1.
One problem is that we are heavily dependent upon fossil fuels. And that's where the greenhouse gases come from, by and large, some deforestation, as well. But we have not yet come to grips with how to change that. So that's where we are right now.
Richard Harris
2.
Solar and wind are now cheaper in many places than some fossil fuels and within the next two years, three, four, five years at the most. What the exponential curve does isn't going to go away. It is totally over for fossil fuels and nuclear. Nuclear's actually gone out.
Jeremy Rifkin