The plants of the circumpolar Arctic occupy a dynamic system that has been shaped by glacial cycles and climate change on evolutionary timescales. Yet rapid climatic change can compromise the floristic diversity of the tundra, and the ecological and evolutionary changes in the Arctic from anthropogenic forces remain understudied. In this review, we synthesize knowledge of Arctic floral biodiversity across the entirety of the region within the context of its climatic history. We present critical gaps and challenges in modeling and documenting the consequences of anthropogenic changes for Arctic flora, informed by data from the Late Quaternary (~20 ka). We found that previous forecasts of Arctic plant responses to climate change indicate widespread reductions in habitable area with increasing shrub growth and abundance as a function of annual temperature increase. Such shifts in the distribution and composition of extant Arctic flora will likely increase with global climate through changes to the carbon cycle, necessitating a unified global effort in conserving these plants. More data and research on the continuity of tundra communities are needed to firmly assess the risk climate change poses to the Arctic.