The voluntary Carbon Standard provides a global standard and program for approval of credible voluntary offsets.

"VCS offsets must be real (have happened), additional (beyond business-as-usual activities), measurable, permanent (not temporarily displace emissions), independently verified and unique (not used more than once to offset emissions)." (Source: v-c-s.org)

Developed by The Climate Group, the International Emissions Trading Association (IETA), and the World Business Council for Sustainable Development (WBCSD).