Global warming has a significant impact on ocean ecosystems, which are a vital component for life on Earth. Increasing ocean temperatures affect underwater life in various ways. First of all, warming sea water disrupts the distribution of biological wealth. Fish species, for example, often move towards cooler areas, such as north or deeper, to find favorable temperatures. This not only affects spawning patterns and recovery of fish populations, but can also change the structure of marine communities as a whole. Additionally, global warming contributes to ocean acidification. When carbon dioxide (CO2) accumulates in the atmosphere due to human activities, most of the CO2 is absorbed by the ocean, resulting in a decrease in sea water pH. This acidification is detrimental to many organisms, especially species that have calcium carbonate shells or skeletons, such as corals, mollusks and crustaceans. The decline in coral reef health has a direct impact on biodiversity. Coral reefs provide shelter and resources for thousands of species of fish and other marine organisms. Another effect is the increasing frequency and intensity of extreme weather phenomena, such as tropical storms or marine heat waves. This natural disaster can destroy very important marine habitats and coastal ecosystems, such as mangroves and seagrass. As a result, species that depend on these ecosystems for survival are increasingly threatened. Pollution also increases with global warming. Salinity and pollutants from land can worsen already stressed ocean conditions. Worsening water quality has a negative impact on marine life and ecosystem health. Toxic pollution can cause the phenomenon of eutrophication, where excess nutrients make algae grow abundantly, disrupting photosynthesis and reducing oxygen levels in the water. This resulted in the mass death of marine organisms. On the other hand, invasive species thrive in warmer environments. They compete with native species for food and space, which can have fatal consequences for the diversity of local biota. Natural habitats are becoming increasingly depleted, putting native species at risk of extinction. In the long term, the impact of global warming on ocean ecosystems could affect ocean-dependent resources, including fisheries that provide the livelihoods of millions of people around the world. This marine ecosystem stress can also lead to broader ecological imbalances, changing the way ecosystems function and interact. With all these challenges, humans’ role in mitigating the impacts of global warming must be increased to maintain the continuity of ocean ecosystems.