500-600 million years: The Sun's increasing luminosity begins to disrupt the carbonate–silicate cycle; higher luminosity increases weathering of surface rocks, which traps carbon dioxide in the ground as carbonate. As water evaporates from the Earth's surface, rocks harden, causing plate tectonics to slow and eventually stop once the oceans evaporate completely. With less volcanism to recycle carbon into the Earth's atmosphere, carbon dioxide levels begin to fall. By this time, carbon dioxide levels will fall to the point at which C3 photosynthesis is no longer possible. All plants that use C3 photosynthesis (≈99 percent of present-day species) will die.
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800-900 million years: Carbon dioxide levels will fall to the point at which C4 photosynthesis is no longer possible. Without plant life to recycle oxygen in the atmosphere, free oxygen and the ozone layer will disappear from the atmosphere allowing for intense levels of deadly UV light to reach the surface. Animals in food chains that were dependent on live plants will disappear shortly afterward. At most, animal life could survive about 3 to 100 million years after plant life dies out. Just like plants, the extinction of animals will likely coincide with the loss of plants. It will start with large animals, then smaller animals and flying creatures, then amphibians, followed by reptiles, and finally, invertebrates. In the book The Life and Death of Planet Earth, authors Peter D. Ward and Donald Brownlee state that some animal life may be able to survive in the oceans. Eventually, however, all multicellular life will die out.
https://en.wikipedia.org/wiki/Timeline_of_the_far_future#Ear...
500-600 million years: The Sun's increasing luminosity begins to disrupt the carbonate–silicate cycle; higher luminosity increases weathering of surface rocks, which traps carbon dioxide in the ground as carbonate. As water evaporates from the Earth's surface, rocks harden, causing plate tectonics to slow and eventually stop once the oceans evaporate completely. With less volcanism to recycle carbon into the Earth's atmosphere, carbon dioxide levels begin to fall. By this time, carbon dioxide levels will fall to the point at which C3 photosynthesis is no longer possible. All plants that use C3 photosynthesis (≈99 percent of present-day species) will die.
...
800-900 million years: Carbon dioxide levels will fall to the point at which C4 photosynthesis is no longer possible. Without plant life to recycle oxygen in the atmosphere, free oxygen and the ozone layer will disappear from the atmosphere allowing for intense levels of deadly UV light to reach the surface. Animals in food chains that were dependent on live plants will disappear shortly afterward. At most, animal life could survive about 3 to 100 million years after plant life dies out. Just like plants, the extinction of animals will likely coincide with the loss of plants. It will start with large animals, then smaller animals and flying creatures, then amphibians, followed by reptiles, and finally, invertebrates. In the book The Life and Death of Planet Earth, authors Peter D. Ward and Donald Brownlee state that some animal life may be able to survive in the oceans. Eventually, however, all multicellular life will die out.