Finite and renewable resources

A resource is a material that people use. Resources can be classified by comparing how quickly they are replaced with how quickly people use them.

Finite resources are limited in amount or are replaced so slowly that they cannot be replenished on a human timescale. If people continue to use them, the available supply will eventually run out. Many fuels, metal ores and other raw materials obtained from the Earth, oceans and atmosphere are finite resources.

For example, fossil fuels form over millions of years, but people use them much faster than they form. Their supply cannot be replaced quickly enough for continued human use.

Renewable resources are naturally replaced or can be regrown over relatively short timescales. They can remain available for continued use if they are managed properly. For example, wood can be renewable when trees are regrown to replace those that are harvested. However, if trees are removed faster than they grow, the supply can still be depleted.

Classifying a resource

To decide whether a resource is finite or renewable, consider how it forms, how quickly it is replaced and how quickly it is used. A resource replaced only over an extremely long period is finite on a human timescale. A resource replaced over a relatively short period is renewable, but it must be used at a rate that allows its supply to recover.

Natural, agricultural and synthetic products

Many useful products come from materials found in nature. A natural product does not have to be used exactly as it is found: it can be collected and processed into a form that people can use.

Cotton, wool, leather, wood, natural rubber and plant oils are natural products. Cotton comes from plants, wool from animals, leather from animal hides and wood from trees. Natural rubber is obtained from the latex of rubber trees, while plant oils are extracted from plants.

Agricultural production

Natural products do not have to be collected only from wild sources. Agriculture increases the supply of biological materials by growing crops and trees and raising animals. These sources provide food, timber, fibres and materials that can be used as fuels.

For example, cotton can be grown for its fibres, and trees can be grown for timber or natural rubber. Agricultural production therefore reduces reliance on supplies gathered from the wild.

Synthetic alternatives

Chemistry allows materials to be made by changing raw materials into new products. These synthetic products can supplement natural products or replace them when natural supplies are limited, demand is high, or different properties are needed.

For example, polyester and nylon are synthetic fibres, and synthetic rubber can be used instead of natural rubber for some purposes. Fuels can also be manufactured from raw materials rather than obtained only from naturally occurring fuel supplies. Synthetic products still require raw materials, but they can reduce reliance on a particular naturally occurring supply.

Sustainable development

People rely on Earth’s resources for food, warmth, shelter, transport, energy and materials. Sustainable development means meeting people’s needs today without reducing the ability of future generations to meet their own needs.

This requires more than considering what a resource provides now. Resources must also be obtained, processed and used responsibly, so that meeting present needs does not unnecessarily reduce what will be available in the future.

Chemistry and sustainable development

Chemistry can improve agricultural processes so that more useful food is produced from the resources used. It can also improve industrial processes so that less raw material and energy are needed to make a given amount of product. Using resources more efficiently reduces the amount needed to meet present demand.

Chemistry also helps create new products that reduce pressure on scarce resources, for example by using more readily available materials in their place. These approaches balance the benefits people need now with the availability of resources for the future.

Resource data interpretation

Resource data can show how much of a material is used or available, and how those quantities compare or change. A useful judgment identifies what the data show, describes the size of the difference and avoids claiming more than the data support.

Reading and comparing resource data

Before reading a value, check what the chart, graph or table measures. Look at its title, category labels, units and, where relevant, the time period. On a graph, check the scale of each axis: equal-looking steps do not always represent the same numerical increase.

Compare values that measure the same quantity in compatible units. A difference in tonnes, for example, tells you how much more one category contains than another. A ratio tells you how many times larger one value is, which can make the significance of the difference clearer.

To identify a trend, follow values for the same quantity over time. They may rise, fall, remain roughly constant or change direction. Describe the time period as well as the pattern, because a trend over one interval may not continue over another.

Orders of magnitude in resource data

An order of magnitude represents an approximate factor of ten. If one quantity is about ten times another, it is about one order of magnitude larger; if it is about 100 times larger, it is about two orders of magnitude larger. A quantity that is twice another is larger, but not by an order of magnitude.

For example, suppose data show that resource A has an available quantity of 2 million tonnes and resource B has 20 million tonnes. B has 18 million tonnes more than A, but the ratio gives another perspective: B has ten times as much, so it is one order of magnitude larger. This is a substantial relative difference, not just a small increase.

Drawing conclusions from resource data

Base a conclusion on the quantity actually shown. A graph of annual resource use can show whether use is rising or falling, but it does not by itself show how much of the resource remains available. Similarly, a difference between categories does not by itself explain what caused it.

State the pattern or comparison using values and units, then explain what it means for resource use or availability within the limits of the data.