Well I have no idea what ice age he is referring to that 'began' 15,000 years ago!

The Wisconsin Glaciation is normally dated from 115,000 to 12,000 years ago with last glacial maximum (LGM) occurring at 22,000 years ago. Now these dates vary depending on who is defining the boundary and what area of the planet is being considered but basically, 15,000 years ago the glaciers had started a gradual retreat from their maximum extent.