It was once a common belief that the Earth was around 6,000 years old.
This world view began to be discredited in the 18th century. Rock layers with fossils hinted at a long, long prehistory.
Over the past 200 years, scientists have shed more and more light on the Earth's 4.5 billion-year-old history.
That story is also about climate: We now know the Earth was covered in ice for millions of years at a time before advanced life came into existence. And that the Arctic was covered by forest 50 million years ago. At that time, alligators and monitor lizards lived in northern Canada and Germany was home to a subtropical jungle.
In his new book "Ild og is — En kort innføring I klimaets historie” (Fire and ice — A short introduction to the history of the climate), geologist Reidar Müller describes how the climate has changed over the course of the Earth's history.
