The impact of global climate change on marine ecosystems is very significant and complex. One of the biggest impacts is an increase in sea temperatures. As a result of global warming, water temperatures in the oceans continue to rise, resulting in changes in the distribution of marine species. Fish species in particular, which are often sensitive to temperature, may change their migration patterns, forcing fishermen and the fishing industry to adapt quickly. Furthermore, ocean warming causes the phenomenon of coral bleaching, in which zooxanthellae, the symbiotic algae that provide color and nutrition to the coral, die. This has a direct impact on marine biodiversity and the health of coral reef ecosystems. Coral reefs are important habitats for many marine species, and damage to these structures can reduce populations of fish and other marine organisms. Climate change is also causing increased carbon dioxide levels in the oceans, resulting in seawater acidification. This acidification impacts organisms that build shells, such as mollusks and coral reefs, disrupting their ability to grow and develop. In the long term, this could threaten the entire marine food chain and affect biodiversity. Sea level rise due to melting polar ice creates a threat to coastal ecosystems. Mangrove and salt marsh areas, which are important for filtering pollutants and providing habitat for many species, are threatened by flooding and erosion. This loss of habitat can result in population declines of species that depend on these ecosystems for survival. Additionally, extreme changes in weather patterns, including storms and marine heat waves, can have a devastation effect on marine ecosystems. Stronger and more frequent storms can damage marine and coastal habitats, affecting biodiversity. Marine heat waves can cause mass deaths of marine organisms that cannot adapt quickly to high temperatures. The socio-economic impact of climate change on marine ecosystems is also quite large. Increased instability in fisheries output could destroy the livelihoods of coastal communities and increase conflict between countries. Additionally, declining water quality and depletion of marine resources could affect global food access, increasing the risk of a food crisis. Meanwhile, climate change mitigation efforts can play an important role in protecting marine ecosystems. Building large protected areas and regulating sustainable fishing practices can help restore and protect populations of threatened marine species. Global efforts to reduce greenhouse gas emissions are also very important in controlling the rate of climate change, and directly reducing negative impacts on marine ecosystems. Scientists continue to conduct research to further understand how climate change affects marine ecosystems. This knowledge is necessary for effective adaptation strategies and conservation actions that can help protect the oceans for future generations.