ABSTRACT
Integrated assessments of global change disturbances involve “end-to end” analyses of relationships and data from physical, biological and social sciences (e.g., see the reviews and references in Weyant et al. [1], Morgan and Dowlatabadi [2], Rotmans and van Asselt [3], Parson [4], Rothman and Robinson [5], Schneider [6]). Often, data or processes are collected or simulated across vastly different scales – for example, consumption at national scales and consumer preferences at family scales, or species competition at field plots the size of a tennis court and species range boundaries at the scale of a half continent, or thunderstorms at ten kilometers and the grid cells of a global climate model at hundreds of kilometers, or the response of an experimental plant in a meter-square chamber to increased concentrations of CO2 but a prediction of ecosystem response to CO2 at biome scales of a thousand kilometers. Not only must individual disciplines concerned with the impacts of global change disturbances – like altered atmospheric composition or land use and land cover changes – often deal with five orders of magnitude difference in spatial scales, but integrated studies must bridge scale gaps across disciplinary boundaries as well. For instance, how can a conservation biologist interested in the impacts of climate change on a mountaintoprestricted species scale down climate change projections from a climate model whose smallest resolved element is a grid square 250 kilometers on a side? Or, how can a climate modeler scale up knowledge of evapotranspiration through the sub-millimeter-sized stomata of forest leaves into the hydrological cycle of the climate model resolved at hundreds of kilometers? The latter problem is known as up-scaling (see e.g., Harvey [7]), and the former one,
downscaling (see e.g., Easterling et al. [8]). This cross-disciplinary aspect can be particularly daunting when different scales are inherent in different sub-disciplines with different traditions and methods – particularly likely in crossing natural and social scientific boundaries. Only a greater understanding of the methods and traditions of each of these sub-disciplines by practitioners in the others will likely help to facilitate that kind of epistemic boundary bridging across very different disciplines operating at very different scales.
