London:
Armageddon! All animal and plant life may vanish from the Earth within the next one billion years, a new study has predicted.
However, ironically the end of the world is going to arrive as a result of too little carbon dioxide in the atmosphere, rather than too much of the gas, researchers say.
According to the study by astrobiologist Jack O'Malley James of the University of St Andrews, within the next billion years, increased evaporation rates and chemical reactions with rainwater will draw more and more carbon dioxide from the Earth's atmosphere.
The falling levels of CO2 will lead to the disappearance of plants and animals and our home planet will become a world of microbes.
At the same time the Earth will be depleted of oxygen and will be drying out as the rising temperatures lead to the evaporation of the oceans. A billion years after that the oceans will have gone completely, researchers said.
The main driver for these changes will be the Sun. As it ages over the next few billion years, the Sun will remain stable but become steadily more luminous, increasing the intensity of its heat felt on Earth and warming the planet to such an extent that the oceans evaporate.
"The far-future Earth will be very hostile to life by this point. All living things require liquid water, so any remaining life will be restricted to pockets of liquid water, perhaps at cooler, higher altitudes or in caves or underground," said O'Malley-James.
This life will need to cope with many extremes like high temperatures and intense ultraviolet radiation and only a few microbial species known on Earth today could cope with this.
In his new work, O'Malley James has created a computer model to simulate these extremely long-range temperature forecasts and has used the results to predict the time-line of future extinctions.
The new model not only tells us a lot about our own planet's future, but it can also help us to recognise other inhabited planets that may be approaching the end of their habitable lifetimes.
"When we think about what to look for in the search for life beyond Earth our thoughts are largely constrained by life as we know it today, which leaves behind telltale fingerprints in our atmosphere like oxygen and ozone. Life in the Earth's far future will be very different to this, which means, to detect life like this on other planets we need to search for a whole new set of clues," O'Malley-James added.
O'Malley-James made his bleak forecast at the National Astronomy Meeting at the University of St Andrews, Scotland.
