Introduction
Urbanization is one of the defining global trends of the 21st century. More than half the world’s population now lives in cities, and this number continues to rise. In IB Environmental Systems and Societies (ESS), the 2026 first assessment syllabus places a clear focus on urban systems because they bring together many of the course’s core themes: population growth, ecological footprints, sustainability, and resource management.
So yes—you do need to study urban systems in ESS. Examiners use this topic because it connects human societies and environmental challenges in ways that are easy to illustrate with data and case studies.
Quick Start Checklist for ESS Students
When studying urban systems, make sure you can:
- Define what an urban system is in ESS terms.
- Explain how urbanization impacts resources, pollution, and sustainability.
- Use case studies of cities for comparison.
- Evaluate strategies for sustainable urban living.
- Link urban systems to ecological footprints.
What Are Urban Systems in ESS?
- ESS treats cities as systems with inputs, outputs, storages, and flows.
- Inputs: energy, food, water, raw materials.
- Outputs: waste, pollution, carbon emissions.
- This systems perspective shows why urbanization creates sustainability challenges.
Impacts of Urban Systems on Sustainability
1. Resource Demand
Cities consume huge amounts of food, water, and energy.
