IB ESS — Sustainability

Evidence of improvement Lower resource demand and emissions. Habitats protected or restored. Harvesting within replacement rates, with ecosystems protected.

Evidence of pressure Resource depletion and habitat loss. More pollution or greenhouse-gas emissions. Demand rising above nature’s capacity to supply resources or absorb wastes.

How to judge sustainability Evidence for → evidence against → supported judgement. Example: renewable electricity is a benefit, but habitat destruction is a cost. Explain both before concluding.

Environmental: nature Protect ecosystems and biodiversity. Use resources sustainably and reduce pollution.

Social: people Support health, education, fair access and community. Help societies and cultures survive.

Economic: livelihoods Keep goods, services, jobs and income available into the future. Protect the resources they depend on.

Weak vs strong models Weak: the three pillars overlap. Strong: the economy is inside society, and both are inside the environment. Nature supports them.

Forest example Capital: the forest already there. Income: new growth. Harvest no faster than replacement, while protecting habitats, soil and water.

Renewable does not mean unlimited Fish and trees can reproduce or regrow. They can still be depleted if use is too fast or ecosystems are damaged.

Replacement time matters Crops may regrow in months; forests take much longer. Peat forms very slowly. Coal and oil are not replaced on human timescales.

Equity {{Equity|fair access to opportunities and support}} means people are not left out. Example: affordable health care helps low-income families get treatment.

Culture must last too Pass languages, beliefs, spiritual practices and knowledge to the next generation. Example: teaching children through their community’s language helps keep it in use.

A bakery makes the link visible Healthy soil and water → wheat grows → flour reaches the bakery → people have food and jobs.

What helps an economy last? Reliable transport, energy and banking help businesses work. A mix of jobs and savings helps a community cope if one business closes.

The three aims Economic stability: lasting livelihoods. Social equity: fair opportunities. Ecological integrity: functioning ecosystems.

Brundtland Report, 1987 Our Common Future set out this definition and linked development with social, economic and environmental needs.

Example: a new water supply Safe, affordable water improves lives. Taking too much from a river can damage ecosystems and future supplies. Judge both effects.

Possible pressures Habitat loss, overexploitation, pollution, invasive species and climate change can weaken ecosystems.

Named example: northern cod Newfoundland, Canada: overfishing helped collapse the stock. A fishing moratorium began in 1992. Recovery was slow for decades; the commercial fishery reopened in 2024 under limits.

Explain the cause and effect Excessive catches → fewer fish remain → replacement cannot keep up. The collapse harms nature, fishing communities and the economy.

Why GDP can mislead Cut forest → sell timber → GDP rises. Habitat and natural capital can still decline. GDP does not automatically subtract that damage.

Worked example GDP: $500 billion. Resource depletion: $40 billion. Pollution damage: $35 billion. Green GDP = 500 − 40 − 35 = $425 billion.

Measures are different GDP per person: GDP ÷ population, an average. Gross National Happiness: considers well-being across several domains. No single measure proves overall sustainability.

Simple example A factory supplies goods to many people, but nearby low-income families face most of its pollution. Unequal harm and little influence over decisions can make this unjust.

Named local and global examples Local: Bhopal, India, 1984—nearby communities suffered from a toxic gas leak. Global: exported plastic waste can place environmental burdens on communities receiving poorly managed waste.

Make the explanation complete Identify the affected people, the harm and why its distribution or decision-making is unfair.

Why poverty can reinforce itself Low income → unsafe water → illness → less school or paid work → low income.

How conflict can develop Unequal access or scarcity → competition and grievances → tension or conflict. Example: upstream and downstream countries may disagree over water extraction or dams on a shared river such as the Nile.

One problem, different actions Individual: reuse a bottle. Business: reduce packaging. City: improve waste collection. Global: coordinate action on pollution crossing borders.

Scale changes the judgement A country can have an ecological reserve while its high-consuming lifestyle would be impossible for everyone on Earth. State the scale before drawing a conclusion.

Use all three pillars Environmental: emissions, biodiversity, footprints and biocapacity. Social: health, education and resource access. Economic: employment, income and economic output.

Living indicators Sensitive species may decline under pollution; tolerant species may become more common. Identify which kind of organism you are using and check other causes too.

Read a change carefully Waste falls from 2 kg to 1 kg per student: improvement on that indicator. It does not prove that every part of the school is sustainable.

Why a footprint increases Greater material consumption, fossil-fuel emissions and resource-intensive diets can increase demand. Explain the activity → resource use or emissions → larger footprint.

Why a footprint can fall Lower consumption, repair, reuse, efficiency and lower-emission energy can reduce demand. Check the size of the change and any other impacts.

Total vs per person Total footprint = footprint per person × population. 2 gha per person × 1,000 people = 2,000 gha. Total demand can rise even while demand per person falls.

How the estimate is built Record resource demand and emissions. Use productivity data to convert each component into area. Standardise and add the components. Do not directly add different quantities before converting them.

A balanced evaluation Strength: common units make comparisons easier. Limit: estimates depend on data and assumptions; some impacts are not fully represented. Use it alongside other indicators.

Carbon footprint Includes emissions associated with energy, transport, manufacturing and food. Measured in kg or tonnes of {{CO₂ equivalent (CO₂e)|a common unit comparing the warming effect of different greenhouse gases}}.

Water footprint Includes direct use and water used to grow or make what you buy. Example: water used to grow cotton for a T-shirt. Measured in litres or cubic metres. Local water scarcity affects the impact.

Choose a specific strategy Reuse suitable treated water → less fresh water needed. Lower-emission electricity → fewer greenhouse-gas emissions. Name the method and explain the pressure it reduces.

Reserve Footprint < biocapacity: supply exceeds demand in this measure. Reserve = biocapacity − footprint. Equality means demand matches supply.

Deficit Footprint > biocapacity: ecological deficit. Demand exceeds the area’s measured supply. Trade may draw on ecosystems elsewhere; depletion or waste accumulation may also occur.

What changes biocapacity? Habitat restoration and healthy productive land can support supply. Erosion, pollution and loss of productive land can reduce it. If population grows while total supply stays fixed, supply per person falls.

Biocapacity vs carrying capacity Biocapacity: ecological supply, expressed in gha. Carrying capacity: number of individuals an area can support under given conditions.

Why it helps Many volunteers → more observations, places and years. It can support local decisions and wider research while increasing participation.

What needs checking? Misidentification, uneven sampling and inconsistent methods can introduce error or bias. Training, shared instructions and expert checks improve reliability.

Evaluation example A class bird count adds useful observations when everyone follows the same rules. More data does not automatically mean more accurate data.

Uses Explain relationships, compare places, track change and guide plans. Example: nested circles communicate dependence on nature.

Limitations Missing detail, uncertain data, assumptions and values affect results. A global model may not specify local policies. Use several tools with local evidence.

Example: clean water Goal: clean water and sanitation. Target: safe, affordable drinking water for everyone. Indicator: proportion using safely managed drinking-water services.

Connections and trade-offs Better water access can improve health and education. A jobs project may also increase emissions. Explain which goals it supports or puts under pressure.

Uses and limits Shared goals help coordinate action in all countries. Funding, data, participation and locally suitable policies are still needed.

Climate change Greenhouse-gas emissions change Earth’s energy balance.

Biosphere integrity Biodiversity and ecosystem functions support Earth’s resilience.

Land-system change Converting forests and other land changes ecosystem functions.

Freshwater use Changes to rivers, groundwater and soil moisture affect ecosystems.

Biogeochemical flows Excess nitrogen and phosphorus disrupt nutrient cycles.

Ocean acidification Carbon dioxide absorbed by seawater changes its chemistry.

Atmospheric aerosol loading Tiny airborne particles affect climate and other processes.

Stratospheric ozone depletion Ozone loss reduces protection from ultraviolet radiation.

Novel entities Human-made substances, such as plastics and synthetic chemicals, can disrupt ecosystems.

Inside the hole: social shortfall Basic needs are not met: food, water, health, education or housing. The inner limit is the social foundation, linked to the SDGs.

Outside the ring: ecological overshoot Environmental pressure exceeds limits. The outer limit is the ecological ceiling, based on planetary boundaries.

Regenerative design Support natural renewal and work within ecological cycles. Example: compost appropriate biological waste and restore habitats.

Distributive design Share opportunities and benefits fairly. Example: fair wages or community ownership. The framework guides aims; local policies still need to be designed.

Three principles Eliminate waste and pollution. Circulate products and materials. Regenerate nature.

Phone example Design a durable, repairable phone → replace worn parts → reuse working parts → recover materials when repair is no longer suitable.

Technical vs biological cycles Technical: repair, reuse and recover materials such as metals. Biological: return suitable nutrients safely to natural cycles.

What does decoupling mean? Reduce the link between economic activity and resource use or environmental harm. Circular strategies aim to help, but still need energy, finance and suitable technology.

Exam tips

• Define the term, then apply it to the example or data.
• Link an action to a consequence: what changes, and why?
• Check units, dates and whether figures are total or per person.
• For an evaluation, weigh evidence on both sides and give a supported judgement.