It is said that Alberta, Canada, has more oil in its oil sands than does Saudi Arabia, and many estimate that the methane resources available in continental shelf clathrate formations are more than...

It is said that Alberta, Canada, has more oil in its oil sands than does Saudi Arabia, and many estimate that the methane resources available in continental shelf clathrate formations are more than all other hydrocarbon resources—oil, coal, and natural gas—put together. Assuming these are reasonable first estimates of resource availability, why is anyone worried about fossil fuel use?