Dr. Zhang has co-authored a study revealing that Earth’s carbon dioxide atmospheric concentrations averaged 250 parts per million for 2.5 million years. For refernece, today’s levels are about 410 parts per million.
On September 25, 2019, the research “Low CO2 levels of the entire Pleistocene Epoch” published in Nature Communications and has intrigued media and public audience by its findings.
Conventional “gold-standard” records of atmospheric carbon dioxide are commonly retrieved from ice cores. However, the ice-derived carbon dioxide records extend back only for the last 800,000 years. With Dr.Zhang’s co-authored study, soil carbonates from Leoss Plateau in central China recorded information that scientists can use for reconstructing Earth’s atmospheric carbon dioixide concentrations extending back since 2.5 million years ago (Ma). The study shows that the average level of carbon dioxide over the last 2.5 Ma was 230 parts per million (ppm).
“According to this research, from the first Homo erectus, which is currently dated to 2.1 to1.8 million years ago, until 1965, we have lived in a low-carbon dioxide environment — concentrations were less than 320 parts per million,” said Dr. Zhang, “We evolved in a low-carbon-dioxide environment, and how humans will evolve and be affected by today’s carbon-dioxide levels is yet to be seen.”
If you don’t want to miss what others are talking about, please check out articles in the media:
Nature communitcations: https://www.nature.com/articles/s41467-019-12357-5
Texas A&M Today: https://today.tamu.edu/2019/09/25/humankind-did-not-live-with-a-high-carbon-dioxide-atmosphere-until-1965/
September 25, 2019 – Dr.Zhang gave some insights about the newly-published study on television at KBTX-TV: https://www.kbtx.com/templates/2015_Sub_Video_Share?contentObj=561567141