Resources

Natural resources are usually defined as 'renewable' or 'nonrenewable'. The first are resources that can be renewed or harvested regularly, such as timber for construction or linseed for linseed oil. They are only renewable as long as the right conditions for production are maintained. Depletion of the ozone layer is an example of how conditions for many renewable resources can be drastically changed. Most renewable resources have photosynthesis in common. It has been estimated that human society currently exploits about 40% of the earth's photo-synthetic activity (Brown etal., 1990).

Non-renewable resources are those that can only be harvested once. These are often referred to as 'stocks' (iron ore is an example); or else resources that are formed extremely slowly, such as crude oil. Many of these are seriously limited; metals and fossil oils are the most exploited, but in certain regions even materials such as sand and gravel are becoming scarce. The approximate reserves of raw materials are shown in Table 1.1. It is clear that some of the most important resources are in danger of being exhausted in the near future.

Table 1.1 Non-renewable resources used in the manufacturing of building materials

Raw material Reserve [years] Reserve base [years] Annual growth in consumption

Table 1.1 Non-renewable resources used in the manufacturing of building materials

Raw material Reserve [years] Reserve base [years] Annual growth in consumption

mineral

1999-2006[%]

1

Aggregate (sand, gravel)

Very Large

Very Large

2

Arsenic

20

30

6

3

Bauxite

141

180

6

4

Bentonite (Montmorillonite)

Large

Large

5

Boric salts

35

86

1

6

Brom

Large

Large

7

Cadmium

26

77

1

8

Chrome

Ca. 25

Ca. 40

8

9

Clay, for fired products

Very Large

Very Large

10

Cobalt

121

226

15

11

Copper

31

61

3

â– Table 1.1 (Continued )

Raw material mineral (continued)

Reserve [years]

Reserve base [years]

Annual growth in consumption 1999-2006[%]

12

Diatomite (silicious fossil meal)

Large

Large

13

Earth, for compressing

Very Large

Very large

14

Feldspar

Large

Large

15

Gold

17

36

1

16

Gypsum

Large

Large

17

Iron

95

219

10

18

Kaolin

Large

Large

19

Lead

20

42

1.5

20

Lime

Very Large

Very Large

21

Magnesium

Large

Very Large

22

Manganese

40

472

9

23

Mica

Very Large

Very Large

24

Mineral salt (sodium chloride)

Very Large

Very Large

25

Nickel

41

90

5

26

Perlite

Large

Large

27

Phosphate

124

345

0

28

Potash

Large

Large

29

Pumice

Large

Large

30

Quartz

Large

Large

31

Silica

Large

Large

32

Silver

14

29

3

33

Soda ash

Large

Large

34

Stone

Very Large

Very Large

35

Sulphur

21

53

1

36

Tin

22 (in 1999)

40 (in 1999)

4

37

Titanium

122

240

5

38

Vermiculite

Large

Large

39 Zinc 22 46 4.5

fossil

40

Coal

150

4.5

41

Natural gas

63

3

42

Crude oil

41

1.4

Reserve is defined as that part of the reserve base that could be economically extracted or produced at the time of determination. Reserve base includes those resources that are currently economic (Reserves), marginally economic, and some of those that are currently subeconomic. Both Reserve and Reserve base are estimated without growth in consumption. To sharpen the scenarios the annual growth in consumption 1999-2006 for the raw materials most threatened by depletion is also shown (U.S. Geological Survey, 2000 & 2007; British Petroleum, 2007)

Reserve is defined as that part of the reserve base that could be economically extracted or produced at the time of determination. Reserve base includes those resources that are currently economic (Reserves), marginally economic, and some of those that are currently subeconomic. Both Reserve and Reserve base are estimated without growth in consumption. To sharpen the scenarios the annual growth in consumption 1999-2006 for the raw materials most threatened by depletion is also shown (U.S. Geological Survey, 2000 & 2007; British Petroleum, 2007)

Fresh water is a vital resource which cannot be described as either renewable or non-renewable. The total amount of water is constant in a global perspective; but on a regional level, shortages of water are already critical, and likely to become more so given climate change. This is especially the case for potable water, which is essential not only in food production but also in many industries. Water is often used in industry in secondary processes; for example, as a cooling liquid, which is then returned to nature polluted and with a lower oxygen content.

Biodiversity and fertile soils are also to be seen as resources in the global ecosystem; and they too are only conditionally renewable. Their rate of exploitation or depletion is now in some cases so rapid that there is a danger that critical thresholds will be crossed (Muilerman and Blonk, 2001). This is closely linked to both increased extraction of resources and increased water use. Research based on measurements of the loss of forest area, freshwater and marine species, indicates that the 'health' of the world's ecosystems has declined by 30% in the past 25 years (WWF, 1998).

USABLE AND LESS USABLE RESOURCES

It is also common to classify resources into 'usable' and 'less usable'.The earth's crust contains an inf initeamountof ore.The problem of extracting it is a question of economy, available technology, effects on the landscape and environment and energy consumption. At the beginning of 1900 it was estimated that, for a source of copper to be exploitable there should beat least 3% copper in the ore; by 1970, the level had fallen to 0.6%. Resources that have been uneconomical to extract in the past can become a viable proposition; this is both due to rising value and better extraction technologies. For example, a more efficient technology for stone extraction would give this material afresh start for use in construction.Thesum of usableand less usable resources is also called the 'reserve base', whilst the usable resources are called 'reserves'.

There are also cases where economic conditions and developing technology have a negative impact onthe extraction of rawmaterials;forexample, technical mechanization in the timber industry has made hilly forests inaccessible. Only by using a horse or other small-scale equipment should timber be retrieved from such a forest, but this is rarely the way of the modern timber industry, despite the fact that it causes the least damage to the forest. In the same way, modern technology cannot cope with small deposits of metallic ores - modern mining needs large amounts of ore to make it economical.

Political situations can also affect the availability of raw materials. The civil war in Zaire increased the price of cobalt by 700%, as Zaire has the world's largest deposits of cobalt. Similarly, the situation in the Persian Gulf has affected the price of oil for many years. The United States Department of Domestic Affairs has made a list of 'critical minerals'. In addition to cobalt it includes bauxite for aluminium production, copper, nickel, lead, zinc, manganeseandiron;inotherwords,quiteafewofthe most important metals (USCongress,1983).

USED AND UNUSED RESOURCES

Resources can also be categorized as 'used'or 'unused'.The total number of different plant species for all of Scandinavia is about 1500. Of these only two to three are widely used for building,10 are used occasionally, whilst some 60 further species have potential for use.

A further example is flint, which was once amongst the most Important resources available, but is virtually left unused now. Similarly, it can be said that in 1840 oil was an almost totally unexploited 'non-resource'.

In 1933 the geographer Zimmermann stated: 'Resources are not anything static, but something as dynamic as civilization itself'. However, this statement does not offer us much ground for optimism. With accelerating rates of exploitation, we are on the verge of bankruptcy in many important raw materials (Weiszacker, 1998; Rodenburg, 2000). Those at a real risk of exhaustion are mineral ores and fossil oils; but for several renewables, prospects are not good either. Problems related to tropical timber are well known, and discussions centre around the effect of different forms of management, tax rates, replanting, etc. Conditions for the renewability or failure of important biological resources are very likely to change quickly as a result of increased climate change, in particular alterations in temperatures and precipitation.

It is quite absurd that our planet's stocks of raw materials should be stripped and disappear in just a fraction of the time-span of human existence - whether by that we mean two, ten or fifty generations. Even a traditional 'anthropocentric' morality with a limited time perspective requires that use of such raw materials be allowed only in special circumstances, and that recycling should be mandatory.

A differentiation is also made between material resources - the actual constituents of a resource and energy resources - the type and amount of energy needed to produce the material.

Was this article helpful?

0 0

Post a comment