Storing CO2 down at the bottom of the ocean is also another troubling thought. We know the ocean bottom is not inactive and sometimes volcanos do erupt down under. We don't hear it or see it but it happens more frequently than you think it would. A major volcano right nearby a storage spot would push up all the CO2 we dumped over the years almost instantly. This rapid change of the atmospheric CO2 concentration is worse than gradual but balanced increase. There simply won't be any time for the nature to adapt.
Storing CO2 in an empty oil or gas well may be OK. The fact that an earthly hole held gas in it for a long time may sound safe to store whole bunch more in there. There is a catch though. While hydrocarbons (methane, ethane, etc.) are neutral, CO2 is not. Carbon dioxide is acidic! It can dissolve the minerals down there and make its way out from somewhere. Without studying the chemical composition of the oil or gas well, I'm stringently opposing a stuff-it-all-down-in-the-oil-wells option.
To me, the only viable option to get rid of CO2, mr. green house gas, is to create market for CO2. A CO2 economy, in other words, would drive the need to capture and utilize CO2 as permanent or recyclable material. There are issues with this too, however. One, the CO2 using industry (such as beverages, fertilizers) is not big enough to recycle all the exhaust CO2 that comes out of the coal power plants. Only 0.8 % (data from 1989) of all CO2 emissions could be accounted for. Even if we converted all the CO2 back to the fuels (i.e. hydrocarbon based) we can only claim 60 % of all emissions. We are in deep trouble my friend. Two, how can we make sure all the CO2 used in this market is recycled (not produced)?.
As many global warming activists would point out, there's not a single magic bullet to solve CO2 crisis. One thing I should make clear is that if you are a believer of global warming or not, it is extremely unhealthy for the earth to have so high Image by guano via Flickrconcentrations of CO2. The crops aren't going to double with increasing CO2, the heat waves will shift climates and water resources, and make the global crop production unstable causing all kinds of violence and hunger. So, the solution lies on implementing many working solutions not on collecting Nobel prizes. All should come together to make a difference: Conservation, alternative fuels and a CO2 economy with new products that use -only- recycled CO2.