This makes it difficult to fully assess the impact the fossil fuel industry has had on oxygen levels.
“There was no consensus on whether the oxygen cycle before humankind began burning fossil fuels was in or out of balance and, if so, whether it was increasing or decreasing,” says Stolper, according to Live Science.
Gaining a better understanding of how oxygen levels have fluctuated on Earth throughout history would provide crucial information about the development of life on Earth and the implications of climate change.
“Atmospheric oxygen levels are fundamentally linked to the evolution of life on Earth, as well as changes in geochemical cycles related to climate variations,” Charles Q. Choi of Live Science explains. “As such, scientists have long sought to reconstruct how atmospheric oxygen levels fluctuated in the past, and what might control these shifts.”