The impacts of global climate change permeate the majority of contemporary studies of animal and plant ecology and environmental physiology, where particular concerns about effects on biodiversity and biogeography are common. Yet severe conceptual gaps exist across these scales of inquiry when the physiological tolerance of a species becomes defined by mean trait values across its entire range, populations are treated as homogeneous entities, and environmental heterogeneity is collapsed into latitudinal gradients and annual means. These heuristics are common despite abundant evidence that intra- and inter-specific variation in physiological tolerance is pervasive, that heterogeneity in environmental stressors can vary as much over the scale of a meter as it can thousands of km, and that often less than half of range boundaries are moving in the expected poleward direction. We explore the cognitive dissonance that exists across physiological to biogeographic scales of scientific approach, and argue that it can be explained by several well-known principles of cognitive science: the tendency of humans to simplify complexity into simple cognitive construals; the “fallacy of misplaced concreteness” when these simplified heuristics are conflated with reality; and the social framework of modern science that further rewards and reifies these simplifications. Using work from our own groups and others, we explore how cross-scalar approaches that span molecular biology, physiology and ecology and which consider true variation in nature can provide a means of challenging these unconscious biases and provide a pathway forward to better understand the likely impacts of ongoing environmental change.