45. What if CO2 leaks 100 or 1000 years from now?

Geological time is measured in the millions of years, not just in hundreds or thousands. The naturally occurring CO2 deposits that exist in the world – many of them in underground formations similar to the Weyburn and Midale oilfields – have remained stable and in place for tens of millions of years.

CO2 storage sites are chosen for the ways in which they are similar to these exact sorts of natural storage sites. Any likely leaks of CO2, in the long term, would be through the wellbores that human beings have drilled into these formations.

If these wellbores, or some other unforeseen feature of the storage location, cause the CO2 to leak many years after the companies and people who injected the CO2 are gone, plans are in place to assume responsibility for these storage sites and fix the problem. In 2011, for example, the Government of Alberta in Canada assumed what is called "long-term liability" for storage sites, meaning that the provincial government would be responsible for the maintenance of these sites after companies and people have come and gone.