Ecological forecasting and long-term ecological research are synergistic. Long-term data are essential for calibrating models, and forecasts are hypotheses to be tested by long-term research. Existing models are limited in scope. Generally they provide predictions of biological, biogeochemical or physical trajectories of ecosystems, given specified inputs including human actions. Integrated social-ecological dynamics are hard to predict. Predictability is limited for many reasons including nonlinear processes, the propagation of random shocks in an increasingly connected world, poor understanding of social-ecological feedbacks, and the role of human volition.
Despite these difficulties, the need to think about the future of social-ecological systems cannot be avoided. The definition of sustainability includes the notion of non-decreasing wealth: sustainable policies meet the needs of the present without undermining the ability of future generations to meet their needs. Inevitably, environmental actions affect future generations as well as the present. Therefore present-day decision makers must think about long-term consequences of environmental actions.
Scenarios are a structured set of stories about the future designed to explore the logical consequences of key uncertainties. Constructing these stories provides a tool for integrating heterogeneous information (including traditional socio-economic and ecological data, model runs, and perspectives of diverse individuals). Building the scenarios and evaluating their consequences can help the public, decision makers and scientists organize ideas about changes in regional social-ecological systems. Reactions by decision-makers to alternative futures can help build resilience against plausible but unpredictable events. Scenarios also suggest new priorities for modeling and empirical research, and teaching scenario planning should better prepare future scientists and managers for dealing with complex environmental challenges in the 21st century.
NTL-LTER was a pioneer in scenario development as a pilot project for the Scenarios Working Group of the Millennium Ecosystem Assessment (http://MAweb.org). Interactive workshops created four different stories about the future of the Northern Highland Lake District (NHLD).
After the scenario storylines were written, a computer model was built to investigate consequences of the scenarios for demographics, economics, forests, and lakes. The model was used as a computer game for managing the NHLD in a simulated world. Follow-up workshops, meetings with decision-makers, public presentations, a web site, and a survey distributed the scenarios to the public.
NTL-LTER investigators are now developing a new set of scenarios of social-ecological change in the Yahara Watershed around Madison, Wisconsin from 2010 to 2060 (http://wsc.limnology.wisc.edu). The overarching questions for the scenarios exercise are: