The impact of climate change on human ecology in the northern latitudes is dependent upon the rate, magnitude, and duration of expected change. This paper provides a foundation for understanding these important components by describing elements of the high-latitude environment that control climate in four broad climatic zones: Arctic coast, sub-Arctic interior, Pacific coast, and alpine transition. These climate controlling patterns are compared with output from general circulation models that simulate potential change from the effects of increasing atmospheric carbon dioxide concentrations, or its greenhouse gas equivalent. In addition, model output and climate controls are compared with paleo and historical climate analogues that show past regional responses to global climate change.