Subhajit Nan, Amity University, Kolkata
New research has found out that a drop in atmospheric carbon dioxide concentration caused a sudden high cooling of the temperature when dinosaurs roamed the world, resulting in the formation of polar ice caps.
Purpose of the Study
A thorough study of the effects of fluctuations in the levels of atmospheric CO2 in the distant past is essential in understanding how the heat currents move around the globe today. This, in turn, controls the amount of ice that can accumulate in the polar regions.
Background of the Study
The researchers found that the extreme climate changes in the Mesozoic Paleogene geological period led to the decrease in dissolved oxygen content in the ocean basins, major biodiversity crisis, and massive changes in wind and weather patterns. In the most extreme cases of oxygen depletion, certain parts of the Earth had oxygen-less ocean basins.
This event is known as the “Weissert Event”. It is described as an extreme climatic perturbation, spread over 700,000 years, that occurred nearly 133 million years ago, in the early-Cretaceous Period. In this study, this event has been its focus.
Though research had previously shown that all the climatic, physical, and biological components of nature are closely interrelated during such extreme climatic changes and fluctuations, the magnitude and the exact reason for the change in temperature due to the atmospheric CO2 concentration had not been a topic of discussion till now.
Salient Features of the Study
This study is the latest and most advanced research, undertaken for the climate fluctuations due to the Weissert Event, with cutting-edge geological data assessment and modeling. The aim was to demonstrate the link between the surface temperature of the sea and the change in the concentration of atmospheric CO2.
The researchers analyzed deep-sea sediments obtained by the Ocean Drilling Program (ODP) from offshore Antarctica. The sediments capture the Weissert Event in the semi-enclosed basin of the Weddell Sea. At that time, it was situated at 54°S paleo-altitude. It was very shallow, having a depth of about 500 meters.
For this study, they combined organic Carbon Isotopes of high-resolution and calibrated Sea Surface Temperature (SST) reconstructions. The results confirmed a drop of about 3°C to 4°C of the sea surface temperature in the Weddell Sea, near Antarctica, across the “Weissert Event”.
The new data from the Weddell Sea was combined with climatic model simulations and available information on the worldwide temperature from the geological record. They arrived at one unifying solution which provides a best-fit line of evidence. The outcome confirmed a 3.0 °C global mean surface cooling. This translates into a 40% drop in atmospheric carbon dioxide levels.
Conclusion
We can now predict what the consequences of a 40% drop in atmospheric CO2 level means, for surface ocean temperature distribution and unique marine and terrestrial environments.
Consistent with geologic evidence, the modeling suggests that this carbon dioxide concentration drop favored the eventual build-up of ice in the polar regions, both in the North and the South Poles.
Also read: Wind energy: Winding down Earth’s climate change crisis
References: –
- Cavalheiro, L., Wagner, T., Steinig, S., Bottini, C., Dummann, W., Esegbue, O., Gambacorta, G., Giraldo-Gómez, V., Farnsworth, A., Flögel, S., Hofmann, P., Lunt, D. J., Rethemeyer, J., Torricelli, S., & Erba, E. (2021). Impact of global cooling on Early Cretaceous high pCO2 world during the Weissert Event. Nature Communications, 12(1), 5411. https://doi.org/10.1038/s41467-021-25706-0
Author info:
Subhajit Nan is an aspiring biotechnologist, living in Kolkata. He is currently in his second year, pursuing a Bachelor of Science (Honours) in the field, from Amity University, Kolkata. Subhajit has completed his schooling at Calcutta Boys’ School in the Science stream. He has a keen interest in scientific research and writing. He likes debating, playing chess, and swimming in various competitions.
Other Publications of the Author: –
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