A Billion Years From Now The Earth Will Look Very Different

The very distant future, about a billion years from now, scientists say the atmosphere of Earth will contain very little oxygen. That will make the planet uninhabitable for complex aerobic life. Today, our atmosphere is about 21 percent oxygen, and that oxygen-rich nature makes it ideal for large and complex organisms like people.

In Earth's distant past, the planet had much lower oxygen levels, and scientists believe similarly low oxygen levels are possible in the distant future. Researchers Kazumi Ozaki from Toho University and Chris Reinhard from the Georgia Institute of Technology have modeled the climatic, biological, and geological systems of Earth to learn how conditions will change in the future. Their research has found that Earth's atmosphere will have high levels of oxygen for the next billion years before dramatically returning to low levels similar to what existed prior to an event known as the Great Oxidation Event that occurred about 2.4 billion years ago.

The researchers say they have found the oxygen-rich atmosphere of our planet is not a permanent feature. One major reason they expect the shift in oxygen levels is that as the sun ages, it becomes hotter and releases more energy. That is expected to drive a decrease in the amount of carbon dioxide in the atmosphere as it absorbs heat and breaks down.

Calculations estimate that within a billion years, Earth's carbon dioxide level will become so low that photosynthesizing organisms such as plants won't be able to survive to produce oxygen. The mass extinction of photosynthetic organisms will be the primary driver of the massive oxygen reduction on the planet.

Reinhard believes the drop in oxygen will be extreme at around a million times less oxygen on the planet than there is today. Simultaneously, methane levels will increase dramatically to the tune of about 10,000 times the amount of methane that we have in the atmosphere today. The change from oxygen-rich to oxygen-poor is believed to occur over about 10,000 years.