Climate change is increasingly characterized by heightened variability, unpredictability, and extreme events, presenting profound challenges for animal populations across global ecosystems. This review synthesizes current scientific literature to examine how climatic uncertainty, beyond changes in mean temperature, reshapes animal population patterns, including abundance, distribution, migration, and long-term persistence. Drawing on evidence from terrestrial, freshwater, and marine systems, we highlight how fluctuations in temperature and precipitation disrupt demographic processes such as survival, reproduction, and recruitment, often increasing extinction risk in species with narrow physiological tolerances or specialized ecological niches. Particular attention is given to migratory species, where climate-driven shifts in phenology across breeding and non-breeding regions generate trophic mismatches and weaken population connectivity. The review further explores how extreme climatic events can restructure age composition and density-dependent dynamics, producing non-linear and sometimes counterintuitive population responses. Importantly, climate uncertainty rarely acts in isolation; it interacts synergistically with habitat fragmentation, land-use change, and emerging disease pressures, compounding stress on wildlife populations. We also assess the growing evidence that climate variability accelerates the erosion of genetic diversity, thereby constraining adaptive capacity and evolutionary resilience. By comparing theoretical models with empirical observations, this review underscores the limitations of population assessments that focus solely on average climatic trends and neglect variability and extremes. We conclude by identifying critical knowledge gaps and outlining future research priorities, including the integration of climate variability into population models, long-term monitoring, and adaptive conservation planning. Understanding animal population patterns under uncertain climates is essential for anticipating biodiversity trajectories and informing resilient management strategies in an era of accelerating environmental change.
Ambreen Ilyas (Fri,) studied this question.