A globally coherent fingerprint of climate change impacts across natural systems

States that causal attribution of recent biological trends to climate change is complicated because non-climatic influences dominate local, short-term biological changes
States that any underlying signal from climate change is likely to be revealed by analyses that seek systematic trends across diverse species and geographic regions; however, debates within the Intergovernmental Panel on Climate Change (IPCC) reveal several definitions of a ‘systematic trend’
Explores these differences, applying diverse analyses to more than 1,700 species, and shows that recent biological trends match climate change predictions
Global meta-analyses documented significant range shifts averaging 6.1 km per decade towards the poles (or metres per decade upward), and significant mean advancement of spring events by 2.3 days per decade
Defines a diagnostic fingerprint of temporal and spatial ‘sign-switching’ responses uniquely predicted by twentieth century climate trends
Finds this diagnostic fingerprint for 279 species among appropriate long-term/large-scale/multi-species data sets
This suite of analyses generates ‘very high confidence’ (as laid down by the IPCC) that climate change is already affecting living systems.