Photographer Page

Esther Horvath

Wind chill describes how cold the combination of air temperature and wind feels. In the Arctic, where scientists conduct research, 60 mph winds can produce -67°F wind chills.

PBI's Joanna Sulich, Kyle Schutt, Alysa McCall, and K.T. Miller prepare for students in Tundra Buggy One research and outreach mobile lab.

Geoff York checks polar bear radar instruments.

B.J. Kirschhoffer, director of conservation technology at PBI, is the developer of the organisation's polar bear radar program and software. The radar can distinguish between polar bears and people, cars, or other animals.

Geoff York, senior director of conservation and staff scientist at Polar Bears International, checks a polar bears radar software and program.

A polar bear approaches a buggy belonging to Polar Bears International in Churchill, Canada, on November 8, 2022.

A cryo-workbench in the bunker allows the samples to be checked and analyzed without interrupting the cold chain—which is essential for preserving them as a long-term record.

Some 400,000 samples are stored in the bunker outside Münster, and new ones are added every year from four sampling locations around Germany.

Till Weber, a scientist at the German Environment Agency, manages the specimen bank. It began operating in 1985 and maintains the world's most consistent record—and one of the longest—of humans' changing chemical burden.

Inside the tanks, liquid nitrogen keeps the samples in a deep freeze below -256ºF. The vials are stored in racks that sit in the cloud of gaseous nitrogen above the liquid.