Coaching Centre
Renewable and non-renewable resources
What a natural resource is, the four spheres of the Earth that resources come from, renewable versus non-renewable resources and why the time scale matters, how renewable resources can still be used up, and reducing, reusing and recycling.
In the early 1990s, the cod fishery off Newfoundland in Canada was one of the richest in the world. Fish had been caught there for 500 years, and cod breed quickly, so they seemed endless. Then in 1992 the catch simply wasn't there. About 35 000 people lost their jobs overnight, and more than 30 years later the cod still haven't fully come back. Fish are a renewable resource. That didn't stop them running out.
What is a resource?
A natural resource is anything from the Earth that people use: to eat, to build with, to make things from or to supply energy. Scientists group them by which part of the Earth they come from. The Earth has four "spheres", and every resource comes from at least one of them.
| Sphere | What it is | Resources from it |
|---|---|---|
| Lithosphere | The rocky outer crust of the Earth | Coal, oil, natural gas, uranium, metal ores (iron, aluminium, copper, lithium, gold), sand, gravel, soil minerals, geothermal heat |
| Atmosphere | The layer of air around the Earth | Wind energy, oxygen, nitrogen (used to make fertiliser), sunlight passing through it |
| Hydrosphere | All the water: oceans, rivers, lakes, ice and groundwater | Drinking and irrigation water, hydro-electricity, tidal and wave energy, salt |
| Biosphere | All living things and where they live | Food crops, fish, timber, cotton, wool, medicines, biofuels |
Renewable or non-renewable?
A renewable resource is replaced naturally within a human lifetime, or is effectively unlimited. Sunlight, wind, flowing water, timber, fish and crops are renewable.
A non-renewable resource exists in a fixed amount, or forms so slowly that it won't be replaced in any time that matters to us. Coal, oil and natural gas are still forming today, deep underground, but it takes hundreds of thousands to millions of years. Every litre of gas you burn in a Bunsen burner is a litre less in the world. Metal ores and uranium are non-renewable too.
The key idea is time scale. Wood and coal are both made from plants. A eucalypt plantation can be harvested every 10 to 30 years, so timber is renewable. Coal took around 300 million years, so it isn't.
- Set the catch to 50 tonnes and run 30 years. Does the fishery last?
- Now try 150 tonnes. What happens to the stock, and how quickly?
- Find the biggest catch that never runs out. Then switch to the coal seam and try to find a rate that lasts for ever.
A renewable resource only stays renewable if we use it no faster than it is replaced. This is called using it sustainably: meeting our needs today without leaving less for people in the future. Forests cleared faster than they regrow, groundwater pumped faster than rain refills it, and soil washed away faster than it forms are all renewable resources being used unsustainably.
Reduce, reuse, recycle
The "three Rs" are ways to make non-renewable resources last longer. They are listed in order of how much they help:
- Reduce: use less in the first place. Turning off lights, taking shorter showers, buying fewer things and choosing products with less packaging means less needs to be mined, grown or made.
- Reuse: use something again for the same or a different job. Refillable bottles, second-hand clothes and repaired phones all save the energy and materials needed to make new ones.
- Recycle: break a material down and make it into something new. Recycling an aluminium can uses about 5% of the energy needed to make aluminium from bauxite ore, and aluminium can be recycled over and over without getting worse.
In NSW, the Return and Earn scheme pays 10 cents for most drink containers, and has collected well over 10 billion of them since 2017. Even small actions add up: if every Australian saved 1 litre of water a day, it would save about 27 million litres every day.
Test yourself
Which resource is non-renewable?
Gas takes millions of years to form.
Iron ore comes from the
It is mined from the rocky crust.
Timber is renewable but coal is not, even though both come from plants, because
The time scale decides it.
A fishery collapses when
Renewable resources need time to replace themselves.
Which of the three Rs saves the most resources?
Not using the resource at all saves the most.
Label the four spheres.
Sort the resources.
Wind energy comes from the . A resource that is replaced within a human lifetime is . Using a resource no faster than it is replaced is using it . The best of the three Rs is to .
Fish are described as a renewable resource, yet some fisheries have collapsed. Explain how this can happen, and describe one way to manage a fishery so that it lasts.
Fish are renewable because they breed and replace the ones that are caught. But if people catch them faster than they can reproduce, the population gets smaller each year, so even fewer young are produced. Eventually there are too few fish left to find mates and the fishery collapses, as the Atlantic cod did in 1992. One way to manage a fishery is to set a yearly catch limit (quota) that is less than the number of new fish produced each year, so the population stays large enough to keep replacing itself.