About 100 glaciers are thought to have disappeared from the Swiss Alps since they reached their maximum extent in 1850. The percentage retreat is inversely proportional to the initial area of the glacier. Glacier where the original dimension (area, lenght and volume) were small have lost proportionally more ice in their retreat than larger glaciers. The small one thus appear to be more sensitive to climate change.

In connection with the 0.5-0.7°C warming since the middle of the 19th century, the total ice-covered areas in the Swiss Alps have declined from about 1800 km2 to 1300 km2. 27% of the areas existing in 1850 have disappeared. On average, swiss glaciers have lost about 490 m (35%) of their original extent since 1850. Glaciers have also narrowed by an average of 40 m. The total volume of ice diminished by approximately one-third (107 to 74 km3). Between 1850 and 1973, the line of equilibrium rose by approximately 70 m (from 2740 to 2810 m asl).

The most impacted zone is the central and northern Graubünden region, and the less impacted zone is the bernese Alps region.

On the european scale, the retreat is still more significant: Alpine glaciers have lost about half their volume of ice and 30-40% of their original area since 1850.

The + 100 m rise of the glaciers' line of equilibrium correspond to a 0.6-0.7°C warming. With a 100 m rise of the snow line (corresponding to year 2015 for IPCC scenario A or year 2025 for IPCC scenario C), a fifth of the present glaciers and a fourth of the glaciated area of the Swiss Alps will disappear, relative to the situation in 1973. In a + 200 m scenario, 847 of the 1923 existing glaciers will be left. In a +300 m scenario (timescale 2060-2130), over three-quarter of today's glaciers will already have disappeared.

The increasing slope erosion will probably accelerate in the periglacial areas and will affect various type of natural hazards: landslides, rock falls, floods, slope-type mudflows.

With its below-zero temperature, the permafrost can stabilize the base and front of the glaciers. But any change in the thermal conditions in the zone of contact between the glacier and the underlying rock may then produce differential movements within the ice. (e.g the Eiger glacier in the Bernese Oberland: local internal fracturing of a tongue ice at the western fank of the Eiger may cause local breack-up of ice; at least 100 000 m3 of ice are in danger of falling onto the Eigerletscher Station of the Jungfrau station. A monitoring system has been installed since 1990).

The increasing slope erosion will probably accelerate in the periglacial areas and will affect various type of natural hazards: landslides, rock falls, floods, slope-type mudflows.

A warming climate will also lead to the formation and enlargement of supra-/sub- glacial lakes resulting from retreat of the glacier snouts. Rising temperatures and heavy rainfall over glacial lakes may be expecetd to cause rapid melting of accumulated dead ice, enlargement of periglacial lakes and consequent bursting of moraine wall with a sudden emptying of sub-/peri- glacial lakes (GLOF, Glacial Lake Outburst Flooding). Global warming may moderate the temperature of the cold glaciers attached on very steep slopes and then affect their stability.