Earth Continues To Lose Oxygen, And Scientists Are Stumped

Darien Cavanaugh

The oxygen levels on earth continue to drop, and scientists are struggling to find an explanation. There's no cause for alarm yet, as the steady decline has been going on for roughly 800,000 years.

However, a new study on the phenomenon conducted by Princeton University researchers is creating considerable interest within the scientific community and raising questions about the possible effects of fossil fuel usage, according to a report from Gizmodo.

"We did this analysis more out of interest than any expectation," Daniel Stolper, a Princeton University geochemist and lead author of the study, told Gizmodo. "We didn't know whether oxygen would be going up, down, or flat. It turns out there is a very clear trend."

The researches estimated that the atmospheric oxygen levels on earth have dropped by approximately 0.7 percent during the past 800,000 years, but they're not certain about how steady the levels were prior to that.

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"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."

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"To put it in perspective, the pressure in the atmosphere declines with elevation. A 0.7 percent decline in the atmospheric pressure of oxygen occurs at about 100 meters (330 feet) above sea level — that is, about the 30th floor of a tall building" Stopler told Live Science.

Stolper explained that there are two prevailing theories on what might be causing the decline.

"The first is that global erosion rates may have increased over the past few to tens of millions of years due to, among other things, the growth of glaciers — glaciers grind rock, thereby increasing erosion rates. Alternatively, when the ocean cools, as it has done over the past 15 million years, before fossil fuel burning, the solubility of oxygen in the ocean increases. That is, the oceans can store more oxygen at colder temperatures for a given concentration of oxygen in the atmosphere."

There is also some "leakage" as oxygen is converted into water and back.

"Every thousand years or so, all of the O2 [in our atmosphere] is turned into water and then back into O2," Stolper told Gizmodo. "But there's an ever so slight leak over time, in terms of extra production or consumption."

The researches examined air trapped in ancient polar ice samples from Greenland and Antarctica to get their results, according to Live Science.

One unexpected result of the research is the discovery that while oxygen levels have changed, carbon dioxide levels appear to have remained steady.

"At first glance, these two sets of observations, both from gases trapped in ice cores, are paradoxical," John Higgins, a Princeton geochemist and senior author of the study, told Live Science.

If oxygen levels on Earth continue to decline at their current rate, it would still take a considerable amount of time for it to cause any significant effects to life on Earth. It's nothing to worry about now, but millions of years from now it might be a different story.

[Featured Image by Getty Images]