ECONOMIC-IMPACTS OF CLIMATIC-CHANGE ON THE GLOBAL FOREST SECTOR - AN INTEGRATED ECOLOGICAL ECONOMIC ASSESSMENT/

Increased atmospheric concentrations of CO2 and any associated climati c changes will affect many aspects of forests, including net primary p roductivity. Operating through normal timber-supply mechanisms, change s in forest growth will affect forest products markets-production, con sumption, prices and trade-throughout the world. These impacts are sim ulated by linking the climatic change scenarios from the four commonly used general circulation models (GCMs) of climate with a model of glo bal vegetation response (the Terrestrial Ecosystem Model) and a model of global forest products trade (the University of Washington Cintrafo r Global Trade Model). The four GCMs produce surprisingly consistent e conomic results, with expanding net primary productivity of the world' s forests generally hurting timber producing regions and benefiting co nsumers. The overall net economic impact is positive, with the net pre sent value (computed with a 4% real discount rate) of the benefits to the forest sector ranging from $US1980 10.7 billion to 15.9, depending on the choice of GCM and economic scenario. Uncertainty in the econom ic models appears to be at least as great as the uncertainty in the GC Ms.