The planet survived cyanobacteria [1], which dumped vast amounts of highly toxic oxygen into the atmosphere. The planet had a mass extinction, a global freeze,

The planet survived cyanobacteria [1], which dumped vast amounts of highly toxic oxygen into the atmosphere. The planet had a mass extinction, a global freeze, but life managed to pull through (even Cyanobacteria survived). Compared to that, our addition of Carbon to the atmosphere is minuscule. To your first question, it is entirely possible to sequester carbon from the atmosphere, but it is expensive. Consider how much of GDP was put into getting the Carbon there in the first place, and that burning fossil fuels is cheaper then recovering the carbon they emitted. The most promising solution I have heard is to take an organic approach. Instead of sequestering it ourselves, engineer the planet to do it for us. For example, we can dump nutrients into largely dead regions of the ocean stimulating photosynthesis, and let the carbon fall to the bottom (as a solid). [1]http://en.wikipedia.org/wiki/Cyanobacteria#Earth_history http://en.wikipedia.org/wiki/Cyanobacteria#Earth_history