Polar forests of the Cretaceous Polar forests of the Cretaceous Cretaceous polar forests were temperate forests that grew at polar latitudes during the final period of the Mesozoic Era, known as the Cretaceous Period 145–66 Ma. During this period, global average temperature was about higher and carbon dioxide (CO) levels were approximately 1000 parts per million (ppm), 2.5 times the current concentration in Earth's atmosphere. The abundance of atmospheric carbon dioxide had a very significant impact on global climate and Earth's natural systems as its concentration is considered one of the main factors in the development of a pronounced greenhouse Earth during the Cretaceous with
Triassic amphibians, the first Lissamphibia, progenitors of first frogs, are known from the Early Triassic, but the group as a whole did not become common until the Jurassic, when the temnospondyls had become very rare. Other survivors the Chroniosuchia and Embolomeri were more closely related to amniotes than temnospondyls. Those became extinct after some million years. Most of the Reptiliomorpha, stem-amniotes that gave rise to the amniotes, disappeared in Triassic, but two water-dwelling groups survived; Embolomeri that only survived into the early part of the period, and the Chroniosuchia, which survived until the end of Triassic. Archosauromorph reptiles, especially archosaurs, progressively