
Global climatic changes have led to alteration in earth’s capacity to sustain life. Melting of ice, rise in sea-level and increased ocean acidity have affected the entire aquatic ecosystem. Changes in water quality, as a consequence of storms, snow-melt, and periods of elevated air temperature exceeds the thresholds of tolerance, leading to altered distribution and phenology of species and productivity of aquatic ecosystems. Increased atmospheric carbon dioxide concentrations alter ocean chemistry which affects the ecosystem structure and functioning. This review focuses on the adverse effects of climate changes on species habitat and their extinction, deep sea biodiversity and the potential impacts of oxygen-deficient dead-zone expansion, alterations in river flow regimes and hydrological cycle, thereby acting as the biggest challenge. It further emphasizes the need for ability to moderate, cope up with and take advantage of the consequences of climate change while preventing the degradation of ecosystems and preserving our biodiversity.