Developed by the Earth Institute and Yale's School of Environment, while widely used by The World Economic Forum, the Environmental Performance Index (EPI, image at right) is the most meaningful set of criteria and system for ranking a countries "green" factor. In 2010, the countries ranking 1st, 2nd and 3rd were Iceland, Switzerland and Costa Rica, respectively. The United States ranked 61st. Used by policy makers and environmental scientists as a benchmark index, the EPI has two general objectives; quantify leading indicators that affect:
i) environmental health
ii) environmental vitality.
Each objective has multiple indicators. Some examples of indicators for environmental health are adequate sanitation, drinking water, and urban particulates. Indicators for environmental vitality include things like irrigation stress, pesticide regulation, industrial carbon intensity and emissions per capita. To measure a countries EPI, indicator outputs are quantified and reported as metrics. Costa Rica's favorable EPI ranking is certainly due to a national commitment of being carbon neutral and environmentally progressive.
