Scientists have discovered that the atmosphere contained far less CO2 than previously thought when forests emerged on our planet, the new study has important implications for understanding how land plants affect the climate.
The new research has been led by the University of Copenhagen in collaboration with the University of Nottingham and alters 30 years of previous understanding. The study is published in Nature Communications.
Earth’s continents were colonized by tall trees and forests about 385 million years ago. Before then, shallow shrub-like plants with vascular tissue, stems, shallow roots, and no flowers had invaded the land. Textbooks tell us that the atmosphere at that time had far higher CO2 levels than today and that an intense greenhouse effect led to a much warmer climate. The emergence of forests was previously thought to promote CO2 removal from the atmosphere, driving the Earth into a long cool period with ice cover at the poles.
Reconstructing atmospheric CO2 levels in the geological past is difficult and has previously relied on proxies that also depend on parameters that had to be assumed. Climate scientists agree that CO2 plays a crucial role in shaping Earth’s climate both today and in the past. Therefore, a grand challenge for Earth scientist is to understand what has controlled the abundance CO2 in the atmosphere.
Read more at University of Nottingham
Image: Courtesy of M.A.R Harding