mar 26, 800000000 - Multicellular life dies out

Description:

Carbon dioxide levels fall to the point at which C4 photosynthesis is no longer possible. Free oxygen and ozone disappear from the atmosphere. Multicellular life dies out.

Planetary engineering can also be applied to keep habitability of Earth in the far future. The rate of weathering of silicate minerals will increase as rising temperatures speed up chemical processes. This in turn will decrease the level of carbon dioxide in the atmosphere, as these weathering processes convert carbon dioxide gas into solid carbonates. Within the next 600 million years from the present, the concentration of CO2 will fall below the critical threshold needed to sustain C3 photosynthesis: about 50 parts per million. At this point, trees and forests in their current forms will no longer be able to survive. Unlike other animal species, humankind has the potential ability to prolong the habitability of the planet earth by extracting and reinjecting inert carbon trapped underground back into the biosphere.