...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Antarctica, showing rates of surface-elevation change derived from satellite radar-altimeter measurements
The figure shows rates at which the ice-sheet mass was estimated to be changing based on radar-altimeter data (black), mass-budget calculations (red), and satellite gravity measurements (blue). Rectangles depict the time...
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 ce...
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 mi...
01 Oct 2008 - by Hugo Ahlenius, UNEP/GRID-Arendal
Albedo of basic thick sea ice surface types
The albedo for different surface conditions on the sea ice range widely, from roughly 85 per cent of radiation reflected for snow-covered ice to 7 per cent for open water. These two surfaces cover the range from the larg...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Change in the age of ice on the Arctic Ocean, comparing September ice ages in 1988, 1990, 2001 and 2005
The age of sea ice in the Arctic is changing, and not only the extent and concentrations. Studies show that in recent years there is a higher proportion of younger ice to older ice than was observed in the late 1980s. Th...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Melting ice on Mount Kilimanjaro, East Africa
Close to 50 per cent of the glaciers in Africa, on the Rwenzori Mountains, Mount Kenya and Kilimanjaro have disappeared, while larger glaciers – particularly on Kilimanjaro – have been fragmented. Changes in glacier area...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
Ice-albedo feedback process
In spring, the ice is snow-covered and there is very little open water. Most sunlight is reflected, but some is absorbed. This absorbed sunlight leads to melting, which in turn reduces the ice albedo and increases the am...
01 Jun 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
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