The Leonard Lopate Show Published by The Leonard Lopate Show On Thin Ice Download this audio Want to embed this player? Use the code below. More info. <iframe frameborder="0" scrolling="no" height="130" width="100%" src="https://www.wnyc.org/widgets/ondemand_player/wnyc/#file=/audio/json/60060/&share=1"></iframe> Share on Facebook Share on Twitter Email a Friend Science writer Richard Ellis talks about how the polar bear has become a symbol of how climate change threatens life on the planet. In On Thin Ice: The Changing World of the Polar Bear, he looks at why the world population of polar bears has shrunk by half in the last 20 years.