Introduction
For HL students in IB Environmental Systems and Societies (ESS), the 2026 first assessment introduces more emphasis on international environmental law. While SL students focus on scientific and systems concepts, HL students must also understand how legal frameworks shape sustainability.
This topic is exam-relevant because it highlights the global nature of environmental problems—such as climate change, biodiversity loss, and pollution—and shows how international cooperation can (or cannot) solve them.
Quick Start Checklist for HL Students
When revising international law in ESS, make sure you can:
- Explain why environmental issues require international agreements.
- Identify key treaties relevant to ESS topics.
- Evaluate the successes and limitations of these treaties.
- Use case studies in exam answers.
- Link law to sustainability, ethics, and economics.
Why International Law Matters in ESS
Environmental problems often cross borders:
- Air pollution drifts across countries.
- Oceans are shared commons.
- Climate change affects the entire planet.
International law provides frameworks for cooperation, but its effectiveness depends on political will, enforcement, and equity.
Key Treaties and Agreements to Know
1. Montreal Protocol (1987)
- Target: ozone-depleting substances (CFCs).
- Success story: ozone layer is now recovering.
- Strengths: universal ratification, binding targets.
- Weaknesses: slow recovery due to persistence of CFCs.
2. Convention on International Trade in Endangered Species (CITES, 1973)
- Target: trade in endangered plants and animals.
- Strengths: raises awareness, reduces illegal trade.
- Weaknesses: enforcement varies by country.
3. Convention on Biological Diversity (CBD, 1992)
- Target: biodiversity protection and sustainable use.
- Strengths: integrates biodiversity into national policies.
- Weaknesses: limited enforcement, biodiversity loss continues.
4. Paris Agreement (2015)
- Target: limit global warming to below 2°C.
- Strengths: near-universal participation, flexible national commitments.
- Weaknesses: voluntary targets, uneven progress.
Evaluating International Environmental Law
When discussing treaties in ESS exams, always consider:
- Effectiveness: Did it reduce emissions or protect biodiversity?
- Equity: Are responsibilities shared fairly between developed and developing nations?
- Enforcement: Are rules binding, or voluntary?
- Public awareness: Did it raise global consciousness of the issue?
Case Studies for ESS Exams
- Montreal Protocol: successful global action on ozone depletion.
- Paris Agreement: ambitious but slow progress on climate change.
- CITES and ivory trade bans: mixed effectiveness due to illegal markets.
International Law in ESS Exams
Paper 1
HL students may face data questions on treaty participation or emission trends.
Paper 2
Possible essay-style questions include:
- “Evaluate the effectiveness of international environmental law in addressing global issues.”
- “Discuss the strengths and weaknesses of the Montreal Protocol and Paris Agreement.”
Exam Tips
- Use named treaties. General answers get fewer marks.
- Balance successes and failures. Show critical evaluation.
- Connect to ESS themes. Link law to sustainability, economics, and ethics.
FAQs
1. Do I need to know the details of every treaty?
No. Focus on a few major agreements (Montreal, Paris, CITES, CBD). Learn their aims, successes, and weaknesses.
2. Will I need to know dates?
Yes, knowing the year of adoption strengthens your answers.
3. Is this only tested at HL?
Yes. SL students do not get law-specific questions, but they may use treaties as case studies if helpful.
Conclusion
International environmental law is an important part of the ESS HL syllabus because it demonstrates how nations cooperate to tackle global problems. By learning key treaties, evaluating their effectiveness, and connecting them to sustainability, you’ll be ready for exam questions in the 2026 first assessment.
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