PARENT SESSION
Special Session 13: Millenium Ecosysyem Assessment Part II: Frontiers in multi-scale assessments of ecosystem services
Organized by: SR Carpenter and W Reid
Thursday, August 11, 1:30 PM - 5:00 PM, Exhibit Hall 210a-e, Level 2, Palais des congrès de Montréal
State of the art in modeling ecosystem services.
Kareiva, Peter*,1, 2, 3, 1 The Nature Conservancy, Washington, DC2 Environmental Studies, Santa Clara University, Santa Clara3 Bren School of Environmental Management, UCSB, Santa Barbara
ABSTRACT- It is hard to measure ecosystem services, and even harder to forecast changes in ecological services according to alternative scenarios of global change. Nonetheless, in order to assess different scenarios and the implications of fundamental policy or societal choices, the Millennium Assessment used a series of interlocking models of biodiversity, land-cover, land-use, fisheries, food, human health, and nutrient cycling services to distill alternative possibilities. Those who see glasses as half empty will complain about how existing models fail to couple interacting processes, are based on biased and idiosyncratic taxonomic groups or geographic regions, never get around to rigorous model assessment via common learning data sets, and do not work well across multiple scales. Those who see glasses as half full will marvel how far this modeling has come from it parochial roots, feel good about the theoretical innovations being pushed because of this modeling ambition, and predict tremendous advances in the next ten years. Regardless of one's views about half-empty or half-full glasses, no one can deny the importance of developing models that better forecast changes in ecosystem services under different future scenarios. 
Key words: ecosystem services, global models, biodiversity, global scenarios