Coral reefs, vital ecosystems renowned for their biodiversity and economic value, face escalating threats from the intensifying greenhouse effect caused by human activities. This study examines the impacts of rising greenhouse gas concentrations on coral reefs, focusing on coral bleaching and sea level rise. Elevated sea surface temperatures, driven by the greenhouse effect, induce physiological stress in corals, leading to the expulsion of zooxanthellae and subsequent bleaching—impairing photosynthesis and growth. Meanwhile, rising sea levels, resulting from thermal seawater expansion and melting polar ice, risk submerging coral reefs, further degrading their health and ecological functions. These changes threaten marine ecotourism by diminishing the appeal of coral reefs as tourist destinations while undermining biodiversity and coastal protection. The findings highlight the urgent need for sustainable practices and policy interventions to mitigate climate change's effects on coral reef ecosystems and the communities that depend on them.