Greenland Ice Sheet Reaches 'Tipping Point' Listen Download Embed Share Share this on Facebook (Opens in a new window) Share this on Twitter (Opens in a new window) Share this via Email Iceberg floating in the Nuup Kangerlua Fjord in southwestern Greenland, 2017. Greenland's glaciers have been melting and retreating at an accelerated pace in recent years due to warmer temperatures. ( David Goldman / AP Photo ) Produced by PRI and WNYC