The arctic tundra and boreal forest were once considered
the last frontiers on earlh because of their vast expanses
remote from agriculturaland-use change and industrial
development. These regions are now, however, experiencing
environmental and social changes that are as rapid
as those occurring anywhere on eadh. This paper summarizes
the role of northern regions in the global system
and provides a blueprint for assessing the factors that govern
their sensitivity to social and environmental chanqe