Earth's Atmosphere Is Losing Oxygen at an Accelerated Rate, Study Says

By Pam Wright

September 26 2016 04:45 PM EDT

Princeton University researchers used ice cores collected in Greenland to study 800,000 years of atmospheric oxygen
(Image source: Stolper, et al.)

At a Glance

  • Researchers studying the ice core in the Antarctic and Greenland say Earth is steadily losing oxygen.
  • The pace seems to have accelerated over the past century and is being blamed on fossil fuels.

Oxygen levels in the Earth's atmosphere are on a downward spiral, but it's nothing to panic over just yet, researchers say. 

In a study published in the journal Science, a team of scientists, led by researchers from Princeton University in New Jersey, tested the concentration of oxygen in the atmosphere and found that levels have dropped by almost 0.7 percent over the past 800,000 years, compared to modern levels.

More disturbing, the rate seems to have sped up over the past century, dropping by a further 0.1 percent.

Although oxygen levels do seem to be decreasing faster, the decrease is nothing to panic over, the researchers say. 

Oxygen levels fluctuate from time to time but are currently registering at around 21 percent. In the course of the 4.3 billion-year history of Earth, there have been two major spikes in oxygen levels linked to explosions of life.


To sample the ancient atmosphere, the scientists studied  bubbles of gas containing oxygen frozen in the ice of Greenland and Antarctica thousands of years ago, according to

The scientists were able to compare concentrations of oxygen and nitrogen through the millennia to show a subtle declining trend over thousands of years.

While the longer-term decrease in oxygen levels is more difficult to pin down, researchers blame the use of fossil fuels and the amount of carbon dioxide that has been released into the atmosphere for the more rapid increase over the past century.

Weathering of Silicate Rocks For Long-Term Climate Change

It is widely accepted that weathering of silicate rocks, which involves a chemical reaction between the atmosphere and the rocks over millions of years, can control long-term climate change. 

(PHOTOS: Climate Change and Greenland: Where Ice Melt Could Raise Seas by 23 Feet)

Although carbon dioxide levels have remained constant over thousands of years, scientists believe that as temperatures rise due to higher carbon dioxide in the atmosphere, silicate-weathering rates increase and remove oxygen from the atmosphere faster.

“The oxygen record is telling us there’s also a change in the amount of carbon dioxide (that was created when oxygen was removed) entering the atmosphere and ocean,” said co-author John Higgins. “The Earth can take care of extra carbon dioxide when it has hundreds of thousands or millions of years to get its act together. In contrast, humankind is releasing carbon dioxide today so quickly that silicate weathering can’t possibly respond fast enough.”

“The Earth has these long processes that humankind has short-circuited,” he added.

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