Ice Ages: Timeline

Past 1,000,000 years

Past 150,000 years

Using chemical information collected from ice cores and from shells of organisms preserved in deep-sea sediments, geologists have been able to map out how Earth's climate has changed over time. Climate swings between cold periods, called glacials, and warm periods, called interglacials. We are currently in an interglacial. What causes these changes in climate? »