Global warming has serious impacts on marine ecosystems that have long been noted by scientists and researchers. One of the most striking impacts is an increase in sea water temperature. Higher temperatures can disrupt the natural habitats of many marine species. Coral reefs, for example, are very sensitive to changes in temperature. Rising temperatures cause coral reef bleaching, resulting in loss of biodiversity and threatening marine life that depends on coral reefs as habitat. In addition, global warming causes an increase in ocean acidity levels due to the absorption of carbon dioxide (CO2) by sea water. This process results in a reduction in calcium carbonate which is important for marine organisms such as molluscs, crustaceans and coral reefs. When the availability of calcium carbonate decreases, the ability of these organisms to build strong shells and structures is reduced, threatening their populations. Changes in ocean current patterns are also a significant impact of global warming. These changes can affect the distribution of nutrients in the ocean, which has a direct effect on the maritime food chain. Increased flows or changes in fish migration patterns can negatively impact fishing, which is a lifeline for many coastal communities. Another impact that is no less important is the melting of polar ice. This melting not only causes sea levels to rise, but also removes vital habitat for species such as penguins, polar bears and seals that depend on ice as a habitat for hunting and breeding. Apart from the physical aspect, global warming also disrupts the behavior and life cycles of marine species. Fish and marine mammals may have to adapt at a rapid rate to changes in temperature and habitat, which could result in the rise of invasive species in new areas, affecting the balance of the ecosystem. A food web crisis could also arise as a result of a decline in planktton populations due to increasing ocean temperatures and acidity, because planktton are the basis of the marine food chain. A decrease in planktton could result in reduced food availability for small fish, which in turn would affect larger predators. Biodiversity is one of the things most affected. Many species that cannot adapt quickly to environmental changes will face extinction. This reduces genetic diversity, which is important for the resilience of marine ecosystems. Efforts to understand and address the impacts of global warming on marine ecosystems are becoming increasingly urgent. Deeper research is needed to create effective adaptation strategies and comprehensive protection policies. Through international collaboration and the development of green technology, we can work to reduce negative impacts and protect marine ecosystems that are so valuable to our planet.