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AQA A-level Environmental Science (7447) · Sustainability
Mini-Lesson

Sustainability

Can humanity meet its needs without wrecking the systems it depends on? This lesson covers sustainable development, the ecological footprint, planetary boundaries and the circular economy.

You will calculate a footprint ratio and a recycling rate. Answer the questions and collect ⭐.

Definition

Sustainable development

The Brundtland Report (Our Common Future, 1987) defined sustainable development as development that meets the needs of the present without compromising the ability of future generations to meet their own needs.

Check

Sustainable development

1The Brundtland definition of sustainable development emphasises meeting present needs while:
Footprint

Ecological footprint and biocapacity

The ecological footprint is the area of land and sea needed to supply a population’s resources and absorb its waste, measured in global hectares (gha). Biocapacity is the area actually available. If the footprint exceeds biocapacity, the population is in ecological overshoot.

Calculate

Your turn — footprint ratio

1A country has an ecological footprint of 2.8 gha per person and a biocapacity of 1.6 gha per person. Calculate how many times its footprint exceeds its biocapacity, to 2 decimal places.
× biocapacity
Hint: ratio = footprint ÷ biocapacity = 2.8 ÷ 1.6.
Boundaries

Planetary boundaries

The planetary boundaries framework (Rockström and colleagues, 2009) identifies nine Earth-system processes — including climate change, biodiversity loss, and nitrogen and phosphorus flows — each with a threshold defining a safe operating space for humanity. Crossing a boundary risks abrupt, large-scale change.

Check

Planetary boundaries

2The planetary boundaries framework defines, for each Earth-system process, a:
Circular economy

The circular economy

A linear economy follows "take–make–dispose." A circular economy keeps materials in use through reduce, reuse, repair and recycle, cutting waste and resource extraction.

Calculate

Your turn — recycling rate

2A city recycles 320 tonnes of the 800 tonnes of waste it produces. Calculate its recycling rate as a percentage.
%
Hint: rate = (320 ÷ 800) × 100.
Sort it

Which category?

Sort each item into the correct category.

🔄 Circular economy

➡️ Linear economy

🌐 Planetary boundary

Match

Term to meaning

Match each term to its meaning.

Statement
Answer
Recap

The big ideas to know

Sustainable development: Brundtland (1987): meet present needs without harming future generations

Ecological footprint: Demand (gha) vs biocapacity; overshoot when footprint is greater

Planetary boundaries: Nine processes with safe thresholds (Rockström et al., 2009)

Circular economy: Reduce, reuse, repair, recycle — not take–make–dispose

Sustainability means living within the planet’s renewable limits. Press Finish.

🏆

Mini-lesson complete!

⭐⭐⭐

You've worked through Sustainability. 🎉

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