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UL Lafayette research could yield critical information on global warming

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CO2 levels now higher than any time in the last 23 million years

One of the most pressing messages that climate scientists attempt to convey to the public is how today’s CO2 levels compare to those of the Geologic past. Such comparisons can provide public context for current CO2 rise, as well as important information on the response of global temperatures to rising CO2. A new study published in Geology suggests that present-day CO2 levels (412 ppmv) are now likely higher than at any time in at least the last 23 million years!

In this newly published study, a team led by Brian Schubert, Associate Professor in the School of Geosciences at the University of Louisiana at Lafayette, used the remains of dead plants to produce a new record of atmospheric CO2 that spans 23 million years of uninterrupted Earth history. Their findings relied on the nearly continuous record of terrestrial photosynthesis provided by organic matter accumulated from partially decomposed plants.

“When plants grow, the relative amount of the two stable isotopes of carbon, carbon-12 and carbon-13, changes in response to the amount of CO2 in the atmosphere,” says Schubert. “One can therefore measure the relative amount of these two isotopes and calculate the CO2 concentration under which the plants grew.”

The remains of land plants can be used to calculate the amount of CO2 in Earth’s atmosphere. Photo credit: A. Hope Jahren

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Two Graduate Students win the GSA Graduate Research Grant

Please join us in congratulating two of our graduate students who recently won a GSA Graduate Research Grant for 202

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The School of Geosciences wins prestigious Field Camp Award

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UL Lafayette research could yield critical information on global warming Dr. Brian Schubert and Dr. Ying Cui in the School of Geosciences have received a $347,945 grant from NSF to study the connection between atmospheric carbon dioxide levels and global temperatures. This study aims to gain a better understanding of how sensitive Earth’s temperature is to changing levels of atmospheric carbon dioxide.

Carbon dioxide is the main greenhouse gas responsible for controlling global temperatures. Our understanding of the link between temperature and carbon dioxide is based only on relatively recent historical data and ice cores dated to less than 1 million years old, when carbon dioxide levels were not much different from today. However, a growing body of evidence suggests that Earth has experienced very large fluctuations in both temperature and carbon dioxide. “For example, 55 million years ago, parts of the Arctic looked a lot more like southern Louisiana than the tree-less tundra that exists today,” said Dr. Brian Schubert, an assistant professor in the University of Louisiana at Lafayette’s School of Geosciences. “However, the amount of carbon dioxide in the atmosphere during this time is poorly understood.”

“We will use thousands of carbon isotope data and the known relationship between carbon isotope fractionation and atmospheric carbon dioxide concentration to reconstruct paleo-pCO2 during the Cenozoic” said Dr. Ying Cui, a postdoctoral researcher in the University of Louisiana at Lafayette’s School of Geosciences. Carbon has two isotopes – carbon 12 and carbon 13 - that are used by plants during photosynthesis and are affected by the amount of carbon dioxide in the atmosphere at the time the plants were growing. When the plants die, this information is preserved in the rocks as organic matter. By studying small changes in these two isotopes, the researchers will be able to produce a precise record of how much carbon dioxide levels have changed across the last 65 million years.

By comparing these data with existing temperature data, the team hopes to provide a better understanding of the response between temperature and carbon dioxide. This approach will provide important information for understanding how much temperatures will rise in the coming centuries as a result of fossil fuel burning.

“These data are critical for implementing policies related to climate risk management,” said Dr. Ying Cui. This project will also involve University of Louisiana at Lafayette students, providing them with new tools and original research experiences. Results from this work will be incorporated into course material and help fulfill the School of Geosciences’ mission to provide education and research focused on Energy and the Environment.

NSF awards grants for research and education in the sciences, mathematics, and engineering.