I think many people exaggerate the effects of global warming. How do we know that the recent increase in temperature isn't just some trend? In the early 20th century, there were crude reports of somewhat elevated temperatures. For all we know, "global warming" could just be caused by a century-long trend in solar activity, like sun spots.
In respect to fossil fuels, you can't just snap your finger and say "We're not going to use fossil fuels anymore." Do you know how many appliances, services and industries rely on fossil fuels? The only other energy source that's anywhere near as cost-efficient is nuclear power, and too many people are wary of that - there hasn't been a single nuclear plant built in the U.S. for the last twenty-some years. Nothing else comes close. Even if there were another efficient source, making such a change to the economy would be a long, gradual process, which could take decades. Trust me, fossil fuels aren't leaving any time soon.
