Recycling revisited-life cycle comparisons of global warming impact and total energy use of waste management strategies

Recycling of waste materials has been analysed from a life cycle perspective in a number of studies over the past 10-15 years. Publications comparing the global warming impact and total energy use of recycling versus incineration and landfilling were reviewed in order to find out to what extent they agree or contradict each other, and whether there are generally applicable conclusions to be drawn when certain key factors are considered. Four key factors with a significant influence on the ranking between recycling, incineration, and landfilling were identified. Producing materials from recycled resources is often, but not always, less energy intensive and causes less global warming impact than from virgin resources. For non-renewable materials the savings are of such a magnitude, that apparently the only really crucial factor is what material is replaced. For paper products, however, the savings of recycling are much smaller. The ranking between recycling and incineration of paper is sensitive to for instance paper quality, energy source avoided by incineration, and energy source at the mill.