This globally synchronized evolution experiment provides the first direct proof that populations rapidly adapt to distinct climates from standing variation—and that evolutionary predictability forecasts extinction, converting genomic offset from theory into empirical reality.
A five-year globally synchronized evolution experiment across 30 outdoor sites demonstrates that Arabidopsis thaliana populations undergo rapid, repeatable climate adaptation through polygenic selection on standing genetic variation, with evolutionary trajectories following local adaptation patterns that are predictable using genomic offset models, and where high evolutionary predictability in warm climates correlates with population survival while erratic trends signal impending extinction.
Climate change is threatening species with extinction, and rapid evolutionary adaptation may be their only option for population rescue over short ecological timescales. However, direct observations of rapid genetic adaptation and population dynamics across climates are rare across species. To fill this gap, we conducted a replicated, globally synchronized evolution experiment with the plant Arabidopsis thaliana for 5 years in over 30 outdoor experimental gardens with distinct climates across Europe, the Levant, and North America. We performed whole-genome sequencing on ∼70,000 surviving reproductive individuals and directly observed rapid and repeatable adaptation across climates. Allele frequency changes over time were parallel in experimental evolution replicates within the same climates, while they diverged across contrasting climates—with some allele frequency shifts best explained by strong selection between −46% to +60%. Screening the genome for signals of rapid climate adaptation identified a polygenic architecture with both known and novel adaptive genetic variants connected to important ecological phenotypes including environmental stress responses, CAM5 and HEAT SHOCK FACTORs, and germination and spring flowering timing, CYTOCHROME P450s and TSF. We found evolutionary adaptation trends were often predictable, but variable across environments. In warm climates, high evolutionary predictability was associated with population survival up to 5 years, while erratic trends were an early warning for population extinction. Together, these results show rapid climate adaptation may be possible, but understanding its limits across species will be key for biodiversity forecasting.