Argument: C02 would leak too slowly (thousands of years) to be a concern
Richard Van Norden. "Carbon storage – what will the great-great-(...)-great-great grandchildren think?" The Great Beyond. June 28, 2010: "Shaffer calculates, if the leakage rate is 1% every 10 years, by 5000 AD mean atmosphere warming will be as bad as if no storage had been attempted. Dial that leakage rate down to 1% every 100 years, and we get to 20,000 AD before atmospheric warming is as bad as no storage at all. 20,000 AD? By this point humankind will surely be on other planets or, more likely, extinct. But Shaffer is concerned about future generations in 20,000 AD. He points out that nuclear waste management works on these timescales – tens of thousands of years. He effectively says that once we have chosen to release the locked-up carbon dioxide in fossil fuels such as oil and coal, even stuffing almost all of the gas underground merely postpones its eventual deleterious effect on global temperatures, ocean acidification, and other problems. Only a leakage rate below 1% over 1000 years could avert this burden on future generations, he calculates. At that rate, they get to live well past 50,000 AD before the extra heat bothers them. (The IPCC’s special report on carbon capture and storage, incidentally, concludes that the fraction of carbon dioxide retained in appropriately selected and managed geological reservoirs is ‘likely’ to exceed 99% over 1000 years. ‘Appropriately selected and managed’ is the tricky clause in that conclusion – how many stores will be inappropriately selected and managed?). I feel that this calculation adds little to the question of whether we should use carbon capture and storage right now as a way of cutting down on carbon dioxide emissions from coal. Yes, as Shaffer says, a leaky store will create delayed warming in the future. But what a comfortingly long way away that future is, in his projections. Moreover, he considers that future humans make no attempt at re-sequestering escaped carbon dioxide. And he does not suggest that today we might try both to capture carbon dioxide underground and reduce our fossil fuel emissions. And aren’t there many more pressing practical concerns about carbon capture and storage to consider right now – such as whether it works over a hundred years, not whether it works over tens of thousands of years?"