Our dependency on them must be decreased, in order to sustain them for the future.
If we talk about reducing our dependence on fossil fuels, then this is the same as requiring enormous research and development. However, I highly doubt it can diminish in a short amount of time. It takes an extra approach and a very long time to change the people's habits that have taken root. If fossil materials are replaced, the solution is electricity, but electricity also requires coal for its basic material.