Abstract

Phenotypic plasticity is often considered a key mechanism enabling organisms to tolerate global change stress, yet its adaptive role remains debated. We suggest that this uncertainty stems from inconsistency in how global change is defined, insufficient consideration of context dependency, and analyses conducted at species or metapopulation scale. To address these issues, we propose a framework that emphasizes partitioning global change into distinct dimensions---mean change, variability, stochasticity, and episodic events---all of which present unique challenges for organisms. We also highlight the importance of considering the tradeoffs between cost, speed, and flexibility of trait plasticity to predict when different types of traits may facilitate adaptation. Recognizing that global change impacts vary across geographic ranges, we advocate for population-level approaches that incorporate historical environmental conditions, multivariate trait responses, and region-specific stressors. Our synthesis provides methodological guidance for designing experiments and leveraging natural gradients to better understand the interplay between global change dimensions and functional traits. While we focus on animals due to their diverse trait repertoires, the concepts presented here are broadly applicable across taxa. By refining definitions and linking trait plasticity to distinct global change dimensions, this framework offers a pathway to more predictive, actionable insights into species resilience under rapidly changing environmental conditions.