We use most plastic bags for just minutes, but they take 15 to 1000 years to break down. Besides landfill space, they're responsible for animal deaths, litter and growing continents of floating marine garbage, not to mention the fact that most are made from petroleum. In 2002, Ireland levied a 15 cent tax on plastic bags (a plastax), subsequently reducing their use by 90%.

Now countries like China and Australia and cities like San Francisco are implementing bans. We stopped in on tiny Coles Bay, Tasmania (Australia) where residents, anxious to protect migrating whales and their local national park, banned plastic bags back in 2003.