Global environmental science, in its current configuration as predominantly interdisciplinary earth systems analysis, owes its existence to technological development in three respects. (1) Environmental impacts of globalization of corporate and military industrial development linked to widespread use of new technologies prompted investigation of ways to understand and anticipate the global nature of such impacts. (2) Extension of the reach of technology itself demands extension of attempts to anticipate and control the environment in which the technology is to function. Thus as (...) the reach becomes global, the environment in question is also global. (3) Such global studies cannot get far without the development of command, control and information technologies (computers, satellites, automated remote sensing devices) which are crucial for data gathering, storage, and analysis and for the simulation modeling, crucial to theory testing and prediction. This network of dependence on technological development gives the global environmental sciences a rather distinctive epistemological profile, one in which some distinctions that we had thought were clear, on the basis of models of classic laboratory sciences (such as those between experiment and deduction or representation and instrument), turn out to be far from clear. In consequence there needs to be a careful evaluation of the extent to which, or the ways in which, these sciences can provide bases for policy decisions. (shrink)