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Lesson 8
Introduction to Earth's Climate

What role do the oceans play in global climate change?

Confederation Bridge across the Northumberland Strait,
viewed from Prince Edward Island, Canada.

We live in a world of water. Over 70% of Earth's surface is covered by oceans, with an average depth of four thousand metres. Approximately 3.1 billion cubic kilometres of water are contained in the oceans. These waters constitute roughly 99% of the living space on earth, supporting over 230,000 identified marine species.

Due to the high heat capacity of liquid water, the uppermost 3 metres of the world ocean hold as much heat energy as the entire atmosphere. In addition, the oceans and the atmosphere are in dynamic equilibrium, constantly exchanging energy, water, and carbon. Human activities are currently shifting this balanced system. As such, it is important to consider the role that oceans have in climate change.