Earth's Resources and Sustainable Development Notes
AQA GCSE Chemistry: Revision notes
Key facts
- Finite resources will run out; renewable resources are replenished at a similar rate to use.
- Sustainable development meets today's needs without stopping future generations meeting theirs.
- A life cycle assessment covers four stages: extraction and processing, manufacture and packaging, use, and disposal.
- LCAs are not fully objective: values for pollutant effects need value judgements.
- Reduce, reuse and recycle; metals can be melted and recast.
Finite and renewable
Resources are finite (they run out) or renewable (replenished as fast as we use them).
Humans use natural resources, supplemented by agriculture, for warmth, shelter, food and transport. Many natural products are replaced by agricultural and synthetic ones, such as synthetic fibres replacing natural fibres.
To classify a resource, ask whether nature can replace it as fast as we use it.
| Meaning | Examples | |
|---|---|---|
| Finite | Will eventually run out | Fossil fuels, metal ores |
| Renewable | Replenished at a similar rate to use | Timber, wind energy |
Meaning
- Finite:
- Will eventually run out
- Renewable:
- Replenished at a similar rate to use
Examples
- Finite:
- Fossil fuels, metal ores
- Renewable:
- Timber, wind energy
Which of these is a finite resource?
Sustainable development
Meeting the needs of today without harming the ability of future generations to meet theirs.
Sustainable development means meeting the needs of current generations without compromising the ability of future generations to meet their own needs.
- Sustainable developmentmeets present needs without harming future generations
What does sustainable development aim to protect?
Life cycle assessment
An LCA assesses a product's environmental impact across four stages.
A life cycle assessment (LCA) assesses the environmental impact of a product. Transport and distribution at each stage are included.
LCAs compare the true environmental cost of different products, not just the impact of using them.
- 1
Extracting and processing
raw materials
- 2
Manufacturing and packaging
making the product
- 3
Use and operation
during the product's lifetime
- 4
Disposal
at the end of its useful life
How many stages does a life cycle assessment cover?
Is an LCA objective?
No: some parts are measurable, but judging the effects of pollutants needs value judgements.
Use of water, resources and energy, and the amount of some wastes, can be fairly easily put into numbers. Giving numerical values to the effects of pollutants needs value judgements.
Selective or abbreviated LCAs can be misused to reach a predetermined conclusion, for example comparing plastic and paper shopping bags.
Easy to quantify
- Water, resource and energy use
- Amount of some wastes
Needs value judgements
- Effects of pollutants
- Which stages to include
Why is an LCA not fully objective?
Reduce, reuse, recycle
Reduce how much we use, reuse materials and recycle them.
Ways of reducing the use of limited resources are reduction in use, reuse of materials and recycling.
Metals can be recycled by melting and recasting them into new products, saving both the raw material and the energy needed to extract new metal. Aluminium drink cans are an example.
- 1
Reduce
use less in the first place
- 2
Reuse
use the item again
- 3
Recycle
melt and recast metals into new products
How can metals be recycled?
Try an exam question
Describe the four stages assessed in a life cycle assessment (LCA) of a product.
[4 marks]
- [1]Extracting and processing raw materials.
- [1]Manufacturing and packaging.
- [1]Use and operation during its lifetime.
- [1]Disposal at the end of its useful life.
That's the notes covered.
Carry on to the next subtopic.