Oceans and Seas of the World

Introduction

The oceans of the world are among the most awe-inspiring and consequential features of our planet. Covering approximately 71 percent of Earth's surface and containing about 97 percent of all the water on the globe, the world's oceans represent a vast, interconnected system that regulates climate, sustains life, enables commerce, and has shaped the course of human civilization from the earliest times to the present day. Without the oceans, life as we know it on Earth would be impossible. They produce more than half of the oxygen we breathe, absorb enormous quantities of carbon dioxide, moderate temperatures across the globe, and provide food for billions of people.

Earth is home to five named oceans: the Pacific, the Atlantic, the Indian, the Arctic, and the Southern. Together these vast bodies of water form what oceanographers sometimes call the World Ocean, a single connected system of saltwater that encircles every continent. In addition to the five oceans, the world contains dozens of seas, gulfs, bays, and straits, each with its own character, ecology, history, and importance. The Mediterranean Sea, the Caribbean Sea, the South China Sea, the Red Sea, the Arabian Sea, and the Bering Sea are among the most historically and economically significant of these.

This article explores the full breadth of Earth's oceans and seas, from their geological origins and the history of human exploration to their marine ecosystems, their role in shaping global weather and climate, their enormous economic value, and the dramatic historical events that have unfolded upon their waters.

Early History of Discovery and Exploration

Long before written records exist to document the fact, human beings were using the seas to travel, trade, and explore. The story of ocean exploration is one of the great narratives of human history, spanning tens of thousands of years and encompassing cultures on every continent.

Among the earliest and most accomplished seafarers in history were the Polynesian peoples of the Pacific. Beginning around 3,000 years ago, Polynesian navigators set out from the islands of Southeast Asia and over the course of centuries colonized virtually every habitable island in the Pacific Ocean, from Hawaii in the north to New Zealand in the south and Easter Island in the east. They accomplished these extraordinary voyages in double-hulled canoes without compasses or charts, relying instead on their mastery of celestial navigation, wave patterns, ocean swells, bird behavior, and wind currents. The Polynesian achievement remains one of the most remarkable feats of seamanship in all of human history.