Oceans cover roughly 71% of Earth’s surface and contain the vast majority of the planet’s water, making them central to climate regulation, biodiversity and human livelihoods
Extent and volume
Oceans cover about 71% of Earth’s surface and hold roughly 97% of the planet’s water, forming the dominant reservoir of Earth’s hydrosphere and shaping global habitability.
Unexplored areas
Despite this immense coverage, much of the ocean remains poorly explored and mapped. Large portions of the seafloor and deep‑sea regions have been surveyed only at low resolution or not at all, leaving many ecosystems and geological features still to be discovered and studied.
Role in climate and circulation
Oceans absorb and redistribute heat and carbon, driving weather patterns and long‑term climate dynamics. They have taken up most of the excess heat from greenhouse gas emissions and a significant share of anthropogenic CO2, which affects ocean temperature, chemistry and sea level.
Biodiversity and human use
The seas host a vast range of life from coastal habitats to the deep sea, supporting fisheries, transport, tourism and cultural practices for billions of people. Healthy ocean ecosystems are also critical for food security, livelihoods and economic activity worldwide.
Exploration and advancing technology
Technological advances—satellite missions, autonomous underwater vehicles, improved mapping sensors and expanded observation networks—are enabling deeper, more comprehensive studies of ocean surfaces and seafloor features, unlocking new data about circulation, biology and change over time.
Why it matters
The oceans’ scale and connectivity mean that local changes can have global consequences. Better mapping, monitoring and stewardship are essential to manage resources, protect biodiversity and understand climate feedbacks that affect human societies everywhere.
Takeaway
Covering over 70% of Earth, the oceans are a single, dynamic system that stores most of the planet’s water, regulates climate, supports immense biodiversity and remains one of the last frontiers for scientific discovery and responsible management.