The MacroEcological Theory on the Arrangement of Life (or METAL theory) states that biodiversity is strongly, and in a deterministic way, influenced by climate and the environment. This influence mainly occurs through the interactions between the species’ ecological niche and both climatic and environmental changes. Using the ecological niche allows the consideration of underlying processes (genetic and physiological) that are difficult to identify and parametrise for a large number of species. Interaction between the niche and climatic and environmental changes propagate from the species to the community and ecosystem levels and are detectable from the smallest ecosystems to the whole ecosphere. This theory offers a way to make testable ecological and biogeographical predictions to understand how life is organised and how it responds to global environmental changes, including climate change. At the organismal level, the theory predicts species phenology and biogeography, phenologic and biogeographic shifts as well as local and large-scale responses in species’ abundance to climate change and at the community level, it explains the large-scale organisation of life (biodiversity patterns) and community shifts, including abrupt shifts. All these phenomena, which have been separately investigated in the context of climate change, can therefore be connected through the METAL theory.