<p>Climate change and environmental disturbances have serious and long-term impacts on the dynamics of planktonic ecosystems, however, the mechanisms by which their combined effects affect the growth of phytoplankton are still unclear. This paper examines the dynamics of a phytoplankton-zooplankton model incorporating climate change and stochastic environmental fluctuations. Climate change is characterized by the synergistic effects of wind, light, and pH, while stochastic environmental disturbances are modeled using the mean-reverting Ornstein-Uhlenbeck process. Notably, the model accounts for the fear effect on phytoplankton growth, a factor rarely considered in existing studies. For the deterministic model, key analyses include the boundedness of solutions, the stability of potential equilibria, the existence of Hopf bifurcation and sensitivity analysis to assess the impact of critical parameters on plankton dynamics. For the corresponding stochastic model, the focus is on the existence of a globally unique positive solution, the presence of ergodic stationary distribution, and plankton survival dynamics, including persistence in the mean and stochastic extinction. These theoretical investigations provide a foundation for subsequent numerical simulations. The numerical analysis reveals that both climate change and environmental noise play pivotal roles in shaping phytoplankton growth dynamics. In deterministic scenarios, reduced pH undermines plankton persistence but stabilizes phytoplankton-zooplankton interactions. In randomly disturbed environments, the study clarifies how climate change influences the mechanisms driving the emergence or decline of phytoplankton blooms. Overall, this research offers new insights into potential strategies for controlling or preventing phytoplankton blooms.</p>