Here is a excellent link that offers information about the energy waste caused by producing so many plastic bags. Check out the sections under Other Facts **Why paper is no better than plastic, **Impact on Oceans, **Environmental Impact.
They mention paper bags use 4 times as much energy to produce than plastic. Also, only 1-3% of all plastic bags actually get recycled, which also consumes energy to do. The impact they have on the ocean must be the worst part.