Global warming has a significant impact on marine ecosystems, which include flora and fauna and the overall health of the waters. One of the main impacts is increasing sea temperatures. Rising temperatures can cause bleaching of coral reefs, which are important habitats for many marine species. Bleaching occurs when coral expels the symbiotic algae that provide nutrients and color, resulting in mass deaths if temperatures do not return to normal. In addition, increasing ocean temperatures result in changes in species distribution. Fish and other sea creatures may move to colder waters, disrupting food chains and changing local ecosystems. This means that fishing communities are also affected, as they will face reduced catches or have to adapt to new species. Climate change also has an impact on ocean acidity levels. When CO2 accumulates in the atmosphere, most of it is absorbed by the oceans, causing a drop in pH. More acidic water threatens organisms that have shells, such as clams and mollusks, because it is difficult for them to form the hard structures necessary to survive. If this condition continues, it could have a domino impact on the entire marine ecosystem. In addition, rising sea levels caused by melting polar ice and thermal expansion of sea water have the potential to change coastal habitats. Mangrove, seagrass and mangrove swamp ecosystems that serve as protection and breeding grounds for many species can be submerged. Loss of this habitat will result in a decrease in biodiversity and the ecosystem’s ability to function properly. Global warming also affects weather patterns, which impact seasonal cycles. Phenomena such as El Niño and La Niña are becoming more intense, affecting marine biological productivity. This not only affects marine life but also the communities that depend on these ecosystems for their livelihoods. In response to these changes, conservation initiatives are increasingly in demand. The need for sustainable management, rehabilitation of coral reefs and protection of marine areas is very important to maintain the health of marine ecosystems. Awareness of the impacts of climate change must be increased to encourage collective action to address this problem, from individuals to global policies. Therefore, it is important for the global community to collaborate in mitigation and adaptation efforts to the impacts of global warming on marine ecosystems. These steps will not only protect marine biodiversity, but also support ecosystem resilience and safeguard the well-being of humans who depend on marine resources.