Life Cycle Assessment (LCA) is a technique for assessing the potential environmental aspects and potential aspects associated with a product (or service), by

• compiling an inventory of relevant inputs and outputs,
• evaluating the potential environmental impacts associated with those inputs and outputs,
• interpreting the results of the inventory and impact phases in relation to the objectives of the study.

Background and protocol:

• Life Cycle Analysis Systems for Cities. Global Research Development Center (GRDC).  Urban Environmental Management
• Greenhoue Gas Protocol's Product and Supply Chain Standard (still in development as of June 2, 2009)

Examples:

• Six Products, Six Carbon Footprints. Wall Street Journal (Oct. 6, 2008)
• How Green Is My Orange? New York Times (Jan. 29, 2009)