Earth’s Plants Could Survive for Nearly 1.9 Billion More Years, New Study Finds

• Nature

For decades, scientists have tried to answer one of the most fascinating questions about our planet’s future: how long will plants continue to exist on Earth? A new study offers a far more optimistic answer than previously believed. According to research by Jacob Haqq-Misra and Eric Wolf, Earth’s vegetation could remain active for nearly 1.9 billion years before changing planetary conditions eventually make photosynthesis impossible.

This new timeline significantly revises previous estimates and provides a more comprehensive understanding of Earth’s long-term evolution. Beyond revealing the future of our own planet, the findings also offer valuable insights for the search for life on exoplanets with similar conditions.

Readers interested in learning more about the research can explore this detailed analysis of Earth’s future plant life, which explains how advanced climate models have reshaped scientists’ understanding of the planet’s biosphere.

A Much Longer Future for Earth’s Vegetation

Earlier estimates of the end of plant life relied on relatively simple models that projected the evolution of the Sun and Earth’s atmosphere. The new study, however, uses advanced three-dimensional climate models capable of simulating the complex interactions between solar radiation, the atmosphere, the oceans, and the global carbon cycle.

The results indicate that plants could continue to survive for approximately 1.84 to 1.87 billion years, depending on how Earth’s geological carbon cycle evolves. This represents a substantial extension compared with previous studies, which predicted the end of vegetation hundreds of millions of years sooner.

Although these timescales are almost impossible to comprehend from a human perspective, they are essential for understanding how long habitable planets can support complex biospheres.

The Sun Will Ultimately Drive the Change

The study concludes that the greatest challenge facing plants will not be human-caused climate change, but the natural evolution of the Sun itself.

Like every Sun-like star, our Sun gradually becomes brighter as it consumes its nuclear fuel. This increase is virtually imperceptible over the course of human civilization but becomes critically important when examined across hundreds of millions or billions of years.

As more solar energy reaches Earth, global temperatures will continue rising slowly. Eventually, the heat will reach levels that most terrestrial plant species will no longer be able to tolerate.

The researchers estimate that many plant species could begin disappearing around 1.68 billion years from now, while the near-complete extinction of Earth’s vegetation could occur close to 1.87 billion years in scenarios where extreme temperatures become the dominant limiting factor.

Carbon Dioxide Will Also Shape the Future of the Biosphere

Plant survival depends on more than temperature alone. Carbon dioxide (CO₂) is one of the essential ingredients for photosynthesis, the process through which plants produce the organic matter that supports nearly every ecosystem on Earth.

Over geological timescales, atmospheric CO₂ gradually declines because of natural processes such as the weathering of silicate rocks. These reactions remove carbon from the atmosphere and lock it into minerals, while volcanic activity slowly returns part of that carbon back into the atmosphere.

The balance between these opposing processes will determine how much carbon dioxide remains available for plants.

In one of the scenarios explored by the researchers, atmospheric CO₂ eventually falls below the threshold required for conventional photosynthesis. Under these conditions, plants using the C4 photosynthetic pathway could survive considerably longer than traditional species, delaying the global collapse of vegetation.

Not All Plants Will Respond the Same Way

One of the study’s most interesting conclusions is that plant life will not disappear simultaneously across all species.

Plants use different photosynthetic strategies. Most belong to the C3 group, which requires relatively high concentrations of atmospheric carbon dioxide.

C4 plants, however, have evolved specialized adaptations that allow them to function with much lower CO₂ levels while also tolerating higher temperatures. A third group, known as CAM plants—including many cacti, succulents, and certain orchids—is even more resilient under harsh environmental conditions.

This means that vast forests would disappear long before the most drought- and carbon-efficient species eventually became extinct.

The researchers also point out that some aquatic plants are capable of using dissolved bicarbonate when atmospheric CO₂ becomes scarce, potentially allowing isolated pockets of plant life to persist for even longer.

Evolution Could Still Change the Timeline

Although current climate models represent the best scientific predictions available today, the authors acknowledge that significant uncertainties remain when projecting events nearly two billion years into the future.

Biological evolution has repeatedly demonstrated an extraordinary capacity for adaptation. Hundreds of millions of years ago, trees, flowering plants, and many of today’s dominant species did not yet exist. Future evolutionary innovations could alter the projected timeline.

The researchers suggest that future plant species might evolve mechanisms capable of functioning with extremely low carbon dioxide concentrations or surviving temperatures far beyond those tolerated today.

They also mention, purely as a theoretical possibility, that an extremely advanced technological civilization could one day manipulate Earth’s climate to extend conditions favorable for life, although this remains entirely speculative.

The End of Plants Will Not Necessarily Mean the End of Life

The collapse of Earth’s vegetation would have devastating consequences for global ecosystems. Without plants, the primary source of oxygen production and organic matter supporting animals, insects, and most surface microorganisms would disappear.

However, life itself would not vanish entirely.

Even today, microorganisms live several kilometers beneath Earth’s surface, surviving through chemical reactions involving minerals, water, and rocks without relying on sunlight.

These underground ecosystems could continue to exist long after Earth’s surface becomes uninhabitable for plants and complex animals, extending the lifespan of the biosphere beyond the disappearance of vegetation.

Implications for the Search for Life Beyond the Solar System

The study also has important implications for astrobiology.

When astronomers search for potentially habitable planets, they must consider far more than a planet’s distance from its host star. The long-term evolution of the star, the planet’s carbon cycle, atmospheric composition, geological activity, and climate all play essential roles in determining habitability.

This research demonstrates that planetary habitability is not fixed over time. A world may remain capable of supporting life far longer than expected if its geological and atmospheric systems maintain a stable balance.

Understanding these mechanisms will help scientists more accurately identify exoplanets that could sustain complex life and estimate how long their ecosystems might remain active.

Ultimately, this research paints a more optimistic picture of Earth’s distant future. Although the Sun’s gradual brightening will eventually transform our planet into an environment hostile to vegetation, plants may still have nearly 1.9 billion years of existence ahead. This revised timeline not only expands our understanding of Earth’s biosphere but also provides valuable insights into the evolution of potentially habitable worlds throughout the universe.