ROBERT COSTANZA,^* HERMAN DALY,^** CARL FOLKE,^*** PAUL HAWKEN,^**** C. S. HOLLING,^***** ANTHONY J. McMICHAEL,^****** DAVID PIMENTEL,^******* DAVID RAPPORT<sup>********


*</sup>Robert Costanza (e-mail: costza@cbl.umces.edu) is a professor in the Center for Environmental Science and Biology Department, and the director of the Institute for Ecological Economics, University of Maryland, Solomons, MD 20688.
^**Herman Daly is a professor in the School of Public Affairs, University of Maryland, College Park, MD 20742-8311.
^***Carl Folke is a professor in the Centre for Research on Natural Resources and the Environment and the Department of Systems Ecology, Stockholm University, S-106 91 Stockholm, Sweden, and at the Beijer Institute, S-106 91 Stockholm, Sweden.
^****Paul Hawken is a professor in the Department of Landscape Architecture and Environmental Science, Utah State, Logan, UT 84322.
^*****C. S. Holling is a professor in the Department of Zoology, University of Florida, Gainesville, FL 32611-8525.
^******Anthony J. McMichael is a professor in the Department of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK.
^*******David Pimentel is a professor in the Department of Entomology, Cornell University, Ithaca, NY 14853.
^********David Rapport is a professor in the Faculty of Landscape Architecture and Rural Planning, University of Guelph, Guelph, Ontario, Canada N1G 2W1, and in the Faculty of Medicine, Department of Toxicology and Pharmacology, The University of Western Ontario, London, Ontario, Canada N6A 5B8.