Global climate change has a significant impact on marine ecosystems in various parts of the world. Rising sea temperatures, decreasing pH, and increasingly severe pollution are some of the main issues affecting biodiversity and the balance of marine ecosystems. One of the most striking impacts is warming ocean temperatures. This increase in temperature causes the expulsion of fish species and other marine organisms that are unable to adapt. For example, tuna and other types of fish tend to move to cooler waters. These shifts are changing the structure of marine communities and adversely impacting fishing industries that depend on certain species. Apart from temperature, the absorption of carbon dioxide from the atmosphere also causes a decrease in the pH of seawater, which is known as ocean acidification. This process threatens the life of organisms that have shells, such as shellfish and coral reefs, because their ability to build and maintain calcium carbonate structures is hampered. The decline in the quality of coral reefs not only affects biodiversity, but also impacts the ecosystems that depend on them for protection and feeding grounds. In addition, the phenomenon of coral bleaching, which occurs due to heat stress, is becoming increasingly common. Bleaching indicates that colonies of zooxanthellae, symbiotic algae that provide color and nutrition to corals, have been expelled. If this condition is prolonged, coral reefs can die, resulting in loss of habitat for thousands of fish and invertebrate species. Plastic pollution is also a serious problem for marine ecosystems. With so much plastic waste entering the ocean, marine animals often become trapped or consider the waste as food, resulting in death or malnutrition. This pollution can also change the food chain and affect species at various levels. The impacts of climate change are also visible in the increase in the frequency and intensity of tropical storms. Stronger storms can cause physical damage to marine habitats, including coral reefs and mangroves, which serve as coastal protection and gathering places for various marine organisms. Changes in ocean current circulation patterns can affect nutrient distribution, which is important for primary productivity. This can lead to a decrease in ecosystem productivity, reducing the necessary food supply for marine species. A decline in fish populations will impact local economies that depend on marine products. Sustainable management and mitigation efforts are needed to face this challenge. We need to promote environmentally friendly fishing practices and raise awareness about the importance of keeping the sea clean from waste. These steps will not only help protect marine ecosystems, but also ensure the sustainability of marine resources for future generations. Global conservation initiatives are also vital, with many organizations working to improve the state of coral reefs and other marine habitats. Through research and international collaboration, we can drive more effective action to reduce the impacts of climate change on oceans around the world.