Lease for life on Earth extended as study finds end of times are at least 1.84 billion years away

A study published in the Journal of Geophysical Research: Atmospheres has pushed the upper limit for complex plant life to survive on Earth by hundreds of millions of years. Previous estimates suggested that Earth's biosphere would meet its demise in about 1.35 billion years. However, three-dimensional (3D) general circulation models show that the more adaptable plants would actually be able to live for another 1.84 billion years. Older models predicted that as the Sun continues to age and brighten, global temperatures will skyrocket quickly, creating a world where plants would not be able to live.

As for the humans, we would be gone within the next few hundred million years. But scientists in the new study state that they vastly overestimated how fast the Earth will warm up for the plants. The clear timeline emerged as the new model took into consideration complex, realistic factors like atmospheric circulation and cloud behaviour.

When Sun gets older and brighter, what happens to Earth?

The study explored two extreme scenarios for Earth in the future as the Sun gets older. Our planet will need to endure weathering—the chemical process where atmospheric carbon dioxide (CO2) reacts with rainwater and rocks, locking carbon away. When this happens, the strong weathering could trigger a massive drawdown of CO2 to buffer the rising temperatures. While global temperatures will stay stable, the atmosphere will eventually run out of CO2. The plants would starve and die out in about 1.35 billion years when CO2 drops below 10 parts per million, as per older models. But the new model states that some plant life would be better at adapting to the new circumstances and could live even at 1 part per million of CO2.

Also Read: 1.8 million-year-old 'fiery' discovery in South African cave could change timeline of human history

However, the weathering could be weak as well. In this case, the gas levels will remain high, and CO2 won't be removed. The Sun will bake the planet, and in this case, the 3D model shows the climate remains tolerable for most land plants until 1.68 billion years. This thermal ceiling for all plant life could reach 1.87 billion years. The study shows that whether plants die from a lack of carbon dioxide or are roasted from extreme heat, in either case, it has a realistic window of 1.68 to 1.84 billion years before oceans evaporate.