IB ESS — Topic 4.1

Water systems

Topic 4.1 introduces the global hydrological cycle, freshwater systems, and ocean circulation patterns. Students study water storage, transfers between reservoirs, and how human activities affect the natural water cycle — foundational knowledge for the water unit in IB ESS.

Sub-topics in Topic 4.1

4.1.1The hydrological cycle 4.1.2Water stores and flows 4.1.3Drainage basins 4.1.4Water and climate regulation

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