Climate change is reshaping global biodiversity as species respond to changing temperatures. We related trends in species richness and abundance from 21,500 terrestrial and marine assemblage time series across temperate regions to changes in air or sea surface temperature. We found a strong coupling between biodiversity and temperature change in the marine realm, where species richness mostly increased with warming. However, biodiversity responses were conditional on the baseline climate, such that in initially warmer locations richness increase was more pronounced, while abundance declined with warming. In contrast, we did not detect systematic temperature-related richness or abundance trends on land, despite a greater magnitude of warming. As the world is committed to further warming, substantial challenges remain in maintaining local biodiversity amongst the non-uniform inflow and outflow of ‘climate migrants’. Temperature-driven community restructuring is especially evident in the ocean, whereas climatic debt may be accumulating on land.

Temperature-related biodiversity change across marine and terrestrial systems