Arctic glaciers were one of nature’s most enigmatic and unexplored wonders in the early 1900s. After more than a century of research, exploration, and exploitation, the glaciers have become a terrifying witness to the ravages of global warming.

Christian Slund, a Swedish photojournalist who works for Greenpeace, obtained some early images of glaciers and ice in Svalbard, Norway, from the Norwegian Polar Institute and juxtaposed them with his own photos from 2002 of the same sites. The difference between these before and after photographs was astounding. He’s using the photo series to support #MyClimateAction, a National Geographic campaign encouraging climate change conversation, and as a protest against Norwegian oil firms drilling in the Arctic region’s dwindling ice.

See each troubling comparison below, and sign Save The Arctic’s petition against Arctic oil here, in hopes of stopping the devastating consequences of global warming.

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7 Shocking Photos Show What Climate Change Has Done To Arctic Glaciers Over 100 Years