The composition of fossilised zooplankton shells has enabled the reconstruction of past pH and CO2. Credit: University of Southampton
July 10, 2020 (Phys.org) -- By 2025, atmospheric carbon dioxide (CO2) levels will very likely be higher than they were during the warmest period of the last 3.3 million years, according to new research by a team from the University of Southampton published today in Nature Scientific Reports.
The team studied the chemical composition of tiny fossils, about the size of a pinhead collected from deep ocean sediments of the Caribbean Sea. They used this data to reconstruct the concentration of CO2 in Earth's atmosphere during the Pliocene epoch, around 3 million years ago when our planet was more than 3°C warmer than today with smaller polar ice caps and higher global sea-levels.
Dr. Elwyn de la Vega, who led the study, said: "Knowledge of CO2 during the geological past is of great interest because it tells us how the climate system, ice sheets and sea-level previously responded to the elevated CO2 levels. We studied this particular interval in unprecedented detail because it provides great contextual information for our current climate state."
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