Permafrost: A single activity over a limited period of time may not cause significant impacts to the permafrost. However, multiple activities over an extended period could have serious, even irreversible effects.
Airborne contaminants: Because of atmospheric circulation in the Northern hemisphere, the Arctic is a sink for airborne contaminants. This is an important consideration when determining the geographic boundaries of the analysis. Activities that are a considerable distance from the proposed activity may need to be evaluated if effects from air emissions are an issue.
Subsistence harvest: Many activities in the Arctic have the potential to affect subsistence harvest activities of indigenous people. The subsistence lifestyle of indigenous people is indirectly affected by activities that affect the marine mammals, birds, or fish that constitute subsistence resources. Because many of these resources are migratory, the cumulative analysis must consider effects that occur along the migration route. Some activities may directly affect the subsistence harvest by interfering with subsistence hunting activities.
Social and cultural effects: Because of their distinctive culture and unique lifestyles, native communities are particularly susceptible to activities of western and other non-indigenous societies. A single, transitory activity may not have significant or long-lasting societal effects. However, multiple activities occurring over an extended period are more likely to have substantial and possibly irreversible effects on these communities.