Carbon Dioxide has never been the danger. It has been methane and land use that has been the majority of humanity's effect on the climate. Cutting down forest, building cities and suburbs, etc. have had significantly more effect than carbon dioxide, and will continue to do so. Meat animal herds (cows) probably have more effect than carbon dioxide.In fact the use of bio-fuels will have a negative effect on the climate. The only real answer in the long run is nuclear and geothermal power. This is not to suggest that carbon dioxide has no effect, just that our money and time is better spent elsewhere. The majority of the solar warming over the last 30 years correlates best with increases in solar radiation, but that which does not correlates as much with land development and increasing meat production as with atmospheric carbon dioxide.

It does not matter about the costs, because even if it were 100% efficient it would require huge tracks of land to replace our current energy sources. That in itself would be more damaging to the environment than the current fossil fuel problems. Only Geothermal and nuclear power offer environmentally sound approaches to replacing fossil fuel.