**Carbon Dioxide Levels at a Record High in 14 Million Years**
The levels of carbon dioxide in the atmosphere, currently at a record high of 419 ppm, are the highest they have been in 14 million years. This spike in CO2 concentrations can be attributed to human activities, particularly the burning of fossil fuels. An international team of scientists is examining geological markers to reconstruct Earth’s CO2 history and to find out where the current concentrations fit in the Earth’s history.
The team, known as the Cenozoic CO2 Proxy Integration Project (CenCO2PIP), is examining a variety of markers in the geologic record that offer clues about the contents of ancient atmospheres. They are relying on indirect evidence, also known as proxies, which includes isotopes in minerals and the morphology of fossilized leaves, to reconstruct the CO2 levels. The research has involved nearly 90 scientists from 16 different countries and has received multiple grants from various agencies.
The study was led by University of Utah geologists who have found that the current 419 ppm concentration is unprecedented in recent geologic history. Gabe Bowen, a geology professor at the university and one of the study’s corresponding authors, stated, “By 8 million years before present, there’s maybe a 5% chance that CO2 levels were higher than today, but really we have to go back 14 million years before we see levels we think were like today.”
Looking ahead, these high levels of CO2 are expected to continue to rise, potentially impacting the future climate. William Anderegg, a biology professor at the University of Utah, stated, “Having a reliable map of past CO2 levels could help scientists more accurately predict what future climates may look like.”
The findings of this research will not only help predict future climate changes but also provide valuable insights into the Earth’s history and its various periods of mass extinctions and evolutionary innovations.
The full research findings are available in the journal Science, published on December 8, 2023.