Earth’s Dynamic Climate
Scientists have long known that the Earth’s climate is dynamic,
fluctuating between colder and warmer periods generally
referred to as glacial and interglacial states (Figure 1). Despite
these swings, the Earth has supported life for the past four million
years. Historically, climate changes have usually occurred
on timescales of thousands of years, although there well-documented
exceptions such as the Younger Dryas when climate
change has occurred more quickly