Resources could be considered as Natural Capital. This is capital which cannot be restored. That is, what is labeled by economists as ordinary capital can be restored from depreciation and maintenance funds by spending money. The natural resources of the earth cannot.

Oil is made in the earth at a very slow rate. If we used it at the rate it is made our skies would be clear and the air would be breathable, even in cities (which might be small).

Sheikh Zaki Yamani the former oil minister of Saudi Arabia predicted that there would be an oil crisis in the mid 1990s as several large sources of non-Arab oil become exhausted. (But perhaps he was wrong, as oil prices in 1994 are lower than in 1972). However, by 2005 they have risen considerably. Have we reached the time of Peak Oil?

But every other source of minerals which are taken into industry, turned into consumer goods and then dumped is finite. It would be wise not to remain dependent on these.

There will always be doubt as to the exact amount of resources available. There can be no doubt that they are finite.

One measure of the impact of the world population is the quantity of resources per person. At present it is said that 2% of the world's population - in the United States - uses 25% of the world's oil production. The least that can be said about this is that this is an unstable situation. Many of those not using the resources will tend to see it as unfair. Modern electronic communications make it likely that they will become aware of it. What they will do about it, if anything, remains to be seen. The Iraq-Kuwait war may be the first act of a struggle among increasing numbers of people for decreasing quantities of resources. The aftermath showed that Iraq was actively developing nuclear weapons and already possessed the "poor man's nuclear weapon" : poison gas. If the poor countries decide to force the west to pay attention to their needs they may develop means to do so. Already gas has been used by terrorists several times in Japan.

Does the market system automatically respond to signals of future scarcity? Probably not.

Some traditional societies believe that the land does not belong to us but to the ancestors and the descendants and that it is our duty to hand it on in as good condition as we received it. One formulation is that "It is only borrowed from our children" .

The most successful and long lasting human cultures are those which have lived on income from solar energy rather than capital.

Modern economies are dependent on oil and minerals which cannot be renewed. Our grandchildren won't need to argue about oil pollution. How many will there be of them?

If renewables are not in use to replace oil, coal and minerals when they run out, our civilization will go the way of Tyre and Nineveh, Greece and Rome - and the Mayas. The future ought to belong to wind, solar, tidal, wave energy and such materials as wood, plastic from starch and so on. If these are developed now they can take over. If not, the picture we should have of the future is not pleasant.

Some writers (for example in "The Limits to Growth" 1972) have suggested that a culture of the arts, ritual and philosophy rather than production and consumption is the only long term solution to both resource depletion and pollution. Perhaps the Amish of Pennsylvania may be a model. The same writers indicate that a cessation of population increase is also necessary. Later reports of the Club of Rome are less pessimistic and support "sustainable growth" .

However, there is a school of economists - The Cornucopians - who argue that there can never be a shortage of raw materials as human ingenuity can always devise substitutes. They cite the development of iron when tin became unavailable in the first millennium BC and the use of aluminum to replace copper when copper prices rose in the 1960s. Their view is that the planet can support any number of people. Is this more than the fantasy of a child in a rich household who believes there is no end to things?

It would be rather important to know which of these views is right. Are there for example certain key resources which cannot be substituted for? Water for agriculture might be one of these. Some ecologists believe the buffering capacity of the earth's natural biological systems to absorb pollutants (non-biogenic substances) may be another. Already, the Ozone layer cannot absorb any more CFCs.

A compromise between these views might be that the earth can support more people with ingenuity but that the speed of growth at present is too high to allow new ideas and techniques to become effective quickly enough to affect the number of people we have already. Thus the people of areas such as Mexico where the population is growing fast cannot adopt new techniques because the costs of education of all the increased numbers of people is too high. Even areas of stable population size do not spend enough on education to spread knowledge of new techniques. The transition from bronze to iron took several centuries.

Recent low prices of oil may have provoked a feeling of false optimism, replaced by the sudden rise of oil prices in 2004-7 and the spike in 2008.

A low price of oil is likely to inhibit solar research and other developments which would reduce the effects of the fundamental problem. Hopefully, higher prices will stimulate research and investment in solar derivatives.