What are some of the problems associated with a dependence on fossil fuels

The two obvious ones:
1. We are going to run out. It takes millons of years to form fossil fuels through animals dying, etc. We've used a lot in just one or two centuries.
2. CO2. Fossil fuels release carbon dioxide, contributing to global warming.

1) they're not renewable meaning we can't use them again so eventually they will run out
2)they harm the environment. Fossil fuels have to be burned to be of any use, and when they are burnt they release carbon dioxide, increasing global warming. When coal and oil is burned, sulfur dioxide is released, which contributes to acid rain.

We're going to run out.