The Earth’s temperature and weather patterns change naturally over time scales ranging from decades, to hundreds of thousands, to millions of years1. The climate is the statistical average of the weather taken over a long period, typically 30 years. It is never static, but subject to constant disturbances, sometimes minor in nature and effect, but at other times much larger. In some cases these changes are gradual and in others abrupt.
Book
The Geological Society
The Geological Society
2010