Global warming has a significant impact on marine ecosystems, which include oceans, coral reefs, and various species that depend on these ecosystems. One of the main consequences of global warming is an increase in sea water temperatures. This increase causes thermal stress in marine organisms, especially coral reefs, which are very sensitive to temperature changes. This stress can lead to coral bleaching, a phenomenon in which corals lose the symbiotic algae that provide them with color and nutrients. As a result, corals become more susceptible to disease and death. Apart from increasing temperatures, global warming also causes ocean acidification. When the atmosphere absorbs more carbon dioxide (CO2), much of this CO2 dissolves into seawater, reducing the water’s pH. Ocean acidification can disrupt the process of shell and skeleton formation in marine organisms such as molluscs and other calcium-producing organisms. This has the potential to threaten the maritime food chain, as species lower in the ecosystem will face difficulties in surviving. Climate change is also causing sea levels to rise, which threatens coastal habitats such as mangroves and seagrass. This habitat is very important for maintaining biodiversity and protecting beaches from erosion. Loss of coastal habitats can result in reduced populations of marine species that depend on these places for shelter and breeding. Species migration is also a serious impact of global warming. Many species of fish and other marine animals are starting to move to colder areas in search of more suitable environments. These movements can change local ecosystems, reducing the number of endemic species and increasing competition between new and local species. The socio-economic impact of these changes is enormous. The fisheries and tourism sectors have been disrupted due to the decline in fish populations and damage to coral reefs. Local fishermen and communities dependent on marine resources will face increasing challenges, which could trigger conflicts over rights to access and use of resources. Awareness of the impact of global warming on marine ecosystems is increasing, with many studies and initiatives aimed at protecting and preserving the marine environment. Ecosystem-based management efforts and climate change mitigation policies are becoming increasingly important to maintain the health of marine ecosystems in the future. Measures such as establishing marine protected areas, reducing greenhouse gas emissions, and regulating sustainable fishing must be intensified to build the resilience of marine ecosystems to climate change. With appropriate collective action, the sustainability and health of marine ecosystems can be protected for future generations.