Climate tipping events, where climatic subsystems shift to alternative equilibria as a consequence of climate forcing, may have abrupt and drastic impacts on global climatic patterns. Such large-scale and irreversible qualitative changes to the state of global circulation may greatly affect ecosystems. In particular, for biodiversity, climate tipping events may produce novel climate conditions that expose species to potentially stressful climatic conditions outside their realized historical limits. To quantify the patterns of these limits for species across different aspects of climate, we introduce the ClimLimits database, a high-resolution record of terrestrial and freshwater species’ realized climatic niche limits in 44 limits. Using this, we then quantify the exposure fractions over their range of 43,320 species worldwide to 16 of these limits in the face of future climate tipping points.

We model future climates with novel projections forcing the emergence of two climate tipping events, namely the weakening of the Atlantic Meridional Overturning Circulation (AMOC) and the dieback of the Amazon Rainforest (ARF), as well as a third control scenario of stabilizing warming without tipping. Our analysis reveals frequency, intensity and duration of heatwaves as primary drivers of exposure across species in all three scenarios.

However, there are critical differences in exposure patterns across other variables - AMOC weakening changes climate variability and extreme event patterns, while the ARF dieback amplifies exposure to extreme rainfall and drought. Additionally, by looking at spatial exposure patterns across ecosystems, we identify the additional impact of AMOC weakening as increasing exposure in the tropics in South America and Africa, while reducing exposure in Europe and North America. The primary effect of ARF dieback is localized largely to South America, but also has appreciable cascading impacts in other tropical ecosystems. Our results suggest that we may underestimate future climate change impacts on biodiversity loss if we do not account for the possibility of long-lasting and irreversible climate tipping point events.