[whimsicalism]

Personally I think you are underestimating evolution - we can fix carbon in other ways, but I agree life will be dramatically different.

[digging]

It isn't the poster who's developed this theory. It's a matter of chemistry. It's possible life could persist, but we don't know of chemical processes that would make it possible, so we shouldn't expect that it can.

[whimsicalism]

> we don't know of chemical processes that would make it possible

C4 carbon fixation would already last a lot longer than C3 carbon fixation. Probably some other sources of carbon that can be found.

[digging]

Er, I don't know of a chemical process that would make it possible. :)