Plant life on Earth is projected to end in about 1.8 billion years, according to a new study by researchers from the University of Colorado Boulder and Blue Marble Space. The demise of vegetation is attributed to the Sun's gradual brightening, which will raise Earth's temperatures beyond the tolerance of most plants, and a decrease in atmospheric carbon dioxide, a vital component for photosynthesis.
The study utilized a three-dimensional computational climate model to simulate future climate scenarios on Earth, considering both increasing solar radiation and falling carbon dioxide levels. Previous estimates for the lifespan of Earth's biosphere have been shorter, but this model accounted for a more comprehensive range of environmental factors, including temperature, clouds, rainfall, oceans, and atmospheric circulation.
Researchers explored two primary scenarios: one where carbon dioxide steadily decreases as it is absorbed by rocks, and another where it remains relatively constant while the planet simply heats up. In both scenarios, rising temperatures and a scarcity of carbon dioxide will eventually make large-scale plant survival impossible. The study suggests that hardy plants, such as cacti and those with specialized photosynthetic pathways, might be the last to survive, clinging on until Earth eventually loses its oceans.
The modeling did not account for potential evolutionary changes in plant life or hypothetical technological advancements by humans, which could extend the survival of vegetation. The researchers noted that plants might evolve to regulate their own temperature and pressure or adapt to aerial environments, potentially dispersing to higher altitudes or even other celestial bodies.
For context, the Sun is expected to become a red giant star in about five billion years, expanding to more than a hundred times its current size. This stellar evolution will drastically alter the solar system, likely destroying all life on Earth. The fate of Earth's rocky core after this metamorphosis remains uncertain.
