The changing face of the Chilean glaciers in the Laguna San Rafael National Park is featured in these satellite images from 1987 and 2024.

Located on the Pacific coast of southern Chile, the park covers an area of around 17 000 sq km and includes the Northern Patagonian Ice Field – a remnant of the Patagonian Ice Sheet that once covered the region. Today, despite the ice field being just a fraction of its previous size, it is still the second largest continuous mass of ice outside the polar regions.

As we can see in the images, the ice mass feeds glaciers that have changed in size between 1987 and 2024. The Landsat-5 image on the left was acquired on 9 February 1987, while the image on the right captured the ice field on 9 February 2024 as seen by the Copernicus Sentinel-2 mission.

The west part of the Northern Patagonian Ice Field feeds 28 exit glaciers. The largest two, San Rafael and San Quintín, are pictured here. Both glaciers have been receding dramatically due to global warming.

The San Rafael glacier, in the upper left, is one of the most actively calving glaciers in the world. It calves west towards the Pacific Ocean and into an arc-shaped lake, Laguna San Rafael, visible directly to the left of the glacier. The lake is formed and fed by the retreat of the glacier.

Like Laguna San Rafael, many lakes in the area are fed by water from melting glaciers. In the images, the colour of the water varies from dark blue to aquamarine depending on the amount of suspended fine sediment present. This sediment is called ‘glacier milk’ and is a result of abrasion as glaciers move over the underlying rock. This is particularly clear in San Rafael lake, where we can also see icebergs floating in the water.

Directly below San Rafael lies the San Quintín glacier, the second largest in the ice field. The glacier drains to the west and, taking a closer look at its terminus in both images, we can see how, in 1987, the glacier almost terminated on land, but, with its retreat, the basin filled with water and formed the proglacial lake we see in 2024.

Glaciers around the world are affected by climate change. As temperatures rise and glaciers and ice sheets melt, the water eventually runs into the ocean, causing sea levels to rise. Rising seas are one of the most distinctive and potentially devastating consequences of Earth’s warming climate.

Satellite observations can greatly contribute to the precise monitoring of glacier change. The pace at which glaciers are losing mass in the long term is very important to making informed future adaptation decisions.