Fossil fuels can be replaced and should be used by mankind for the energy we need. Fossil fuels are replaced everyday by organic things dying. It would be foolish for us not to use the fossil fuels for a major source of our energy needs until a better, more reliable source can be found.
No, fossil fuels can not be easily replaced, because our current dependency and usage is entirely to high. At this point, almost everything runs on fossil fuels, and to switch them all over or replace them will take money, technology, and time. It is a slow and stead pace to get rid of fossil fuels and can be seen every year as it advances.
No, fossil fuels cannot be easily replaced, because we have already spent a great deal of time and energy working on alternatives, but nothing seems to be forthcoming that is as inexpensive, easy to produce, and as efficient as fossil fuels. It's possible that fossil fuels can be replaced, but the answer does not appear to be easy.
Fossil fuels cannot be easily replaced. This is because the energy systems in the United States are so used to relying on big oil. Machines, home heating, gas, and more all rely on old-fashioned fossil fuels. It will have to be a slow conversion away from oil/petrol for us to become less reliant on it.
No, I do not believe fossil fuels can be easily replaced. We've started the process, but at this point its taken a lot of time to simply get as far as we have. Part of the problems, is obviously created by markets and the fact that these markets have been fixed to continually use fossil fuels so the countries that produce them can benefit. This is counter intuitive to what is actually best for the world, and it has made the replacement of fossil fuels even more difficult than it should be.