This is a sufficiently influential issue that environment-centric procurement (green procurement) is sometimes seen to stand alone from sustainable procurement. The most straightforward justification for green procurement is as a tool with which to address climate change, but it offers the broader capacity to mitigate over-exploitation of any and all scarce resources. Green procurement introduces into the procurement process a comparison between alternatives based on the criterion of their environmental impact. This comparison is extended to all stages of the procurement process, from the design stage, to the tender evaluation and realization stages.