Re: Really?
It won't be at atmospheric temperature and pressure. Otherwise, these people wouldn't be publishing this paper but setting a company for CCS (carbon capture and sequestration) having solved the CO2 problem.
They'll need to demonstrate the necessary conditions (pressure and temperature and possibly catalyst) to proceed, and that these could be found in volcanoes, but I remain sceptical. We do know that geological events have indeed had a significant effect on life on earth – the great extinction for example – but this does have something of a rabbit and a hat about it. Quite possibly there was, or were, several events that contributed to the tipping point for a massive expansion of cyanobacteria and photosynthesis.
But it's still an interesting contribution to the debate.