Before you brown bag it, consider these environmental disadvantages of paper: Causes pollution: Paper production emits air pollution, specifically 70 percent more pollution than the production of plastic bags [source: Thompson]. According to certain studies, manufacturing paper emits 80 percent more greenhouse gases [source: Lilienfield]. And, consider that making paper uses trees that, instead, could be absorbing carbon dioxide. The paper bag making process also results in 50 times more water pollutants than making plastic bags [source: Thompson].
Consumes energy: Even though petroleum goes into making plastic, it turns out that making a paper bag consumes four times as much energy as making a plastic bag, meaning making paper consumes a good deal of fuel [source: reusablebags.com].
Consumes water: The production of paper bags uses three times the amount of water it takes to make plastic bags [source: Lilienfield].
Inefficient recycling: The process of recycling paper can be inefficient -- often consuming more fuel than it would take to make a new bag [source: Milstein]. In addition, it takes about 91 percent more energy to recycle a pound of paper than a pound of plastic [source: reusablebags.com].
Produces waste: According to some measures, paper bags generate 80 percent more solid waste [source: Lilienfield].
Biodegrading difficulties: Surprisingly, the EPA has stated that in landfills, paper doesn't degrade all that much faster than plastics [source: Lilienfield].
I'm sorry, but if you weight the advantages/disadvantages, paper LOSES big time. I don't think there is any contest.