Ice Fields, Glacial Milk, and Rising Seas

This Copernicus Sentinel-2 image shows the glaciers and lakes of the Southern Patagonian Ice Land between Chile and Argentina. As important indicators of climate change, the retreat of these glaciers over the past decades has implications for sea level rise. Credit: Modified Copernicus Sentinel data (2023), processed by ESA, CC BY-SA 3.0 IGO

The Southern Patagonian Ice Field, which straddles Chile and Argentina, is one of the largest ice sheets outside the polar regions. A recent image from Copernicus Sentinel-2 highlights its magnificent glaciers and aquamarine lakes.

A section of the southern Patagonian Ice Field with white glaciers and aquamarine lakes is featured in this Copernicus Sentinel-2 image from January 10, 2023.

It stretches 350 km (220 miles) across the Patagonian Andes on the border of Chile and Argentina and is one of the largest ice sheets on Earth outside the polar regions.

Formation and features of ice field

Snowfields are formed by the accumulation of ice sheets, which compress over many years and freeze into ice. Shaped by the underlying topography, glaciers often form at the edges of an ice field.

In this image, the glacier feeds several small and large glaciers, including Argentina’s Perito Moreno Glacier in the upper right corner. Located in a narrow channel, it feeds Lake Perito Moreno Argentino, forming an ice dam that separates the main body of the lake, its top visible in turquoise, and its southern arm, visible in gray.

Lakes, sediments and glaciers

Many lakes in the region are filled with glacial meltwater. The water color varies from deep blue to gray depending on the amount of suspended fine sediment. This sediment is called 'glacial milk’ and is the result of abrasion by glaciers as they flow over the underlying rock.

The largest glacier visible at the bottom of the image is the Gray Glacier, whose terminus is divided into three by landmasses. It is located within the Torres del Paine National Park, One of the largest in Chile. The name of the park comes from the three distinctive granite peaks 'Torres del Paine’ visible in the lower right corner of the image.

Moraines and indicators of climate change

The dark streaks that follow the flow of most glaciers are moraines: rock, soil, and other debris deposited by the glacier. A close look at the terminals of some glaciers shows how the icebergs have broken off and are now floating in fjords and lakes.

Glaciers are the largest freshwater reservoirs on our planet. The rate at which they melt or grow is one of the best indicators of climate change. Destruction of glaciers is one of the main causes of sea level rise. Many glaciers in Patagonia have retreated over the past 50 years. Satellite data can help monitor changes in glacier mass, size and thickness, and subsequently, their contribution to sea level rise.

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