For more than 30 years, photographer James Balog has been seeking new ways to visualize the natural world. His artistry has been featured in dozens of magazines, from National Geographic to The New Yorker. But his most recent project, the Extreme Ice Survey (EIS), has a scientific goal. It seeks to document an unprecedented melting of the world's glaciers, a phenomenon that many scientists agree is proof of human-caused global warming.

As director of the EIS, Balog considers himself a modern hunter-gatherer, collecting vital information to feed a public hungry for real evidence of climate change. In this audio slide show, let Balog whet your appetite in his own words.—David Levin

Read the PBS article.