American scientists from the University of Chicago have found out the time during which our planet will retain conditions for the existence of life. According to their findings, there are about 2 billion years left until the probable end of the world. The study was published on the portal of non-peer-reviewed scientific materials arXiv.
The habitability of the Earth depends on the Sun. As previous studies have shown, the star will gradually increase in luminosity over the next billion years. This is due to the compaction of its core as it converts hydrogen into helium.
Any increase in the Sun's luminosity can have a profound effect on Earth. Ecological cycles such as the carbon, nitrogen, and phosphorus cycles support the planet's biosphere. As the Sun becomes brighter, it begins to influence these processes, including the carbonate-silicate cycle, which curbs the buildup of carbon dioxide in the atmosphere.
The sun was expected to break this cycle over the next billion years, causing carbon dioxide levels to drop. Since plants depend on carbon, a sharp drop would mean complex life on land would cease to exist.
But new computer modelling suggests that carbon levels in the Earth's atmosphere will remain suitable for plants for the next 1.6 to 1.86 billion years.
After that, a transition to a humid and hot greenhouse climate should occur due to the heating of the planet. In the end, it is not the lack of carbon dioxide that will destroy the vegetation, but the excessively high surface temperature.
But the consequences won't end there. As Earth's upper atmosphere becomes more saturated with water vapor, the sun's ultraviolet energy will begin to split the water, carrying the hydrogen into space. The planet will irreversibly lose its water supply.
The scientists noted that their discovery points to a longer period of existence of the biosphere. This means that there should be more habitable exoplanets in the Universe than previously thought.
