Unprecedented Macroclimatic Conditions Threaten Tree Species Globally

Research from Aarhus University has warned that anthropogenic climate change poses a significant threat to tree species worldwide, with 69% of species predicted to experience macroclimatic shifts in at least 10% of their range by 2100. This increase in exposure to unprecedented macroclimatic conditions may trigger biome shifts and ecosystem disruptions, particularly in regions such as Eurasia, the northwestern United States and Canada, northern Chile, and the Amazon Delta.

Key Takeaways:

• The study quantified climate change exposure-shifts to species' currently unoccupied climate zones for 32,089 tree species globally by 2100, assessing both species-level and local tree diversity risks.
• On average, 69% of species are predicted to experience macroclimatic shifts in at least 10% of their range, while 14% face exposure in over 50% of their range under a high-emission (4 degrees C warming) future scenario.
• Identifying tree species and areas of high macroclimatic shift exposure allows for targeted conservation strategies, including species stability monitoring, assisted migration, and the protection of climate refugia.
• The research concluded that tree diversity exposure is predicted to be severe in vast regions, including the Amazon Delta, northern Chile, and the northwestern United States and Canada.
• The study's findings provide conservative estimates of climate-driven biodiversity risk, as it focuses solely on macroclimate and does not account for additional stressors such as land-use change or species interactions.

Statistics:

• 69% of tree species are predicted to experience macroclimatic shifts in at least 10% of their range by 2100.
• 14% of tree species face exposure in over 50% of their range under a high-emission (4 degrees C warming) future scenario.
• 32,089 tree species were analyzed in the study to assess climate change exposure-shifts globally.
• The study focused solely on macroclimate and did not account for additional stressors such as land-use change or species interactions.

Sources:

• Proceedings of the National Academy of Sciences. (2025). High Tree Diversity Exposed To Unprecedented Macroclimatic Conditions Even Under Minimal Anthropogenic Climate Change. 122(26).
• Aarhus University. (2025). Research published in Proceedings of the National Academy of Sciences shows significant threat to tree species globally due to anthropogenic climate change.
• National Academy of Sciences. (www.nasonline.org/).
• Proceedings of the National Academy of Sciences. (www.nasonline.org/publications/pnas/).