Passive microwave sensors on satellites have monitored the extent of the sea ice cover since 19782. This technique is widely used to investigate fluctuations in ice extent over the seasons, variability between years, and longterm trends. The seasonal variation of ice extent is much greater in the Antarctic where there is about six times as much ice in winter as in summer. Currently, in the Arctic, ice approximately doubles from summer to winter. ...

Mass-balance estimates for Greenland show thickening at high elevations since the early 1990s at rates that increased to about 4 cm per year after 2000, consistent with expectations of increasing snowfall in a warming climate. However, this mass gain is far exceeded by losses associated with large increases in thinning of the ice sheet near the coast. Total loss from the ice sheet more than doubled, from a few tens of billions of tonnes per year ...

Trends in development and urbanization show that the gaps between the rich and the poor is generally increasing world wide. This satellite image over Nairobi, Kenya highlights the location of golf courses and informal settlements (e.g. slums, squatters) and they are, in a few cases, next door to each other - highlighting the contrasts.

Comparing a series of satellite images from different periods a Californian hydrologist discovered in 1983 that a huge white spot had taken the place of the vast Kara-Bogaz- Gol (literally “dark gullet” in Turkmen) in the south-east corner of the Caspian. Kara-Bogaz-Gol is a lowland area that forms a highly saline bay on the east side of the Caspian Sea, in Turkmenistan.

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 extent was 24.9 million km2, which is 0.6 million km2 less than the 37-year average. In the Northern Hemisphere, spring and summer show the strongest decreases in snow-cover extent. Satellite observations of snow-cover extent show a...

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 periods of observations (horizontal) and the upper and lower estimates of mass balance (vertical). Measurements by satellite techniques based on gravity indicate mass loss at a rate of 138 ± 73 billion tonnes per year during 200...

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. This analysis is based on results from a simulation using drifting buoy data and satellite-derived ice-concentration data. The darker the colour, the older the ice.

A new glacier inventory based on satellite data shows that the glacier cover reduced by about 22 per cent between the Little Ice Age (LIA) maximum extent and 2000. Changes in glacier area and volume are being used as indicators for climate change and global warming.

Coastal and island tide-gauge data show that sea level rose by just under 20 cm between 1870 and 2001, with an average rise of 1.7 mm per year during the 20th century and with an increase in the rate of rise over this period. This is consistent with the geological data and the few long records of sea level from coastal tide gauges. From 1993 to the end of 2006, near-global measurements of sea level (between 65°N and 65°S) made by high precision s...

Mass-balance estimates for Greenland show thickening at high elevations since the early 1990s at rates that increased to about 4 cm per year after 2000, consistent with expectations of increasing snowfall in a warming climate. However, this mass gain is far exceeded by losses associated with large increases in thinning of the ice sheet near the coast. Total loss from the ice sheet more than doubled, from a few tens of billions of tonnes per year ...

There are major regional differences for the Arctic sea ice, with the strongest decline in ice extent observed for the Greenland Sea (10.6 per cent per decade). The smallest decreases of annual mean sea ice extent were found in the Arctic Ocean, the Canadian Archipelago and the Gulf of St. Lawrence. In the marginal Arctic seas off Siberia (the Kara, Laptev, East Siberian and Chukchi Seas) a slight negative, but not significant, trend in ice exten...

An ice-rock avalanche in the Kazbek region sheared off almost the entire Kolka Glacier and devastated the Genaldon valley. The satellite images show the region before (July 22, 2001) and after (October 6, 2002) the ice-rock avalanche of September 20, 2002.

A new glacier inventory based on satellite data shows that the glacier cover reduced by about 22 per cent between the Little Ice Age (LIA) maximum extent and 2000. Changes in glacier area and volume are being used as indicators for climate change and global warming.

An ice-rock avalanche in the Kazbek region sheared off almost the entire Kolka Glacier and devastated the Genaldon valley. The satellite images show the region before (July 22, 2001) and after (October 6, 2002) the ice-rock avalanche of September 20, 2002.

Mass-balance estimates for Greenland show thickening at high elevations since the early 1990s at rates that increased to about 4 cm per year after 2000, consistent with expectations of increasing snowfall in a warming climate. However, this mass gain is far exceeded by losses associated with large increases in thinning of the ice sheet near the coast. Total loss from the ice sheet more than doubled, from a few tens of billions of tonnes per year ...

The current vegetation density and distribution in the high Arctic can be calculated using satellite images. The vegetation index, 'greenness' (NDVI) represents a benchmark of the presence and ratio of photosynthesis. In monitoring the vegetation, scientists can keep an eye on the situation and use the index as an indicator of climate change - increased temperatures would enable the forest and tundra to move further north.

Satellite altimetry data has revealed that sea level is not rising uniformly.

A very high-resolution false color Ikonos-2 satellite image of Jauristunturit in the border zone shared by Norway and Finland. Image acquired 28 June 2001. The main vegetation type is lichen dominated tundra heath with dwarf shrubs. The difference in whiteness is due to lichen coverage, and the national border with reindeer fence visibly divides the area. The northern portion is Norway, where fruticose lichen coverage is higher. This is a consequ...

Arctic vegetation has undergone enormous change in the past, most notably in response to the glacial and interglacial periods of the Quaternary. Data from many sources and at several scales suggest that recent climate change is already affecting terrestrial Arctic ecosystems. Comparisons of historical and contemporary aerial photographs provide evidence that Arctic vegetation has already undergone significant shifts in recent decades, foreshadowi...

The Circumpolar Arctic Vegetation Map (CAVM) project is an international effort to map the vegetation and associated characteristics of the circumpolar region, using a common base map. The base map is a false colour infrared image created from Advanced Very High Resolution Radiometer (AVHRR) satellite data.