PDCA

An Environmental Management System within an organization
is one that follows the well-known Quality Management approach
of "Plan, Do, Check, Improve." It is a problem identification
and problem solving tool which can be implemented in many
different ways depending on the precise sector or activity
and the needs perceived by management.

http://www.unep.or.jp/ietc/Publications/TechPublications/
TechPub-14/1-EMS1.asp