In a new 2006 pilot study, the United States ranked 28th in overall environmental success. There were 133 nations included in the study.

The study is called the Environmental Sustainability Index (ESI) and is headed by Daniel C. Esty, current director of the Yale Center for Environmental Law and Policy. Yale and Columbia universities did the study jointly.

According to the study, only six nations — five Northern European countries and New Zealand — reached 85 percent success or better in meeting a set of critical environmental goals.

Those goals, which were set at September 2000’s United Nations Millennium Summit, ranged from cleaner drinking water to lower ozone levels and greenhouse gas emissions.

Countries in Africa, Central and Southern Asia were among the lowest of the 133 documented countries. India and Pakistan were both among the bottom 20, scoring 47.7 and 41.1 percent, respectively.

The new study differs somewhat from the Environmental Performance Index (EPI), in that the ESI will be more useful in projecting future national and international policies, whereas the EPI is better suited for past evaluation, Esty said in a New York Times interview.

For example, last year the EPI ranked Great Britain 65th in overall environmental performance, but the ESI ranked Britain fifth.

One of the reasons for such a large difference, Esty said, was that 500 years ago almost all of Britain’s trees were cut down. This is something modern governments had no control over, yet are still held accountable for in the EPI. The ESI takes into account Britain’s progress.

The findings in their entirety were issued at the recent World Economic Forum, an annual meeting of political and business leaders. This year, the Forum took place in Davos, Switzerland.

The authors of the study said that the data is skewed and inaccurate at times. For instance, in the area of agricultural, forest and fisheries management, the authors purposefully weighted the study against countries with high levels of subsidies. “In agriculture fisheries and energy sectors have been shown to have negative impacts on resource use and management practices,” the authors said in the introduction to the study.

Also, the study fails to include more than 65 other nations, resulting in serious “data gaps.” Furthermore, there is no widely accepted way of measuring things like land degradation or loss of wetland areas.

Overall, Esty and the other authors of the study hope to provide “a powerful tool for evaluating environmental investments and improving policy returns.”