Ocean Ecosystem Is a Big Player for the Global Climate Change

The ocean ecosystem plays a central and irreplaceable role in regulating Earth’s climate, acting as a major reservoir for heat, carbon, and biological activity. Covering more than 70% of the planet’s surface, the oceans absorb the majority of excess heat from global warming and approximately a quarter of anthropogenic carbon dioxide emissions, thereby buffering the pace of climate change. This review article examines the ocean ecosystem as a major driver and moderator of global climate change, integrating physical, chemical, and biological perspectives. It explores ocean circulation, carbon sequestration, marine biodiversity, and biogeochemical feedbacks, while also addressing how climate change is reshaping ocean processes through warming, acidification, deoxygenation, and ecosystem disruption. Rather than treating the ocean as a passive sink, this review argues that the ocean ecosystem is an active and dynamic climate regulator whose resilience is now under threat. Understanding and protecting ocean ecosystems is therefore essential for effective climate mitigation and adaptation strategies.