Just twenty thousand years ago, ice kilometres thick buried much of the northern world, and the sea was so much lower you could walk between continents. We explore what the ice ages were, the elegant astronomical clockwork that drives them, how we read this history from ice and mud, and what it does and doesn't tell us about the warming happening now.

You'll come away understanding the difference between an "ice age" and a "glacial period," how tiny wobbles in Earth's orbit set the rhythm of the ice, how feedbacks amplify those nudges, and why today's warming is a different kind of event from the natural cycles of the past.

Talking Science is sponsored by Kinsoft. Visit www.kinsoft.com.au

Further reading: the NOAA Paleoclimatology program; the EPICA  ...