As much as Cuba's economy is nothing to aspire to, the WWF says that they're the only country on earth that has undergone sustainable development. That is, the have the 2nd highest HDI in Latin America and they've managed to achieve it with a sustainable ecological footprint. Of course, this doesn't outweigh the fact that people on the island have very little freedom, but it does say something about the power of central planning in developing economies that don't destroy the planet.
What? Cuba kept a sustainable ecological footprint because its economy, with the embargo and collapse of the Soviet Union, just couldn't afford industrialization.
http://assets.panda.org/downloads/living_planet_report.pdf