Climate - Extinctions

It has been suggested that increased volcanic and submarine spreading activities during the Jurassic period led to the release of large amounts of the greenhouse gas carbon dioxide, which increased global temperatures. Higher temperatures and a smaller latitudinal gradient may also be associated with the Tethys Sea, which distributes warm tropical seas around the globe. Higher temperatures, the lack of a density gradient in the oceans and weaker winds may have caused a much slower ocean circulation. As mentioned above, there is no evidence of glaciers or polar ice caps in the Jurassic. This could be due to the absence of polar continents or warmer temperatures in general, but the relationship between temperature, topography and glaciation is complex and it is difficult to state a clear causal relationship.


The Early Jurassic is a period when animals and plants living on land and in the sea survived the largest mass extinction in Earth's history. Most vertebrates and invertebrates important in modern society first appeared in the Jurassic. In the oceans, particularly diverse organisms emerged, including coral reef ecosystems, shallow-water invertebrate faunas and large swimming predators such as reptiles and squids. On land, dinosaurs and flying pterosaurs dominated ecosystems and birds appeared for the first time. Early mammals were also present, but still very few. Insects were very diverse and plants were dominated by open seeds.