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Home › Academics & Courses › IB Diploma › ESS
IB ENVIRONMENTAL SYSTEMS AND SOCIETIES
IB ESS tutor for the new 2026 course, SL and HL
Environmental systems and societies (ESS) asks you to read a data table like a scientist and weigh a policy like a citizen, sometimes in the same question. IB Learning Star offers online IB ESS tutoring for the Diploma course first assessed in 2026, at SL and HL. One-on-one lessons run live on Google Meet at times that suit your time zone, and your first class is a free trial.
SL and HL
New 2026 course
One-on-one on Google Meet
Free trial class
WHERE MARKS GO
Why strong ESS students still lose marks
ESS rewards students who connect science and society. The marks leak in a few predictable places.
Answering Paper 1 from memory instead of from the data.
The case study is unseen. Students who start writing everything they know about the topic, and use the figures only as decoration, lose the marks that sit in the numbers.
An investigation question that is too wide.
The individual investigation has a 3,000-word limit. A question about “pollution” or “climate change” cannot be answered in that space, and a method that someone else cannot repeat cannot earn the method marks.
At HL, treating the lenses as extra reading.
Environmental law, economics and ethics are examined, and the best answers use them to explain why a strategy succeeds or fails.
Essays that list facts.
The top band of the Paper 2 essay markband asks for balanced, insightful analysis, precise terms, examples that are explained and a conclusion supported by evidence. A page of correct facts with no weighing of them stays in the lower bands.
Treating the strategy criterion as an afterthought.
One of the six investigation criteria asks you to explain a tension between perspectives, such as economic against environmental, around a strategy linked to your question. Students who leave it to the last page lose four marks that are easy to earn.
We work on these from the first lesson, using your own class notes, your recent answers and the case studies your school has chosen.
Our tutors are certified IBDP tutors or have completed IBDP training, at least IB Category 2 workshops, and they teach in IB schools.
This page describes the course first examined in 2026. We will update it if the IB publishes a new guide.
THE COURSE
What the new ESS course covers: eight topics and, at HL, three lenses
ESS is an interdisciplinary course. It draws on ecology, chemistry, geography, economics, law, philosophy and other subjects, and it sits in both the individuals and societies group and the sciences group. A student can study it in either group, or in both. Three key concepts run through everything: perspectives, systems and sustainability.
The recommended teaching time is 150 hours at SL and 240 at HL. The topic hours are below.
TOPIC · SL HOURS · HL HOURS
1
Foundation (perspectives 3, systems 5, sustainability 8)
16
SL hours
16
HL hours
2
Ecology
22
SL hours
35
HL hours
3
Biodiversity and conservation
13
SL hours
26
HL hours
4
Water
12
SL hours
25
HL hours
5
Land
8
SL hours
15
HL hours
6
Atmosphere and climate change
10
SL hours
23
HL hours
7
Natural resources
10
SL hours
18
HL hours
8
Human populations and urban systems
9
SL hours
15
HL hours
HL lenses (environmental law 5, environmental economics 7, environmental ethics 5)
none / 17
Experimental programme (practical work 30, collaborative sciences project 10, individual investigation 10)
50 / 50
Total
150 / 240
quadrats
transects
capture-recapture
surveys
secondary data
Practical work is built into the course. It includes fieldwork techniques such as quadrat sampling, transects and the capture, mark, release and recapture method, surveys and interviews, and work with secondary data. The skills run through four tools (experimental techniques, technology, mathematics, and systems and models) and a three-part inquiry process (exploring and designing, collecting and processing data, concluding and evaluating).
HL students study the same core as SL students, plus extra content inside each topic and the three lenses. The HL material is not simply “more”. It asks you to connect ideas across topics and to judge solutions using legal, economic and ethical reasoning.
Every student also takes part in the collaborative sciences project, which the course counts within the 50 hours of experimental work.
PAPER 1
Paper 1: a data case study you have not seen
Paper 1 gives you a range of data in different forms, such as tables, graphs, maps and short texts, about one case study you have not seen before. Every question is compulsory and is based on analysing and evaluating that data. At SL the paper lasts 1 hour and has 35 marks. At HL it lasts 2 hours and has 70 marks. Paper 1 is 25% of the grade at SL and 30% at HL.
A worked case: one invented lake, four questions
Here is a case we invented for this page. It is not an IB case, and the questions and marks are our own. A lake has a single inflow that drains farmland. Samples were taken at that inflow every two years.
Year | Nitrate (mg per litre) | Dissolved oxygen (mg per litre) |
|---|---|---|
2019 | 1.2 | 8.1 |
2021 | 2.5 | 7.4 |
2023 | 4.0 | 6.2 |
2025 | 6.1 | 5.0 |
Question 1. Describe the trend in nitrate. Question 2. Calculate the percentage change in dissolved oxygen from 2019 to 2025. Question 3. Suggest how rising nitrate could lower dissolved oxygen. Question 4. Evaluate one strategy to reduce nitrate entering the lake.
1
READ FIRST
Step 1. Read before you write.
Check the units and the years. Nitrate is rising and oxygen is falling. Note that there are only four readings at one site.
2
DESCRIBE · CALCULATE
Step 2. Match the answer to the command term.
“Describe” means a detailed account: nitrate rises at every reading, from 1.2 to 6.1, and each two-year rise is bigger than the last (1.3, 1.5, then 2.1). “Calculate” means show the working: (8.1 minus 5.0) divided by 8.1, times 100, is 38%, a fall.
3
SUGGEST
Step 3. Give reasons for “suggest”.
More nitrate feeds algae, which grow fast. When the algae die, bacteria that break them down use up oxygen. This is eutrophication.
4
EVALUATE
Step 4. Weigh for “evaluate”.
A strip of vegetation along the inflow can trap nutrients cheaply, but it takes land out of farming and works only where the strip is wide enough. A limit on fertiliser use tackles the cause, but it can cut farm income, so farmers may oppose it. Close with a judgement: with four readings at one site, the data cannot prove that nitrate is the only cause of the oxygen fall, so any strategy should come with continued monitoring.
PAPER 2
Paper 2: short answers, data questions and essays
Paper 2 has two sections. Section A has short-answer and data-based questions, 40 marks at both levels. Section B has structured essay questions of 20 marks each. At SL you answer one essay from a choice of two (60 marks in total, 2 hours). At HL you answer two essays from a choice of three (80 marks in total, 2 hours 30 minutes). Paper 2 is 50% of the grade at both levels.
SECTION A
40
marks, short answers and data
SECTION B
20
marks per essay
SL · 1 of 2 essays
60 marks · 2 hours
HL · 2 of 3 essays
80 marks · 2 h 30
50% of the grade at both levels
The last part of each essay is marked with a markband out of 9. The higher bands reward knowledge that is linked across the syllabus, precise use of ESS terms, examples that are well explained and show some originality, balanced and insightful analysis, and a conclusion supported by evidence that reflects critically on the issue. At HL the markband also covers the lenses.
Our routine has three steps. First, build a bank of examples you can explain in detail, such as a named place, a policy and its results, rather than a list of headlines. Second, practise the structure of each essay part: define, explain with a cause, give an example, weigh two sides, then judge. Third, practise writing under time with questions you have not seen, so that the judgement is written, not saved for “if there is time”.
1
define
2
explain with a cause
3
give an example
4
weigh two sides
5
judge
HIGHER LEVEL
The HL lenses: law, economics and ethics
HL students study three lenses over 17 hours. They are a way of asking why a strategy works, who pays for it and whether it is fair.
Environmental law covers how rules are made and enforced, from local rules to international agreements, and what happens when agreements are hard to enforce. Environmental economics covers market failure, the polluter-pays idea, the value of ecosystem services and the link between economic growth and environmental harm. Environmental ethics asks how far humans have a moral duty towards the environment, and how different ethical positions lead to different solutions.
In an essay on a water scheme, for example, a lens answer might say that a tax on water use corrects a market failure but raises a fairness question for poorer households. That one sentence uses economics and ethics together, which is what the higher bands look for.
In lessons we show you where each lens plugs into the eight topics, so that you are not learning three extra subjects.
THE INTERNAL ASSESSMENT
The individual investigation (the ESS internal assessment)
The internal assessment is one task: an individual investigation of your own research question, written up in a report of up to 3,000 words. It is marked out of 30 and is 25% of the grade at SL and 20% at HL. The requirements are the same at both levels. You collect and analyse data, primary or secondary, qualitative or quantitative. Your teacher marks it and the IB moderates it.
30
marks
25% / 20%
of the grade, SL / HL
3,000
words at most
6
criteria
up to 3
students may plan together
Six criteria are used. Research question and inquiry, strategy and method are each worth 4 marks. Treatment of data, analysis and conclusion, and evaluation are each worth 6.
Research question and inquiry
4
marks
Strategy
4
marks
Method
4
marks
Treatment of data
6
marks
Analysis and conclusion
6
marks
Evaluation
6
marks
A worked narrowing: from a topic to a question you can answer
“plastic pollution”
→
fragments per m² vs distance from the slipway
1
Start broad: “plastic pollution”. That cannot be answered in 3,000 words. Narrow it to something you can measure in a place you can reach: how the number of plastic fragments per square metre on one beach changes with distance from the nearest slipway. Now test it. Can you describe the method so that someone else could repeat it, with quadrat size, number of samples and how you choose where to place them? Can you collect enough data in the time you have? If so, the question passes the method test.
2
Then the strategy criterion. Find a strategy linked to your question, for example a local beach-clean scheme or a ban on single-use plastics. Then explain one tension between perspectives that results from it. A clean-up scheme might satisfy environmental and tourism interests, while a ban might put costs on small shops. The tension must be explained, and naming it is not enough.
You may work with others on the question and method, in groups of up to three, but your data, your report and your authoring must be your own. Your teacher reads one draft and gives advice, but does not edit it. The same piece of work cannot be used for the Extended Essay. In lessons we help you test a question, plan a repeatable method and check your report against the six criteria, and you make the choices yourself.
Assessment at SL and HL
The weights add to 100% at each level.
SL
Paper 1, data case study, 1 hour, 35 marks:
25%
Paper 2, 2 hours, 60 marks:
50%
Individual investigation, up to 3,000 words, 30 marks:
25%
HL
Paper 1, data case study, 2 hours, 70 marks:
30%
Paper 2, 2 hours 30 minutes, 80 marks:
50%
Individual investigation, up to 3,000 words, 30 marks:
20%
HOW IT WORKS
What an IB ESS lesson looks like
The first lesson is a diagnostic. You show us a recent Paper 1 or Paper 2 answer, or your investigation question and method, and we find where the marks went: in the reading of the data, in the use of examples or in the structure.
After that, each lesson takes one task. It might be a case study with a data table, read cold and answered against the clock. Or it might be an essay plan, a check of a research question, a systems diagram or a run-through of a HL lens in a short essay. You leave with a short exercise before the next lesson, so the habit builds between sessions.
Students writing an Extended Essay on an environmental topic, or working on Theory of Knowledge questions that ESS raises, can ask us to link those with the course.
Lessons are one-on-one on Google Meet, in your time zone.
FAQ
What ESS students and parents ask us
What does ESS stand for in the IB?
−
ESS stands for environmental systems and societies. It is an IB Diploma course that studies environmental systems and how societies use, change and manage them.
Is ESS a science or a humanities subject?
+
Both. The IB lets students count ESS in the individuals and societies group, in the sciences group, or in both. If it counts in both, the student can then choose an extra subject from any group. Your school decides how it is set up.
Is ESS the easiest IB subject?
+
No subject is easy to score well in, and ESS has its own difficulty. It covers a wide range of content, it needs you to read unseen data, and it asks for balanced judgements as well as facts. Many students find the content approachable and then lose marks on application. We do not quote grade statistics here, because they change each session and between SL and HL.
What is new in the 2026 course?
+
There is now an HL course with three extra lenses (environmental law, economics and ethics). Both levels have a new topic list, a Paper 1 built around a data case study, a Paper 2 with short answers and essays, and an individual investigation marked on six criteria. If you use older books or past papers, check which course they cover.
What is the difference between SL and HL?
+
HL has 240 recommended hours instead of 150, extra content inside each topic, and the three lenses. HL Paper 1 is 2 hours and 70 marks, and HL Paper 2 is 2 hours 30 minutes with two essays. The individual investigation is the same task at both levels, but it is 25% of the grade at SL and 20% at HL.
Is Paper 1 based on a case study I can revise?
+
No. The case study is previously unseen, so you cannot learn it. What you can learn is how to read data, use the command term, and apply the ideas from the syllabus to a new situation.
How many case studies and examples do I need to know?
+
The guide does not set a number. A small bank of examples that you know well, with places, dates, actions and results, works better than a long list that you know loosely. We help you build it.
Can I use the same work for the investigation and the Extended Essay?
+
No. The same piece of work cannot be used for both, and an Extended Essay must not be based on the research question of your ESS investigation.
Can I do the investigation with friends?
+
You can plan the question and method together in a group of up to three. Your data, your report and the writing must be your own.
Who teaches the lessons?
+
Your tutor is a certified IBDP tutor or has completed IBDP training, at least IB Category 2 workshops, and teaches in an IB school. We match the tutor to your course and level.
Will lessons fit my time zone?
+
Yes. Lessons are one-on-one on Google Meet and we plan them around your school day, wherever you are.
How do I start?
+
Book a free trial class. We use it to see where you are, then suggest a plan and a lesson schedule.
Start with a trial class for IB ESS
Tell us your level (SL or HL), your exam year and the part that worries you most: Paper 1, Paper 2, the investigation or the HL lenses. We will plan the first lesson around it.
