Plastics made from petroleum, such as polyethylene, have a
well-defined life cycle. When landfilled, the carbon in the plastic
will be sequestered and not contribute to global warming. Recycled
polyethylene may contribute even less fossil CO2 to the environment
if less energy is used to recycle it than is used to make it in the
first place. In these cases, conventional plastics may have less
impact on GHG emissions that those designed to biodegrade