The concentration of carbon dioxide (CO2) in the atmosphere today is the highest in a long time. According to a new study published recently in the journal Geology, scientists have found that today’s atmospheric CO2 concentrations are above the previous record of 23 million years and are soaring at an unprecedented rate.
Since industrialization, human demand for development has been escalating and greenhouse gas emissions have become more and more robust. Long-term studies have shown that since the beginning of the 19th century, CO2 concentrations have risen sharply, around the time of the Industrial Revolution. Currently, CO2 is considered to be one of the most greenhouse-effect pollutants, and elevated CO2 concentrations are closely related to climate change. Currently, there are direct records dating back hundreds of years, but before that, the picture was very vague. The ice cores drilled by scientists allow people to “see” what they looked like 2.7 million years ago, when CO2 concentrations were less than 300 ppm.
In the latest study, researchers at Louisiana State University looked further afield, going back 23 million years. The team achieved this by studying the fossil remains of ancient plants. Because as plants grow, they absorb CO2 from the atmosphere, and plant tissue retains certain stable carbon isotopes, especially carbon-12 and carbon-13. When these plants become fossils, scientists can study isotope levels to determine the co2 concentration of plants when they grow.
Using this method, the team found that over the course of 23 million years, co2 concentrations mostly fluctuated between 230 ppm and 350 ppm. This is far below the modern level. The study also found that in the long past, CO2 concentrations have never risen as sharply as we are now.
Over the past 23 million years, the researchers note, warming events have been linked to increases in CO2 concentrations, including the Mid-New Olympics, which occurred between 15 million and 17 million years ago, and the Mid-New Pleistocene, 3 to 5 million years ago.
Last May, data from hawaii’s Monaroa Observatory showed co2 concentrations hit a new high of 415.26 ppm, the highest in human history. Now this latest study is further evidence of the seriousness of the challenges facing humans today.