| August, 1999 | Allen Hammond, Emily Matthews |
| November, 1998 | Ben Sinnamon (World Wildlife Fund) and Sandy Buffett (World Resources Institute)
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| October, 1998 | Matthew B. Arnold and Robert M. Day
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| May, 1998 | Janet Ranganathan |
| December, 1997 | David Barkin, Universidad Autonoma Metropolitana, Mexico City
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| December, 1997 | Zou Ji, Renmin University, Beijing
|
| September, 1997 | C. Ford Runge, Eugenio Cap, Paul Faeth, Patricia McGinnis, Demetri Papageorgiou, James Tobey, Robert Houseman
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| September, 1997 | Tamar Gunter
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| July, 1997 | Janet Ranganathan, Daryl Ditz
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| April, 1997 | Allen Hammond, Albert Adriaanse, Stefan Bringezu, Yuichi Moriguchi, Eric Rodenburg, Donald Rogich, Helmut Schütz |