In the absence of measured climate and ecological data records, paleoecology, and paleoclimatology provide unique opportunities to examine ecological and climatic conditions across long timescales and provide much needed long‐term context. Across the Arctic there are numerous ecological problems affecting the biota and landscapes of this environmentally sensitive region. Climate change is chief amongst these. This chapter examines the changing ecology of the Arctic from a paleoenvironmental perspective. Using examples from studies throughout the circumpolar Arctic, the changing ecology of the Arctic is examined across longer timescales than typically considered in ecological studies. While instrumental records of climatic change in the Arctic are generally short, dendrochronology can provide key insights into climate variability during the past several centuries to millennia. There are many types of natural archives of ecological and environmental change from marine terrestrial environments in the Arctic.