Don't worry, but scientists have discovered that oxygen is very gently draining out of Earth's atmosphere, and presently, they are not sure why. By analyzing air bubbles stuck inside ice cores from Greenland and Antarctica, a team from Princeton University has found oxygen levels have dropped by 0.7% in the last 800,000 years, and the team is still figuring out why this could be critical to predicting Earth's future. Getting the answer is not going to be easy, however, oxygen on our planet is continuously being recycled by human beings, animals, plants, and even silicate rock. Currently, ice cores are among the finest ways we have of getting permanent readings of how much oxygen is present.
Scientist Daniel Stolper told Maddie Stone at Gizmodo, "We did this study more out of interest than any expectation. We did not know whether oxygen would be going up, down, or flat. It turns out there is a very clear drift."
As much as ecosystems on Earth are disturbed, the decrease is only a slight one, but it can still tell us more about the mysteries of what makes planet fit to live in, valuable information to have if we are ever going to live on Mars. An increase in erosion rates is one theory behind the oxygen descent; more erosion would leave and oxidize more fresh sediment, dropping atmospheric oxygen levels.
Another thinkable cause is long-term climate change, over the last few million years; we've seen a slight overall drop in global temperatures, even though Earth has been rapidly heating up over the past half a century. But before we started burning huge amounts of fossil fuels after the industrial revolution, the ocean was very sluggishly cooling, and that could have started an ecological chain reaction where it started consuming more oxygen out of the atmosphere.
For now, though, these are only theories that need further testing.
For the first few billion years of its life, Earth's atmosphere did not have any oxygen in it whatsoever. Researchers consider small algae called cyanobacteria evolved and activated a quick rise in oxygen levels and, afterward, in the number of animals who could breathe it in. Today, around 21% of the air we breathe is consisting of oxygen, alongside nitrogen, argon, and carbon dioxide.
While its effects on the atmosphere are not as serious as carbon dioxide, it does have an influence on the amount of sunlight that touches the ground, and there is a sign that varying oxygen levels have affected Earth's climate in the past. While the amount of oxygen drop is nothing to worry about just so far, Stolper does have a warning about the most recent 200 years since the industrial revolution started; information which is not involved in the new report.
He told Gizmodo, "We are consuming O2 at a rate a factor of a 1000 times faster than before. Humankind has totally short-circuited the sequence by burning tonnes of carbon... it is yet another sign of our collective capacity to do what happens naturally on the Earth, yet so much faster."
The study has been originally written in Science.