Climate refugia implications of warming and land-intensive mitigation under overshoot

Biodiversity loss is expected to escalate with every increment of global warming. Simultaneously, land-intensive climate change mitigation strategies, such as afforestation and bioenergy, may further compound biodiversity loss. So far, the magnitude of these two drivers has not been compared in the context of temperature overshoot, meaning the temporary exceedance of a targeted global warming limit. By combining spatial data on climate refugia (areas sheltering biodiversity from climate change), bioenergy cropland, and forestation for multiple cost-effective scenarios with varying levels of climate action and overshoot, we illustrate how both warming and mitigation affect today’s climate refugia across five integrated assessment models. Decisive climate action, compatible with limiting warming to 1.5 °C, reduces the combined loss of today’s climate refugia due to warming and mitigation-related land-use change by more than 50% compared to current climate policies, outweighing potentially negative implications of mitigation at the global level by limiting the magnitude and duration of warming above 1.5 °C. We observe notable differences across regions and the considered model frameworks. Overshoot implications strongly depend on the underlying biodiversity recovery assumptions.