The term carbon foot print is used to indicate how much carbon dioxide is created in a said activity. (answers.com)
The design philosophy has been to treat the waste water as a resource from which water and energy can be recovered in addition to reducing the site's carbon foot print. (cstwastewater.com)
The Lopez Community Land Trust built Common Ground as «a testament to living comfortably and sustainably with a greatly reduced carbon foot print.» (treehugger.com)