ABSTRACT

The earth’s is a story of change and adaptation. For example, during the midCretaceous, some 100 million years ago, temperatures were 8° to 15°C warmer than today (Figure 2.1). A host of tropical ora and fauna, like ferns and alligators, lived in warm, shallow seas at what is today Siberia and Canada’s Arctic. During the Cretaceous, the mean atmospheric concentration of CO2 was about 1,700 ppm. The Jurassic period of 200 million to 145 million years ago, which preceded the Cretaceous, was equally warm, and is best known as the Age of Reptiles, when dinosaurs roamed the earth. By the beginning of the Jurassic, the supercontinent Pangaea had begun to rift into smaller landmasses.