Introduction
Population growth is one of the most fundamental pressures on sustainability. In IB Environmental Systems and Societies (ESS), the 2026 first assessment syllabus treats population dynamics as a driver of many environmental problems, including food insecurity, water scarcity, biodiversity loss, and climate change.
This topic is popular in exams because it requires systems thinking—students must link human population growth to environmental, social, and economic impacts. By mastering these connections, you’ll be able to write high-mark essays and interpret data effectively in both Paper 1 and Paper 2.
Quick Start Checklist for ESS Students
When revising population growth and sustainability, make sure you can:
- Explain how population growth increases resource demand.
- Connect population growth to ecological footprints and carrying capacity.
- Use population models (e.g., exponential growth, logistic growth).
- Apply case studies showing population pressures.
- Evaluate strategies for sustainable population management.
Population Growth in the ESS Syllabus
Population dynamics link to several ESS themes:
- Resource use: higher demand for food, water, energy.
- Carrying capacity: how many people the Earth (or a region) can sustain.
- Ecological footprints: per capita impacts multiplied by population size.
- Sustainability: balancing development with environmental limits.
Impacts of Population Growth on Sustainability
1. Food Security
- More people require more food.
- Leads to intensified agriculture, deforestation, and soil degradation.
2. Water Resources
- Increased demand for irrigation and urban water supply.
- Contributes to the global water crisis.
3. Energy Use
- Growing populations increase reliance on fossil fuels.
- Slows the transition to renewable energy.
4. Biodiversity Loss
- Expanding agriculture and urban areas reduce habitats.
- Species extinction accelerates with human encroachment.
5. Climate Change
- Population growth amplifies greenhouse gas emissions through energy, transport, and land use.
Population Models in ESS
Students should be familiar with:
- Exponential growth model: population grows rapidly without limits.
- Logistic growth model: growth slows as carrying capacity is reached.
These models help explain how population interacts with sustainability.
Case Studies for Population and Sustainability
- China’s One-Child Policy: population control efforts, mixed success and challenges.
- India: rapid growth straining water and food resources.
- Japan: aging population—different sustainability challenges.
- Sahel (Africa): population growth combined with fragile soils leading to desertification.
Strategies to Manage Population Growth
- Education and empowerment of women.
- Family planning and access to contraception.
- Economic development and reduced poverty.
- Urban planning to reduce ecological footprints.
- International cooperation on sustainable development goals (SDGs).
Population Growth in ESS Exams
Paper 1
Expect graphs of population trends, age structure diagrams, or resource demand curves.
Paper 2
Essay-style questions could include:
- “Discuss the impact of population growth on sustainability.”
- “Evaluate strategies to manage population growth.”
Exam Tips
- Always link population growth to resources. Show the pressure it creates.
- Use case studies. China and India are especially useful contrasts.
- Include models. Draw exponential and logistic curves where relevant.
FAQs
1. Do I need to memorize population numbers?
No exact figures, but approximate trends (e.g., global population ~8 billion and rising) strengthen answers.
2. Is population growth always unsustainable?
Not necessarily. Low ecological footprints or sustainable management can reduce impacts. But growth generally increases pressure on resources.
3. Could population appear in Paper 1?
Yes. Demographic data and graphs are common in Paper 1.
Conclusion
Population growth is a driver of many sustainability challenges in ESS. By linking growth to resource use, carrying capacity, and ecological footprints—and supporting your answers with case studies—you’ll be ready for exam questions on this topic in the 2026 first assessment.
RevisionDojo Call to Action:
Want population comparison charts and exam-ready models? RevisionDojo’s ESS resources simplify complex topics into clear, structured revision tools.
