BACKGROUND:Climate change impacts have now been documented across every ecosystem on Earth, despite an average warming of only ~1°C so far. Here, we describe the full range and scale of climate change effects on global biodiversity that have been observed in natural systems. To do this, we identify a set of core ecological processes (32 in terrestrial and 31 each in marine and freshwater ecosystems) that underpin ecosystem functioning and support services to people. Of the 94 processesconsidered, 82% show evidence of impact from climate change in the peer-reviewed literature. Examples of observed impacts from metaanalyses and case studies go beyond wellestablishedshiftsin speciesrangesandchanges to phenology and population dynamics to include disruptions that scale from the gene to the ecosystem.