Earth's resources become the energy and materials you use

1. A natural resource is a material or feature of the Earth that people use to meet their needs.
2. People rely on resources for warmth, shelter, food and transport.
3. Natural resources, supplemented by agriculture, provide food, timber, clothing and fuels.
4. Resources are taken from the Earth's crust, the oceans and the atmosphere.
5. These raw materials are then processed into useful energy and materials.
6. Some resources, including fossil fuels and metal ores, exist in limited amounts.

Agricultural and synthetic products supplement or replace natural products

1. Food: agriculture supplements wild food by growing crops, rearing livestock and farming fish.
   1. Fish farms can reduce the pressure on wild fish populations.
2. Timber: managed plantations supplement timber taken from natural forests.
   1. Trees can be replanted after harvesting if the forest is managed responsibly.
3. Clothing: cotton and wool are agricultural products spun into natural fibres.
   1. Synthetic fibres such as polyester and nylon can supplement or replace cotton and wool.
4. Materials: synthetic rubber can supplement or replace the natural rubber tapped from trees.
5. Fuels: crops grown for biofuels supplement fuels taken from finite resources.

Replacement rate separates finite resources from renewable resources

1. A finite resource is used up faster than it is replaced, so its supply will eventually run out.
2. Fossil fuels and metal ores are finite because they form far too slowly to replace what is extracted.
3. A renewable resource is replenished naturally at least as fast as it is used.
4. Sunlight and wind are renewable because using them does not reduce the future supply.
5. Timber and crops can be renewable, but only if they are replanted and given time to regrow.

Sustainable development meets present needs without removing future choices

1. Sustainable development meets the needs of people today without stopping future generations from meeting their own needs.
2. Using resources sustainably means not wasting finite raw materials and energy.
3. It also means using renewable resources no faster than they can be replaced.
4. Chemistry improves agricultural processes by raising food production or cutting the resources wasted.
5. Chemistry improves industrial processes by using fewer raw materials, less energy or making less waste.
6. A catalyst can let an industrial reaction run at a lower temperature, saving energy.
7. Chemistry also develops new products that supplement or replace those made from scarce natural resources.

Reading resource data: check the scale before you compare

1. Resource information is often given in charts, graphs and tables.
2. First identify the resource, the time period and the units used.
3. Check the scale carefully, because axes may rise in thousands, millions or unequal steps.
4. Read the values accurately and only compare quantities measured in the same units.
5. An order of magnitude is a factor of ten.
6. A quantity ten times larger is one order of magnitude larger.
7. A quantity one hundred times larger is two orders of magnitude larger, because $100=10^2$.
8. A quantity one thousand times larger is three orders of magnitude larger, because $1000=10^3$.
9. Worked example: Resource A is used at $4\times 10^6$ tonnes per year and Resource B at $4\times 10^3$ tonnes per year.
   1. Dividing the larger value by the smaller gives $\frac{4\times 10^6}{4\times 10^3}=10^3$.
   2. Resource A is therefore used one thousand times faster, a difference of three orders of magnitude.

Judging whether resource use can continue

1. A large supply does not prove a resource is renewable, because it may never be replaced after use.
2. A renewable resource can still be used unsustainably if it is consumed faster than it is replaced.
3. For a finite resource, compare the amount available with the rate of extraction.
4. For a renewable biological resource, compare the rate of harvesting with the rate of regrowth.
5. Use orders of magnitude to decide whether a numerical difference is small or large.
6. A strong conclusion names the resource, states whether its use looks sustainable, and quotes data to back the judgement.