Paleoclimatologists have precisely reconstructed monthly sea surface temperatures at around 50 °N latitude from fossil shells of bivalve mollusks that lived during the Campanian (Late Cretaceous epoch) greenhouse period, about 78 million years ago. Cretaceous-period dinosaurs had to deal with greater seasonal differences than previously thought. Image credit: Sergey Krasovskiy. “We used to think that when the climate warmed like it did in the Cretaceous...
