The 2002 Environmental Sustainability Index builds on two prior works — a 2000 Pilot ESI and a 2001 ESI. One thing we have learned in the course of these successive efforts is that certain factors play a major role in determining whether or not it is possible to express data comparably across countries in a fair, meaningful way. The number of variables present in relevant data sets, the size of the country in terms of area, and the population of the country all make a difference.

Countries that fall below certain thresholds, we have found, are very difficult to compare in a fair, meaningful way to other countries. The Faroe Islands fall below each of the thresholds we set. We excluded countries below 5,000 square kilometers (Faroe Islands 1,400); countries below 100,000 population (Faroe Islands 46,000); and countries missing 28 or more variables (Faroe Islands 46).

This is not to say that we think that environmental sustainability ought to be overlooked in countries that do not meet these thresholds. To the contrary, we conclude in our report that there ought to be a major effort to measure environmental conditions more extensively and to understand cross-scale dynamics more completely.