1. Iceland

2. Switzerland

3. Costa Rica

4. Sweden

5. Norway

And the US?

According to a global environmental performance index presented today at the annual economic forum in Davos, Switzerland, the United States fell 22 places to 61st.

Compiled biannually by Yale and Columbia University researchers, the 2010 Environment Performance Index ranks Iceland the greenest country in the world for reducing carbon emissions and planting new forests, along with plentiful hydropower and geothermal energy.

Sierra Leone places last on the 163-country list, behind fellow African developing countries Niger, Togo, Angola, Mauritania, and the Central African Republic.