emirates7 - By examining 140-million-year-old oyster fossils, a team of Chinese and international scientists has uncovered new insights into Earth’s climate during the Early Cretaceous period, challenging the prevailing notion of a consistent warming trend and offering fresh perspectives on future climate predictions.
As reported by the Global Times, the study marks the first successful reconstruction of seasonal sea surface temperature fluctuations from this ancient greenhouse period. Through detailed analysis of fossilised oyster shells combined with high-resolution climate modeling, researchers identified distinct seasonal temperature swings and periodic episodes of glacial melting between approximately 139.8 and 132.9 million years ago.
These findings dispute the long-standing assumption that greenhouse periods experienced minimal seasonal variation and rare glaciation. Instead, they reveal that Earth’s climate during the Early Cretaceous was more dynamic and variable than previously believed, even under greenhouse conditions. This adds a new layer of complexity to our understanding of the planet’s long-term climate patterns.
The research, published online on May 3 in the journal Science Advances, was conducted by a collaboration including scientists from the Institute of Tibetan Plateau Research at the Chinese Academy of Sciences (CAS). Their work reveals that, despite high global temperatures and the prevalence of dinosaurs, the Early Cretaceous climate featured pronounced seasonal changes and possible intermittent glaciation—unlike today’s climate with year-round polar ice sheets.
Researchers noted that oysters, like trees, produce growth bands in their shells that reflect seasonal changes—lighter bands in summer and darker bands in winter. These patterns serve as natural archives of ancient environmental conditions.
Using sophisticated analytical tools, the team studied the growth bands and chemical signatures in exceptionally preserved oyster shells. They discovered that winter ocean temperatures in the Southern Hemisphere’s mid-latitudes were 10 to 15°C lower than in the summer—similar to modern seasonal differences in those regions.
Climate simulations further suggest that during summer months, glacial meltwater may have flowed into the oceans, resembling present-day patterns seen in Greenland, pointing to the occurrence of seasonal glaciation even in a greenhouse climate era.
The study underscores that climate change does not always follow a smooth, continuous warming path. Rising greenhouse gas levels could intensify seasonal contrasts and increase the chances of extreme and unpredictable weather events.
As reported by the Global Times, the study marks the first successful reconstruction of seasonal sea surface temperature fluctuations from this ancient greenhouse period. Through detailed analysis of fossilised oyster shells combined with high-resolution climate modeling, researchers identified distinct seasonal temperature swings and periodic episodes of glacial melting between approximately 139.8 and 132.9 million years ago.
These findings dispute the long-standing assumption that greenhouse periods experienced minimal seasonal variation and rare glaciation. Instead, they reveal that Earth’s climate during the Early Cretaceous was more dynamic and variable than previously believed, even under greenhouse conditions. This adds a new layer of complexity to our understanding of the planet’s long-term climate patterns.
The research, published online on May 3 in the journal Science Advances, was conducted by a collaboration including scientists from the Institute of Tibetan Plateau Research at the Chinese Academy of Sciences (CAS). Their work reveals that, despite high global temperatures and the prevalence of dinosaurs, the Early Cretaceous climate featured pronounced seasonal changes and possible intermittent glaciation—unlike today’s climate with year-round polar ice sheets.
Researchers noted that oysters, like trees, produce growth bands in their shells that reflect seasonal changes—lighter bands in summer and darker bands in winter. These patterns serve as natural archives of ancient environmental conditions.
Using sophisticated analytical tools, the team studied the growth bands and chemical signatures in exceptionally preserved oyster shells. They discovered that winter ocean temperatures in the Southern Hemisphere’s mid-latitudes were 10 to 15°C lower than in the summer—similar to modern seasonal differences in those regions.
Climate simulations further suggest that during summer months, glacial meltwater may have flowed into the oceans, resembling present-day patterns seen in Greenland, pointing to the occurrence of seasonal glaciation even in a greenhouse climate era.
The study underscores that climate change does not always follow a smooth, continuous warming path. Rising greenhouse gas levels could intensify seasonal contrasts and increase the chances of extreme and unpredictable weather events.