Extending over Chile and Argentina, the southern Patagonian icefield is the southern hemisphere’s biggest icefield outside of Antarctica, at approximately 13,000 sq km (5,000 sq miles). Most of its glaciers have retreated over the years and some are in grave danger. The glacier, named HPS-12, has experienced catastrophic retreat. In 1985, it was about 26km (16 miles) long, but in 2017 it was only 13km (8 miles) long, meaning that in the 33 years between the two images, the glacier lost about half its volume and detached from three other glaciers
Photograph: Nasa