Ancient oyster fossils reveal climate patterns from 140 million years ago

A new international study has uncovered unexpected details about Earth's climate during the Early Cretaceous period by analysing 140-million-year-old oyster fossils. Published in a leading scientific journal, the research challenges traditional views of prehistoric greenhouse climates and provides insights relevant to modern climate change.

Using fossilised oyster shells as natural climate archives, researchers detected distinct seasonal temperature variations in ancient oceans. The shells' growth patterns, similar to tree rings, showed that winter temperatures in mid-latitude regions could be 10–15°C colder than summer temperatures, according to Global Times, a partner of TV BRICS.

Contrary to assumptions that greenhouse periods had mild seasons and little ice, the study found evidence of periodic glacial meltwater entering the oceans. This suggests that even during globally warm conditions, Earth experienced significant climate fluctuations, possibly driven by volcanic activity and changes in the planet's orbit.

By showing how natural factors once caused climate variability, the study provides a deeper understanding of potential climate scenarios as global temperatures continue to rise. These ancient fossils serve as a reminder that Earth's climate has always been dynamic, with patterns that sometimes defy expectations.

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