Oyster fossils unveil ancient seasonal climate secrets

An international research team led by the Chinese Academy of Sciences has uncovered striking evidence of seasonal temperature swings and glacial cyclic activity during the greenhouse period in Earth's past, offering new insights into today's climate challenges.

The study, published on Saturday in Science Advances, is the first to reconstruct the history of seasonal fluctuations in sea surface temperatures during a greenhouse Earth period, discovering that during the Early Cretaceous period (139.8-132.9 million years ago), the Earth exhibited significant seasonal temperature variations and periodic melting of polar ice sheets and glaciers.

The findings challenge long-held assumptions about stable, ice-free conditions during prehistoric warm eras, said Ding Lin, an academician from the Institute of Tibetan Plateau Research of CAS, who led the study.