Widespread ecological novelty across the terrestrial biosphere.

Human activities have transformed many wild and semiwild ecosystems into novel states without historical precedent. Without knowing the current distribution of what drives the emergence of such novelty, predicting future ecosystem states and informing conservation and restoration policies remain difficult. Here we construct global maps of three key drivers generating novel conditions-climate change, defaunation and floristic disruption-and summarize them to a measure of total novelty exposure. We show that the terrestrial biosphere is widely exposed to novel conditions, with 58% of the total area exposed to high levels of total novelty. All climatic regions and biomes are exposed to substantial levels of novelty. Relative contributions of individual drivers vary between climatic regions, with climate changes and defaunation the largest contributors globally. Protected areas and key biodiversity areas, whether formally protected or not, have similar exposure, with high total novelty experienced in 58% of cells inside protected areas and 56% inside key biodiversity areas. Our results highlight the importance of investigating ecosystem and biodiversity responses to rising ecological novelty for informing actions towards biosphere stewardship.