• Question: When will oxygen run out on earth, and what backup planet will humans have to live on when the world explores in 1 trillion years?

    Asked by anon-181914 on 25 Jun 2018.
    • Photo: Lauren Burns

      Lauren Burns answered on 25 Jun 2018:


      Oxygen isn’t necessarily the issue, there are lots of things we can do to stop oxygen running out (like planting trees!). What is perhaps a bigger issue, is in about 5 billion years the sun should explode (as all stars have a life span and ours is in the middle of its). If the sun explodes, it doesn’t matter what planet people are on in this solar system we’d all go down with it. Hopefully, by that point, we’ll have mastered space-travel and be able to find another planet with similar conditions that we can live on in another solar system – or even galaxy!

    • Photo: Liza Selley

      Liza Selley answered on 28 Jun 2018:


      I don’t think oxygen would run out but there are some things that could reduce the amount of oxygen that we have compared to carbon dioxide. Animals take oxygen from the air and replace it with carbon dioxide while plants do the opposite, taking carbon dioxide and replacing it with oxygen. If one of the really enormous volcanoes were to erupt, some scientists predict that it would create so much ash and vapour that sunlight would be blocked out completely for many years. Without sunlight, plants cannot live which means they cannot convert carbon dioxide to oxygen. A nuclear war would have the same effect. I think these situations would be the closest we got to running out of oxygen. However, the lack of plant based food and animal feed would be the bigger problem at the time!

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