Researchers ranked countries based on 25 indicators, including water and air quality, greenhouse gas emissions and the impact of the environment on the health of the population. (For more detail on the methodology, click here.) A score of 100 is excellent. Sierra Leone ranks at the bottom of the list with a score of 32. The U.S. ranks in the middle of the pack with 63.5. Iceland took top honors with a score of 93.5 thanks to ample clean water, lots of protected nature areas, good national health care and a plenitude of usually clean geothermal power.
Slideshow: The World's 10 Cleanest Countries
Will Eyjafjallajokull wreck Iceland's rating the next time the academics run the numbers in 2012? The answer is no. "We do not score natural disasters," says Daniel Esty, a professor of environmental law at Yale who heads up the EPI and wrote the acclaimed book Green to Gold. The index is weighted to metrics that track how governments are performing relative to environmental policy goals, such as access to adequate sanitation and water, habitat protection and industrial emissions. The amount of sulfur dioxide released from fuel usage counts, not what's put out by volcanoes.
There are two paths that can take a country to the top of the EPI rankings. First, a country could be gifted with a rich endowment of clean water, diverse biology and not have sullied it with rampant industrialism. That's how Cuba, Colombia and Costa Rica placed so high.
Alternatively, a country could have industrialized and polluted its environment, but eventually gotten rich enough to start cleaning it up. That's the case with the European countries that make up more than half of the top 30.
"The richer you become, the more polluted you become, to a point. Then you become cleaner," says Christine Kim of Yale, research director for the EPI.
The U.S. is still on the upswing, says Esty. "Forty years ago the U.S would have had bad scores" like China (rank: 121st) and India (123rd). America, as it's matured, has made big strides in cleaning up lakes, rivers and streams, with clean drinking water available to practically the entire population. Air quality has gotten much better in places like Los Angeles. What's more, "no country is a better forest steward," says Esty. And despite the plague of pine bark beetles laying waste to millions of acres of forests across the west, "the U.S. is re-foresting at a rapid rate."
Sounds good, so why does the U.S. rank so much lower than those Europeans? "People in the U.S. are shocked the U.S. ranks so low. In Europe they're shocked the U.S. ranks so high," says Esty.
Trace the cognitive dissonance to greenhouse gas emissions, where the U.S. places very poorly because of our reliance on coal for 50% of power generation and our reliance on cars to traverse wide-open spaces. America's fully industrialized peers Japan (ranked 20th), Germany (17th) and the U.K. (14th) did far better. The best way for America to improve its score: make a big push toward generating power from nuclear and natural gas.
But could we ever place better than Cuba, which is ranked ninth? Well, Cuba's scant industrial base limits pollution, while socialized health care helps limit environmental-related illness. At least that's what the data claims.
"There's some made-up data out of Cuba," says Esty. They have problems with the veracity of China's data, too. The U.S. on the other hand has very high data quality because "we [in the U.S.] are able to get bad news published." Despite misgivings on Cuban data, "we don't use our judgment on data to push down countries' rankings."
Another unusual case is Belgium, which lags far behind its neighbors France, the Netherlands and Germany and the rest of Western Europe. Belgium is in 88th place, on par with Ukraine and lower than any other European country. The data on Belgium shows "incontrovertible systematic underperformance," says Esty. Less nuclear power, worse water quality and less protection of open spaces.
Esty cautions that it's more useful for policymakers to compare a country's results with those in its peer group. Desert countries will have trouble scoring high in the rankings because of their complete lack of emissions-free hydropower, and limited ecological diversity. Yet in the 2010 study, for the first time, the researchers decided to count sea water desalination as a renewable water source. This helps the oil-rich countries, which can afford to build desalination plants. (See "Making Sweet Water From (Almost) Perpetual Motion.")
In an enviro-measurement quandry, those oil and gas-rich regimes like Saudi Arabia (99th place) and Qatar (122th), don't get docked for the environmental impact of their exported hydrocarbons.
Esty says that of the 75 nations to give feedback to his researchers on their EPI rankings, none has been more outraged than South Korea. Landing in 94th place, between Gabon and Nicaragua, South Koreans see this study as an insult unbefitting their status as a first-world developed nation. The South Korean ambassador filed a protest. A bureaucrat even called up research director Christine Kim's grandmother back home in South Korea to complain. The South Koreans' overly rosy environmental self-assessment might have something to do with the worse performance of neighboring China and North Korea (147th place). Esty says the data on low levels of biodiversity and significant air pollution aren't in doubt.
A bastion of hope and irony: the most biodiverse place on the Korean Peninsula is the demilitarized zone, says Esty. Yet some of the deer there, because of landmines, only have three legs.
Slideshow: The World's 10 Cleanest Countries
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