As discussions go on about climate change and with the Copenhagen Summit nearby tension is building as to what the summit could solve, whether if there will be quick decisions made and implemented.
A study by the UK Royal Society indicated that constructing engineering marvels could become the last resort and that such feats are feasible. At this point geo-engineering, engineering the environment we live in is the solution to reduce carbon dioxide emissions. Projects like using scrubbers to clean the atmosphere, or using mirrors in space to deflect the Sun's rays from entering the atmosphere.
There were talks and I think it is in the implementation stage of trapping CO2 underground. The projects suggested are technically possible already would require decades to get them up but it is feasible.