The European Alps span over 600 miles (1,000 kilometers) across eight European countries and host thousands of glaciers in their cooler upper regions. Recently, NASA satellite images have documented a 40-year retreat of the Alps’ largest glacier, the Great Aletsch Glacier. These images, taken in 1984 and 2024 by NASA’s Landsat 5’s Thematic Mapper and Landsat 8’s Operational Land Imager (OLI), respectively, illustrate significant changes in the glacier’s length and width, indicating a retreat of more than 4,300 feet (1,300 meters) during this period.
According to a release from NASA’s Earth Observatory, the glacier has thinned by approximately 141 feet (43 meters) in water depth, as reported by the Swiss Glacial Monitoring Network (GLAMOS), demonstrating shrinkage in both dimensions. Despite some cloud cover in the recent images, the reduction in ice is evident, with grayish-brown rock now exposed where bright white ice once reflected light back into the atmosphere. The release noted that it was too early in the year to capture images without seasonal snow, which currently covers much of the glacial melt that has occurred.
The retreat of glaciers in the Alps is widespread. Nearby, the Oberaletsch glacier has retreated more than 787 feet (240 meters) since 1984, while the Fiescher Glacier has experienced a retreat of 3,281 feet (1,000 meters) over the same timeframe.
A report by Reuters indicated that Swiss glaciers melted at an above-average rate in 2024, despite heavy snowfalls during winter and spring. These winter storms were insufficient to offset record ice losses due to a warm August and the presence of Sahara desert dust, which reduced the glaciers’ ability to reflect sunlight.
In 2024, Swiss glaciers lost 2.5% of their volume, based on Reuters data. Central Europe, including Switzerland, has seen a dramatic 39% decline in its glacial ice between 2000 and 2024, according to a study published in Nature this year.
The NASA imagery highlights the dramatic changes occurring. Following a record warm February, which was the third-warmest on record according to the National Oceanic and Atmospheric Administration, there is concern and anticipation that more images documenting glacial losses will surface in the near future.
