1. Iceland
EPI score: 93.5
GDP per capita: $36,000
Population: 311,000
In the category of air pollution (effect on humans), Iceland scored 97.4, compared with 84.8 for countries of similar GDP per capita.

2. Switzerland
EPI score: 89.1
GDP per capita: $37,000
Population: 7.6 million
Switzerland scores a perfect 100 in forestry, water quality (effects on humans) and biodiversity and habitat. Like most rich, industrialized nations, its lowest scoring was in air pollution (effects on ecosystem).

3. Costa Rica
EPI score: 86.4
GDP per capita: $9,600
Population: 4.5 million
That such a relatively poor and developing country ranks third in the EPI is testament to the natural endowments of Costa Rica, with dense forests, plentiful water and abundant wildlife. With smart development, Costa Rica can avoid the standard path that growing nations take of polluting their environment, only to clean it up again once they become wealthy. Costa Rica touts its EPI ranking in ads for its tourism sector.

4. Sweden
EPI score: 86
GDP per capita: $33,400
Population: 9.1 million
Sweden has bragging rights, for the moment, among the Scandinavian states, where out-greening one another is a regional competition.

5. Norway
EPI score: 81.1
GDP per capita: $48,000
Population: 4.7 million
Norway is a nation of astonishing wealth, built on vast offshore reserves of oil and natural gas. The global warming impact of those fossil fuels is not debited from Norway’s results, rather it is recognized in the nations that burn them.