A study highlighted in Astrobiology estimates Earth will stop being habitable in 1.75 to 3.25 billion years, when the planet moves out of the Sun’s habitable zone.
Stellar evolution models point to the Sun’s steadily rising luminosity as the driver, pushing Earth toward a Runaway greenhouse effect that would evaporate the oceans and permanently erase liquid water.
Complex life would likely vanish well before that final deadline, with only hardier microorganisms potentially surviving in isolated niches until conditions become terminal.
The work also frames habitability beyond Earth: Mars could remain in the Sun’s habitable zone for about 6 billion years, while some exoplanets around smaller stars may stay viable far longer.
Could future planetary engineering save Earth, making interstellar escape an unnecessary gamble for humanity's survival?
How can new agnostic methods finally confirm alien life when traditional chemical signatures on distant worlds remain ambiguous?
With messages arriving at Gliese 581 soon, what protocols exist if we actually receive a reply from an alien intelligence?
How Long Will Earth Remain Habitable? New Models Push Timeline for Complex Life to 1.6–1.86 Billion Years
Overview
Recent research has greatly extended our understanding of how long Earth can support complex life. Early estimates in 1982 suggested only 100 million years remained, but by 1992, improved climate models pushed this to up to 1.5 billion years. In 2024, Graham and collaborators made two key advances: they found that plants can survive at much lower CO2 levels than previously thought, and that rock weathering depends less on temperature. These changes mean Earth's biosphere could last up to 1.86 billion more years, with heat—not CO2 shortage—becoming the main limit for life in the distant future.