A DRAMATIC drop in Earth’s oxygen levels will eventually kill off most life on Earth, according to a new study.
Scientists think life as we know it could have about a billion years left before a ‘mass suffocation’ event sets in.
A dramatic reduction in oxygen would mean Earth would lose its ozone layer and could lose its oceans to increased radiation from spaceCredit: Alamy
Earth’s atmosphere is currently about 21% oxygen, an element that’s crucial to support the life of large complex animals like us.
Scientists know Earth’s oxygen levels weren’t always as high and suspect a dramatic decrease will happen again in the future.
This was the focus of research by two scientists from Japan and the US.
Kazumi Ozaki and Chris Reinhard created a model of Earth and its natural systems so they could predict how our planet will change.
This artist’s impression shows what a dead planet Earth may look like compared to the version we know that’s full of lifeCredit: Alamy
Their work is part of a NASA project that’s looking into planet habitability.
Ozaki, a scientist at Toho University in Funabashi, Japan, told New Scientist: “We find that the Earth’s oxygenated atmosphere will not be a permanent feature.”
The good news is the researchers think Earth will maintain high oxygen levels for about another billion years.
After this, the Earth could return to a state it’s thought to have been in around 2.4 billion years ago before something called the Great Oxidation Event took place.
The scientists claim that as the Sun ages, it will release more energy and become much hotter.
They think this will dramatically reduce the amount of carbon dioxide in our atmosphere as CO2 would absorb the heat and breakdown.
We’re used to thinking of too much CO2 as bad for the environment but the planet needs some so that plants and photosynthesising organisms can absorb it and turn it into oxygen.
Very low CO2 would means things like plants would die and this would lead to a severe lack of oxygen.
Reinhard, a scientist at the Georgia Institute of Technology in Atlanta, told New Scientist: “The drop in oxygen is very, very extreme – we’re talking around a million times less oxygen than there is today.”
The researchers also think methane levels will be 10,000 times higher than they are today.
They suspect Earth would take around 10,000 years to lose its oxygen.
All animals and most life would die out apart from primitive bacteria that don’t require oxygen.
Earth would also lose its ozone layer, leaving it exposed to more heat from the Sun and harmful radiation.
Intense radiation could wipe the oceans off the planet.
All this may seem a very long time away but scientists it could have implications for how we’re searching for life on other planets.
The study suggests searching for signs of oxygen when looking for potentially habitable planets or life out in space may be restrictive and we could emphasise the importance of other elements instead.
The full study has been published in the journal Nature Geoscience.
The Sun – all the facts you need to know
What is it, why does it exist, and why is it so hot all the time?
The Sun is a huge star that lives at the centre of our solar system
It’s a nearly perfect sphere of hot plasma, and provides most of the energy for life on Earth
It measures a staggering 865,000 miles across – making it 109 times bigger than Earth
But its weight is 330,000 times that of Earth, and accounts for almost all of the mass in the Solar System
The Sun is mostly made up of hydrogen (73%), helium (25%) and then a number of other elements like oxygen, carbon and iron
Its surface temperature is around 5,505C
Scientists describe the Sun as being “middle-aged”
The Sun formed 4.6billion years ago, and it’s been in its current state for around four billion years
It’s expected that it will remain stable for another five billion years
It doesn’t have enough mass to explode as a supernova
Instead, we expect it to turn a hulking red giant
During this phase, it will be so big that it will engulf Mercury, Venus and Earth
Eventually it will turn into an incredibly hot white dwarf, and will stay that way for trillions of years
In other news, the world’s first space hotel will open its doors to cash-flushed guests from 2027.
A Japanese billionaire has launched a search for eight people to join him as the first private passengers on a trip around the moon with Elon Musk’s SpaceX.
And, Nasa has unveiled a new lunar lander that could put astronauts back on the Moon in 2024.
What do you think of the oxygen drop theory? Let us know in the comments…
We pay for your stories! Do you have a story for The Sun Online Tech & Science team? Email us at [email protected]