The tardigrade in the ice hole: how extreme life finds a way in the Arctic

Tiny organisms nicknamed water bears offer clues about possible alien life but the changing climate means their habitat faces an uncertain future

As we make our way across Greenland's ice sheets, I look around. We're surrounded by numerous tiny black holes, some only a few centimeters in diameter, others up to 4-8in (10-20cm) wide. As we advance, we notice that more and more holes are magically appearing, and their edges are increasingly distinct. They're called cryoconite holes.

Related: Greenland's ice melting faster than at any time in past 12,000 years