Dinosaurs lived in greenhouse climate with hot summers

New climate reconstruction method provides precise picture of climate 78 million years ago. Palaeoclimatologists study climate of the geological past. Using an innovative technique, new research by an international research team led by Niels de Winter (VUB-AMGC & Utrecht University) shows for the first time that dinosaurs had to deal with greater seasonal differences than previously thought. De Winter: "We used to think that when the climate warmed like it did in the Cretaceous period, the time of the dinosaurs, the difference between the seasons would decrease, much like the present-day tropics experience less temperature difference between summer and winter. However, our reconstructions now show that the average temperature did indeed rise, but that the temperature difference between summer and winter remained rather constant. This leads to hotter summers and warmer winters." To better characterize the climate during this period of high CO₂ concentration, the researchers used very well-preserved fossils of mollusks that lived in southern Sweden during the Cretaceous period, about 78 million years ago. Those shells grew in the warm, shallow seas that covered much of Europe at the time.